Anatomy-Based Filler Injection: Treatment Techniques for Supraorbital Hollowness and Charming Roll

Abstract

Supraorbital hollowness and pretarsal fullness, commonly known as the sunken eyelid and charming roll, respectively, are significant anatomical features that impact the aesthetic appearance of the periorbital region. Supraorbital hollowness is characterized by a recessed appearance of the upper eyelid, often attributed to genetic factors, aging, or surgical alterations, such as excessive fat removal during blepharoplasty. This condition is particularly prevalent among East Asians due to anatomical differences, such as weaker levator muscles and unique fat distribution patterns. Pretarsal fullness, also known as aegyo-sal, enhances the youthful and expressive appearance of the lower eyelid, forming a roll above the lash line that is considered aesthetically desirable in East Asian culture. Anatomical-based filler injection techniques are critical for correcting these features, involving precise placement within the correct tissue planes to avoid complications and achieve natural-looking results. This approach not only improves the aesthetic appeal of the eyelid but also enhances the overall facial harmony, emphasizing the importance of tailored procedures based on individual anatomy and cultural preferences.

Full text

Academic Editor: Arianna Di Stadio
Received: 30 September 2024
Revised: 6 February 2025
Accepted: 12 February 2025
Published: 15 February 2025
Citation: Hong, G.-W.; Choi, W.; Wan,
J.; Yoon, S.E.; Bautzer, C.; Basmage, L.;
Leite, P.; Yi, K.-H. Anatomy-Based
Filler Injection: Treatment Techniques
for Supraorbital Hollowness and
Charming Roll. Life 2025,15, 304.
https://doi.org/10.3390/life
15020304
Copyright: © 2025 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license
(https://creativecommons.org/
licenses/by/4.0/).
Review
Anatomy-Based Filler Injection: Treatment Techniques for
Supraorbital Hollowness and Charming Roll
Gi-Woong Hong 1, Wonseok Choi 2, Jovian Wan 3, Song Eun Yoon 4, Carlos Bautzer 5, Lucas Basmage 6,
Patricia Leite 7and Kyu-Ho Yi 8,9 ,*
1Samskin Plastic Surgery Clinic, Seoul 06577, Republic of Korea
2V Plastic Surgery, Daegu, Republic of Korea
3Medical Research Inc., Seoul, Republic of Korea
4Brandnew Aesthetic Surgery Clinic, Seoul, Republic of Korea
5Lifestyle Clinic, Sao Paulo, Brazil
6Synergie Clinic, Campo Grande, Brazil
7Patricia Leite Clinic, Belo Horizonte, Brazil
8Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification
Research Institute, BK21 FOUR Project, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu,
Seoul 03722, Republic of Korea
9You & I Clinic (Mokdong), Seoul 06001, Republic of Korea
*Correspondence: kyuho90@daum.net
Abstract: Supraorbital hollowness and pretarsal fullness, commonly known as the sunken
eyelid and charming roll, respectively, are significant anatomical features that impact the
aesthetic appearance of the periorbital region. Supraorbital hollowness is characterized
by a recessed appearance of the upper eyelid, often attributed to genetic factors, aging, or
surgical alterations, such as excessive fat removal during blepharoplasty. This condition is
particularly prevalent among East Asians due to anatomical differences, such as weaker
levator muscles and unique fat distribution patterns. Pretarsal fullness, also known as
aegyo-sal, enhances the youthful and expressive appearance of the lower eyelid, forming
a roll above the lash line that is considered aesthetically desirable in East Asian culture.
Anatomical-based filler injection techniques are critical for correcting these features, in-
volving precise placement within the correct tissue planes to avoid complications and
achieve natural-looking results. This approach not only improves the aesthetic appeal of
the eyelid but also enhances the overall facial harmony, emphasizing the importance of
tailored procedures based on individual anatomy and cultural preferences.
Keywords: supraorbital hollowness; hyaluronic acid fillers; periorbital rejuvenation; eyebrow
anatomy; pretarsal fullness
1. Introduction
Supraorbital hollowness, commonly referred to as sunken eyelid, is a condition char-
acterized by a recessed appearance of the upper eyelid that imparts a fatigued, aged, or
sleepy look. This appearance can result from congenital factors, natural aging processes, or
procedures such as blepharoplasty that involve the excessive removal of orbital fat [
1
–
7
].
Individuals, particularly those of East Asian descent, are more prone to this condition
due to anatomical differences, including a generally weaker levator palpebrae superioris
muscle that often lacks attachment to the dermal tissue. As a result, the eyelid does not
fully retract when the eyes are open, contributing to the appearance of thickened skin and
a lack of double eyelid formation [
8
]. Age-related changes further exacerbate the condition
Life 2025,15, 304 https://doi.org/10.3390/life15020304

Life 2025,15, 304 2 of 18
as fat beneath the orbital septum diminishes, leading to a more pronounced hollow look
and sagging skin [
9
]. This effect, combined with the structural characteristics of the upper
eyelid and surrounding areas, results in the distinctive sunken appearance associated with
supraorbital hollowness.
Flat eyebrows, often seen in conjunction with supraorbital hollowness, can significantly
impact the overall facial aesthetic. The position, shape, and volume of the eyebrows play
a crucial role in defining facial expressions and impressions. In many cases, East Asians
experience a greater accumulation of subcutaneous fat in the upper eyelid and brow region,
contributing to a swollen appearance that becomes more pronounced with age. As the
eyebrows lose volume and descend over time, they can further accentuate the hollow look
of the supraorbital area. Proper pre-treatment considerations, including the evaluation of
the patient’s facial structure, anatomy, and aesthetic goals, are essential to developing an
effective treatment plan. By addressing these factors, enhancing the hollow areas along the
orbital rim and adjusting the eyebrow shape, a more youthful and alert appearance can be
achieved, ultimately improving the overall aesthetic harmony of the eyes and face.
The popularity of pretarsal roll or charming roll fillers, especially among Koreans,
stems from cultural preferences for a youthful, expressive eye appearance. Known as
“aegyo-sal”, the enhanced lower eyelid roll is seen as adding charm and a fresh, lively look,
which aligns with East Asian beauty ideals that favor youthful, natural features. In this
context, pretarsal roll fillers play a central role in achieving this aesthetic, with many opting
for subtle filler techniques that emphasize this feature without compromising the natural
eyelid contour.
The primary objective of this study is to provide an anatomy-based approach to filler
injection techniques in the periorbital region, focusing on the treatment of supraorbital
hollowness and enhancement of pretarsal fullness, or “aegyo-sal”. This review aims to
address the unique anatomical considerations required for achieving natural and balanced
aesthetic outcomes, particularly in East Asian populations, who may present with specific
anatomical characteristics such as distinct fat distribution patterns and muscle attachments.
The hypothesis driving this review is that precision-based filler injections, tailored to
anatomical planes within the periorbital area, can enhance aesthetic outcomes by providing
effective, natural-looking volume restoration while minimizing risks of complications such
as vascular occlusion, bruising, and filler migration. Through a structured review of existing
literature and anatomical analysis, this study seeks to provide clinicians with practical,
evidence-based recommendations to guide safe and effective periorbital filler procedures.
2. Materials and Methods
Keywords including “Supraorbital Hollowness”, “Sunken Eyelid”, “Pretarsal Full-
ness”, “Charming Roll”, “Hyaluronic Acid Fillers”, “Eyebrow Rejuvenation”, and “Peri-
orbital Rejuvenation” were searched in the MEDLINE, PubMed, and Ovid databases for
relevant studies published on anatomical insights, clinical approaches, and treatment tech-
niques specific to the periorbital region. This search yielded a total of 182 studies. Studies
were further reviewed based on criteria such as detailed descriptions of injection techniques,
anatomical dissections, and specific outcomes in periorbital rejuvenation, especially among
East Asian populations. After applying these criteria, 150 studies were excluded due to
lack of detailed methodology, limited sample size, or the absence of objective outcome
measurements, resulting in a final selection of 32 studies. All studies were then classified
according to the Oxford Centre for Evidence-Based Medicine evidence hierarchy.

Life 2025,15, 304 3 of 18
3. Supraorbital Hollowness (Sunken Eyelid) and Flat Eyebrow
3.1. Pre-Treatment Considerations
Supraorbital hollowness, often termed sunken eyelid, is characterized by a recessed
appearance of the upper eyelid, either due to congenital factors or the natural aging
process [
10
]. This condition imparts a fatigued, sleepy, or aged look [
11
]. Contributing
factors include genetic predisposition, age-related loss of eyelid fat, or the excessive removal
of orbital fat during blepharoplasty [
12
–
14
]. In particular, East Asians may experience this
condition more prominently due to anatomical differences [
15
]. The levator palpebrae
superioris muscle, which elevates the upper eyelid by attaching to the tarsal plate, is
generally weaker in this population and frequently lacks attachment to the dermal tissue.
Consequently, the upper eyelid does not retract fully when the eyes are open, preventing
the formation of a double eyelid and resulting in the appearance of sagging and thickened
skin [16,17].
East Asians commonly exhibit a greater accumulation of subcutaneous fat in the
upper eyelid and the surrounding eyebrow region. As this fat descends, it contributes to
a swollen and puffy appearance of the upper eyelid [
18
]. With advancing age, the outer
portion of the eyelid, particularly outside the tarsal plate, may experience sagging and
become more pronounced, while the area around the orbital margin may appear hollow
due to the reduction in fat beneath the orbital septum. This progressive weakening of the
eyelid muscles with age results in senile ptosis and increased skin sagging, leading to a
characteristic sunken appearance of the eyelid, which can look hollow and fatigued [17].
A sunken eyelid often conveys a tired and sleepy appearance, with the eyes lacking
sharpness, resembling ptosis [
11
]. This condition typically results in the development of a
prominent supratarsal lid crease, which appears along the orbital margin and is situated
significantly higher than the upper margin of the tarsal plate, where the typical double
eyelid crease forms. When such a pronounced orbital lid crease develops, the skin tends to
fold inward at this elevated crease rather than at the double eyelid line below, causing the
lower crease to become less defined and blurred. In these instances, enhancing the hollow
areas along the orbital rim can improve the tired and sleepy appearance. This procedure
also helps to soften the pronounced orbital lid crease, thereby making the lower double
eyelid crease more defined and prominent. As a result, the overall appearance of the eyes
becomes sharper and more alert (Figure 1) [19].
Life 2025, 15, x FOR PEER REVIEW 3 of 19
3. Supraorbital Hollowness (Sunken Eyelid) and Flat Eyebrow
3.1. Pre-Treatment Considerations
Supraorbital hollowness, often termed sunken eyelid, is characterized by a recessed
appearance of the upper eyelid, either due to congenital factors or the natural aging pro-
cess [10]. This condition imparts a fatigued, sleepy, or aged look [11]. Contributing factors
include genetic predisposition, age-related loss of eyelid fat, or the excessive removal of
orbital fat during blepharoplasty [12–14]. In particular, East Asians may experience this
condition more prominently due to anatomical differences [15]. The levator palpebrae su-
perioris muscle, which elevates the upper eyelid by aaching to the tarsal plate, is gener-
ally weaker in this population and frequently lacks aachment to the dermal tissue. Con-
sequently, the upper eyelid does not retract fully when the eyes are open, preventing the
formation of a double eyelid and resulting in the appearance of sagging and thickened
skin [16,17].
East Asians commonly exhibit a greater accumulation of subcutaneous fat in the up-
per eyelid and the surrounding eyebrow region. As this fat descends, it contributes to a
swollen and puffy appearance of the upper eyelid [18]. With advancing age, the outer
portion of the eyelid, particularly outside the tarsal plate, may experience sagging and
become more pronounced, while the area around the orbital margin may appear hollow
due to the reduction in fat beneath the orbital septum. This progressive weakening of the
eyelid muscles with age results in senile ptosis and increased skin sagging, leading to a
characteristic sunken appearance of the eyelid, which can look hollow and fatigued [17].
A sunken eyelid often conveys a tired and sleepy appearance, with the eyes lacking
sharpness, resembling ptosis [11]. This condition typically results in the development of a
prominent supratarsal lid crease, which appears along the orbital margin and is situated
significantly higher than the upper margin of the tarsal plate, where the typical double
eyelid crease forms. When such a pronounced orbital lid crease develops, the skin tends
to fold inward at this elevated crease rather than at the double eyelid line below, causing
the lower crease to become less defined and blurred. In these instances, enhancing the
hollow areas along the orbital rim can improve the tired and sleepy appearance. This pro-
cedure also helps to soften the pronounced orbital lid crease, thereby making the lower
double eyelid crease more defined and prominent. As a result, the overall appearance of
the eyes becomes sharper and more alert (Figure 1) [19].
Figure 1. Before (A) and after (B) treatment of supraorbital hollowness.
3.2. Procedure for Treating Supraorbital Hollowness
When addressing supraorbital hollowness, it is essential to perform the procedure
with the patient in an upright position and their eyes open. The technique should involve
retrograde linear threading and tiny, slow injections using a small-particle, soft-con-
sistency hyaluronic acid (HA) filler, which allows for effective molding. Achieving
Figure 1. Before (A) and after (B) treatment of supraorbital hollowness.
3.2. Procedure for Treating Supraorbital Hollowness
When addressing supraorbital hollowness, it is essential to perform the procedure
with the patient in an upright position and their eyes open. The technique should involve
retrograde linear threading and tiny, slow injections using a small-particle, soft-consistency
hyaluronic acid (HA) filler, which allows for effective molding. Achieving optimal results
and minimizing risks depends critically on selecting the appropriate injection plane [1].

Life 2025,15, 304 4 of 18
Injecting within the orbicularis oculi muscle is generally discouraged due to the
muscle’s thinness, which complicates precise injections and increases the risk of hemorrhage
owing to the muscle’s rich vascular supply [
20
]. Additionally, although the loss of fat within
the orbital septum may lead practitioners to consider injecting directly into the orbital
fat, this approach is not recommended. Managing hemostasis in this region is difficult if
bleeding occurs, and the formation of a hematoma within the septum could damage the
septum itself, potentially compromising its role as a lubricant during eyelid movement.
The preferred injection plane for treating supraorbital hollowness is the deep fat layer
located beneath the orbicularis oculi muscle, following the margin of the orbital rim. This
layer is continuous with the retro-orbicularis oculi fat (ROOF) pad in the eyebrow region.
However, in cases of sunken eyelids, the deep fat layer within the eyelid is often minimal
or absent. Consequently, the filler should be injected into the preseptal space, which lies
beneath the orbicularis oculi muscle but outside the orbital septum (Figure 2) [21].
Life 2025, 15, x FOR PEER REVIEW 4 of 19
optimal results and minimizing risks depends critically on selecting the appropriate injec-
tion plane [1].
Injecting within the orbicularis oculi muscle is generally discouraged due to the mus-
cle’s thinness, which complicates precise injections and increases the risk of hemorrhage
owing to the muscle’s rich vascular supply [20]. Additionally, although the loss of fat within
the orbital septum may lead practitioners to consider injecting directly into the orbital fat,
this approach is not recommended. Managing hemostasis in this region is difficult if bleed-
ing occurs, and the formation of a hematoma within the septum could damage the septum
itself, potentially compromising its role as a lubricant during eyelid movement.
The preferred injection plane for treating supraorbital hollowness is the deep fat layer
located beneath the orbicularis oculi muscle, following the margin of the orbital rim. This
layer is continuous with the retro-orbicularis oculi fat (ROOF) pad in the eyebrow region.
However, in cases of sunken eyelids, the deep fat layer within the eyelid is often minimal or
absent. Consequently, the filler should be injected into the preseptal space, which lies be-
neath the orbicularis oculi muscle but outside the orbital septum (Figure 2) [21].
Figure 2. Anatomical layers of the supraorbital region.
The medial portion of the orbital rim contains critical vascular structures, including
the supratrochlear and supraorbital arteries, both branches of the ophthalmic artery sup-
plying the forehead and glabella regions. These vessels connect to the central retinal artery
within the orbit, necessitating extreme caution during procedures in this area. To mini-
mize the risk of complications such as intra-arterial injection and other forms of vascular
compromise, it is recommended to use a cannula instead of a needle (Figure 3).
Figure 2. Anatomical layers of the supraorbital region.
The medial portion of the orbital rim contains critical vascular structures, including the
supratrochlear and supraorbital arteries, both branches of the ophthalmic artery supplying
the forehead and glabella regions. These vessels connect to the central retinal artery within
the orbit, necessitating extreme caution during procedures in this area. To minimize the risk
of complications such as intra-arterial injection and other forms of vascular compromise, it
is recommended to use a cannula instead of a needle (Figure 3).
The puncture point for cannula insertion may vary slightly depending on the extent
of the hollow area, but it is generally located where a vertical line drawn from the lateral
canthus intersects with the orbital rim. To ensure accurate placement, the entry point
should be on the skin overlying the firm orbital rim, rather than on the looser skin below
the rim. After insertion, the cannula should pass through the fibrous tissue of the orbicularis
retaining ligament, part of the muscle layer. Once through this tissue, a slightly looser
space beneath it can be felt. For further confirmation, the cannula should be advanced until
it touches the bone of the orbital rim, then withdrawn slightly to position it correctly in the
space just beneath the orbicularis oculi muscle (Figure 4).

Life 2025,15, 304 5 of 18
Life 2025, 15, x FOR PEER REVIEW 5 of 19
Figure 3. Vascular structures of the orbital region.
The puncture point for cannula insertion may vary slightly depending on the extent
of the hollow area, but it is generally located where a vertical line drawn from the lateral
canthus intersects with the orbital rim. To ensure accurate placement, the entry point
should be on the skin overlying the firm orbital rim, rather than on the looser skin below
the rim. After insertion, the cannula should pass through the fibrous tissue of the orbicu-
laris retaining ligament, part of the muscle layer. Once through this tissue, a slightly looser
space beneath it can be felt. For further confirmation, the cannula should be advanced
until it touches the bone of the orbital rim, then withdrawn slightly to position it correctly
in the space just beneath the orbicularis oculi muscle (Figure 4).
Figure 4. Injection entry point and technique for the cannula. Injection entry point: Vertical line
drawn above or outside the lateral canthus, around the lower margin of the superior orbital rim.
Focus on the medial and middle parts of the periorbital rim, under the brow, to avoid the supraor-
bital and supratrochlear main arteries. Above the supratarsal lid crease and below the orbicularis
retaining ligament. Injection technique: Patient in vertical siing position with voluntarily opened
eyes. Retrograde linear tiny injection technique with very slow release.
Figure 3. Vascular structures of the orbital region.
Life 2025, 15, x FOR PEER REVIEW 5 of 19
Figure 3. Vascular structures of the orbital region.
The puncture point for cannula insertion may vary slightly depending on the extent
of the hollow area, but it is generally located where a vertical line drawn from the lateral
canthus intersects with the orbital rim. To ensure accurate placement, the entry point
should be on the skin overlying the firm orbital rim, rather than on the looser skin below
the rim. After insertion, the cannula should pass through the fibrous tissue of the orbicu-
laris retaining ligament, part of the muscle layer. Once through this tissue, a slightly looser
space beneath it can be felt. For further confirmation, the cannula should be advanced
until it touches the bone of the orbital rim, then withdrawn slightly to position it correctly
in the space just beneath the orbicularis oculi muscle (Figure 4).
Figure 4. Injection entry point and technique for the cannula. Injection entry point: Vertical line
drawn above or outside the lateral canthus, around the lower margin of the superior orbital rim.
Focus on the medial and middle parts of the periorbital rim, under the brow, to avoid the supraor-
bital and supratrochlear main arteries. Above the supratarsal lid crease and below the orbicularis
retaining ligament. Injection technique: Patient in vertical siing position with voluntarily opened
eyes. Retrograde linear tiny injection technique with very slow release.
Figure 4. Injection entry point and technique for the cannula. Injection entry point: Vertical line
drawn above or outside the lateral canthus, around the lower margin of the superior orbital rim.
Focus on the medial and middle parts of the periorbital rim, under the brow, to avoid the supraorbital
and supratrochlear main arteries. Above the supratarsal lid crease and below the orbicularis retaining
ligament. Injection technique: Patient in vertical sitting position with voluntarily opened eyes.
Retrograde linear tiny injection technique with very slow release.
Next, the cannula should be advanced along the hollow groove of the orbital rim,
maintaining a consistent depth throughout the procedure. It is critical to ensure that the
cannula tip reaches the desired location while preserving the initial depth. If fibrous tissue
is encountered, gently moving the cannula back and forth can create space and facilitate
smooth advancement. Once the target position is reached, the cannula should be slowly
withdrawn while carefully injecting small amounts of HA filler. This method minimizes
the risk of creating an uneven surface. As previously mentioned, since there is little to no
fat layer beneath the orbicularis oculi muscle, the cannula should remain in the preseptal
space, outside the orbital septum (Figure 5).

Life 2025,15, 304 6 of 18
Life 2025, 15, x FOR PEER REVIEW 6 of 19
Next, the cannula should be advanced along the hollow groove of the orbital rim,
maintaining a consistent depth throughout the procedure. It is critical to ensure that the
cannula tip reaches the desired location while preserving the initial depth. If fibrous tissue
is encountered, gently moving the cannula back and forth can create space and facilitate
smooth advancement. Once the target position is reached, the cannula should be slowly
withdrawn while carefully injecting small amounts of HA filler. This method minimizes
the risk of creating an uneven surface. As previously mentioned, since there is lile to no
fat layer beneath the orbicularis oculi muscle, the cannula should remain in the preseptal
space, outside the orbital septum (Figure 5).
Figure 5. Anatomy of the preseptal space.
During the procedure, it is crucial to continuously monitor the depth and volume of
the filler to avoid injecting too superficially or excessively, as this can result in noticeable
lumpiness or bulging when the patient closes their eyes. Overcorrection can cause the eyes
to appear swollen or lead to filler migration to the lower eyelid. Therefore, it is safer to
perform a moderate correction and evaluate the results before making further adjust-
ments.
After achieving the desired correction, if areas appear underfilled or if the contours
are not smooth, a small amount of very soft HA filler can be injected into the subdermal
layer to refine the surface. Given the thinness of the eyelid skin, care must be taken to
prevent the formation of beads or nodules during this final step (Figure 6).
Figure 5. Anatomy of the preseptal space.
During the procedure, it is crucial to continuously monitor the depth and volume of
the filler to avoid injecting too superficially or excessively, as this can result in noticeable
lumpiness or bulging when the patient closes their eyes. Overcorrection can cause the eyes
to appear swollen or lead to filler migration to the lower eyelid. Therefore, it is safer to
perform a moderate correction and evaluate the results before making further adjustments.
After achieving the desired correction, if areas appear underfilled or if the contours are
not smooth, a small amount of very soft HA filler can be injected into the subdermal layer
to refine the surface. Given the thinness of the eyelid skin, care must be taken to prevent
the formation of beads or nodules during this final step (Figure 6).
Life 2025, 15, x FOR PEER REVIEW 7 of 19
Figure 6. Injection planes: Supraperiosteal and submuscular injections around the orbital rim over
the orbital septum to fill the hollowness. Subdermal injection of very soft HA filler to smooth the
surface and remove unnecessary multiple eyelid lines.
Patients with severe ptosis or significant ocular protrusion may not achieve favorable
outcomes from this procedure, and their symptoms could worsen, making treatment in-
advisable in such cases. Additionally, the presence of scar tissue from previous surgeries
or trauma may complicate even filler distribution, and this should be carefully considered
during treatment planning.
3.3. Procedure for Treating Flat Eyebrows
The position, shape, and volume of the eyebrows, situated just below the forehead,
play a critical role in shaping a person’s overall facial impression. As individuals age, the
volume in the eyebrow region diminishes, leading to a downward shift in the eyebrows
[5,22]. This phenomenon is more prominent in Western populations compared to East Asian
populations, a difference attributable to variations in bone structure and skin thickness [23].
Eyebrows, traditionally understood as the arch-shaped hair along the raised area of
the supraorbital ridge—the bony prominence above the eye socket—typically measure
between 7 to 11 mm in width and approximately 5 to 6 cm in length [24]. The growth
paern and shape of the eyebrows are influenced by factors such as race, gender, and age
[25]. Unlike scalp hair, eyebrow hair has a shorter growth phase, which results in its rela-
tively shorter length [26].
The skin in the eyebrow area is governed by several facial muscles, including the
frontalis muscle, orbicularis oculi muscle, corrugator supercilii muscle, and procerus mus-
cle. These muscles facilitate eyebrow movement during facial expressions, thereby en-
hancing facial expressiveness and enabling effective communication [27].
The primary functional role of eyebrows is ocular protection. They prevent rain,
snow, and sweat from directly entering the eyes. Additionally, the raised orbital bone be-
neath the eyebrows acts as a barrier against dust and small particles, while also providing
shade to protect the eyes from sunlight and bright light [28]. Beyond their protective func-
tion, the movement of the eyebrows during facial expressions significantly influences a
person’s overall facial expression, conveying emotions such as surprise or anger. The
shape of the eyebrows is a key determinant of a person’s appearance. In East Asian phys-
iognomy, the shape of the eyebrows is believed to reflect an individual’s personality,
Figure 6. Injection planes: Supraperiosteal and submuscular injections around the orbital rim over
the orbital septum to fill the hollowness. Subdermal injection of very soft HA filler to smooth the
surface and remove unnecessary multiple eyelid lines.
Patients with severe ptosis or significant ocular protrusion may not achieve favorable
outcomes from this procedure, and their symptoms could worsen, making treatment
inadvisable in such cases. Additionally, the presence of scar tissue from previous surgeries
or trauma may complicate even filler distribution, and this should be carefully considered
during treatment planning.

Life 2025,15, 304 7 of 18
3.3. Procedure for Treating Flat Eyebrows
The position, shape, and volume of the eyebrows, situated just below the forehead, play
a critical role in shaping a person’s overall facial impression. As individuals age, the volume
in the eyebrow region diminishes, leading to a downward shift in the eyebrows [
5
,
22
].
This phenomenon is more prominent in Western populations compared to East Asian
populations, a difference attributable to variations in bone structure and skin thickness [
23
].
Eyebrows, traditionally understood as the arch-shaped hair along the raised area of
the supraorbital ridge—the bony prominence above the eye socket—typically measure
between 7 to 11 mm in width and approximately 5 to 6 cm in length [
24
]. The growth
pattern and shape of the eyebrows are influenced by factors such as race, gender, and
age [
25
]. Unlike scalp hair, eyebrow hair has a shorter growth phase, which results in its
relatively shorter length [26].
The skin in the eyebrow area is governed by several facial muscles, including the
frontalis muscle, orbicularis oculi muscle, corrugator supercilii muscle, and procerus muscle.
These muscles facilitate eyebrow movement during facial expressions, thereby enhancing
facial expressiveness and enabling effective communication [27].
The primary functional role of eyebrows is ocular protection. They prevent rain, snow,
and sweat from directly entering the eyes. Additionally, the raised orbital bone beneath the
eyebrows acts as a barrier against dust and small particles, while also providing shade to
protect the eyes from sunlight and bright light [
28
]. Beyond their protective function, the
movement of the eyebrows during facial expressions significantly influences a person’s
overall facial expression, conveying emotions such as surprise or anger. The shape of
the eyebrows is a key determinant of a person’s appearance. In East Asian physiognomy,
the shape of the eyebrows is believed to reflect an individual’s personality, image, and
even fortune, leading to an increasing interest among men in eyebrow grooming and
shaping [29–31].
Although the loss of volume and subsequent drooping of the eyebrows due to aging is
generally less pronounced in East Asians, Western individuals often place greater emphasis
on the position and volume of the eyebrows, considering them crucial to achieving a softer
facial expression [32].
3.4. Optimal Eyebrow Position and Shape
The ideal position and shape of the eyebrows are typically determined by specific
facial landmarks. The inner end of the eyebrow should align vertically with the lateral
margin of the nasal alae, while the outer end should align with a line drawn from the
lateral margin of the nasal alae through the lateral canthus of the eye. The highest point of
the eyebrow, usually located at the lateral third, should be positioned along a vertical line
drawn from the lateral limbus of the eye (Figure 7) [24,33,34].
Considering the proportional relationship between the eyes and eyebrows, when
the width of the eye (L) is set as 1 unit, the straight length of the eyebrow (W) should
ideally measure approximately 1.63 units. The distance from the medial canthus of the
eye to the inner end of the eyebrow (MH) should be around 0.53 units, while the distance
from the lateral canthus to the outer end of the eyebrow (LH) should be about 0.60 units.
The distance from the center of the pupil to the eyebrow (PH) should be approximately
0.36 units (Figure 8) [35].
However, it is important to recognize that eyebrow shapes vary according to ethnicity,
culture, and fashion trends. In Korea, for instance, eyebrow tattooing has become highly
popular, with reports suggesting that nearly all older women engage in this practice,
typically favoring straight eyebrows. Despite such trends, it is crucial to acknowledge

Life 2025,15, 304 8 of 18
that the most suitable eyebrow shape may vary depending on the individual’s facial
structure [36].
Life 2025, 15, x FOR PEER REVIEW 8 of 19
image, and even fortune, leading to an increasing interest among men in eyebrow groom-
ing and shaping [29–31].
Although the loss of volume and subsequent drooping of the eyebrows due to aging
is generally less pronounced in East Asians, Western individuals often place greater em-
phasis on the position and volume of the eyebrows, considering them crucial to achieving
a softer facial expression [32].
3.4. Optimal Eyebrow Position and Shape
The ideal position and shape of the eyebrows are typically determined by specific
facial landmarks. The inner end of the eyebrow should align vertically with the lateral
margin of the nasal alae, while the outer end should align with a line drawn from the
lateral margin of the nasal alae through the lateral canthus of the eye. The highest point
of the eyebrow, usually located at the lateral third, should be positioned along a vertical
line drawn from the lateral limbus of the eye (Figure 7) [24,33,34].
Figure 7. Ideal position and shape of the eyebrow.
Considering the proportional relationship between the eyes and eyebrows, when the
width of the eye (L) is set as 1 unit, the straight length of the eyebrow (W) should ideally
measure approximately 1.63 units. The distance from the medial canthus of the eye to the inner
end of the eyebrow (MH) should be around 0.53 units, while the distance from the lateral
canthus to the outer end of the eyebrow (LH) should be about 0.60 units. The distance from
the center of the pupil to the eyebrow (PH) should be approximately 0.36 units (Figure 8) [35].
Figure 7. Ideal position and shape of the eyebrow.
Life 2025, 15, x FOR PEER REVIEW 9 of 19
Figure 8. Ratio difference between the size of the eye and eyebrow.
However, it is important to recognize that eyebrow shapes vary according to ethnicity,
culture, and fashion trends. In Korea, for instance, eyebrow tattooing has become highly
popular, with reports suggesting that nearly all older women engage in this practice, typi-
cally favoring straight eyebrows. Despite such trends, it is crucial to acknowledge that the
most suitable eyebrow shape may vary depending on the individual’s facial structure [36].
Globally, eyebrow shapes can be broadly categorized into four common types:
arched, head-up, tail-up, and horizontal (Figure 9).[37]. While straight eyebrows have be-
come a popular trend in Korea, with many considering this to be the preferred shape
among Koreans, surveys indicate that over half of Koreans favor a naturally arched eye-
brow shape [38]. A notable difference in preference between Eastern and Western cultures
is that while East Asians often perceive the tail-up eyebrow shape as overly harsh and
therefore less desirable, many Westerners favor this shape as much as they do the arched
style. This difference in preference is likely influenced by the fundamental differences in
facial structure between Eastern and Western populations, as well as cultural tendencies
in the West to embrace more prominent and defined features.
Figure 9. Common classification of eyebrow shapes around the world.
Regardless of personal preferences, it is advisable for individuals to select an eye-
brow shape that complements their facial features. Healthcare providers should consider
this harmony when recommending eyebrow shapes. The current trend toward straight
eyebrows, driven by the popularity of eyebrow taoos, often overlooks the fact that the
most suitable eyebrow shape varies depending on face shape. Generally, for a round face,
somewhat angular, short, and high eyebrows are more flaering; for a square face,
rounded arched eyebrows are ideal; and for longer faces, a more horizontal, straight eye-
brow shape is considered more appropriate.
Figure 8. Ratio difference between the size of the eye and eyebrow.
Globally, eyebrow shapes can be broadly categorized into four common types: arched,
head-up, tail-up, and horizontal (Figure 9) [
37
]. While straight eyebrows have become
a popular trend in Korea, with many considering this to be the preferred shape among
Koreans, surveys indicate that over half of Koreans favor a naturally arched eyebrow
shape [
38
]. A notable difference in preference between Eastern and Western cultures is that
while East Asians often perceive the tail-up eyebrow shape as overly harsh and therefore
less desirable, many Westerners favor this shape as much as they do the arched style.
This difference in preference is likely influenced by the fundamental differences in facial
structure between Eastern and Western populations, as well as cultural tendencies in the
West to embrace more prominent and defined features.

Life 2025,15, 304 9 of 18
Life 2025, 15, x FOR PEER REVIEW 9 of 19
Figure 8. Ratio difference between the size of the eye and eyebrow.
However, it is important to recognize that eyebrow shapes vary according to ethnicity,
culture, and fashion trends. In Korea, for instance, eyebrow tattooing has become highly
popular, with reports suggesting that nearly all older women engage in this practice, typi-
cally favoring straight eyebrows. Despite such trends, it is crucial to acknowledge that the
most suitable eyebrow shape may vary depending on the individual’s facial structure [36].
Globally, eyebrow shapes can be broadly categorized into four common types:
arched, head-up, tail-up, and horizontal (Figure 9).[37]. While straight eyebrows have be-
come a popular trend in Korea, with many considering this to be the preferred shape
among Koreans, surveys indicate that over half of Koreans favor a naturally arched eye-
brow shape [38]. A notable difference in preference between Eastern and Western cultures
is that while East Asians often perceive the tail-up eyebrow shape as overly harsh and
therefore less desirable, many Westerners favor this shape as much as they do the arched
style. This difference in preference is likely influenced by the fundamental differences in
facial structure between Eastern and Western populations, as well as cultural tendencies
in the West to embrace more prominent and defined features.
Figure 9. Common classification of eyebrow shapes around the world.
Regardless of personal preferences, it is advisable for individuals to select an eye-
brow shape that complements their facial features. Healthcare providers should consider
this harmony when recommending eyebrow shapes. The current trend toward straight
eyebrows, driven by the popularity of eyebrow taoos, often overlooks the fact that the
most suitable eyebrow shape varies depending on face shape. Generally, for a round face,
somewhat angular, short, and high eyebrows are more flaering; for a square face,
rounded arched eyebrows are ideal; and for longer faces, a more horizontal, straight eye-
brow shape is considered more appropriate.
Figure 9. Common classification of eyebrow shapes around the world.
Regardless of personal preferences, it is advisable for individuals to select an eye-
brow shape that complements their facial features. Healthcare providers should consider
this harmony when recommending eyebrow shapes. The current trend toward straight
eyebrows, driven by the popularity of eyebrow tattoos, often overlooks the fact that the
most suitable eyebrow shape varies depending on face shape. Generally, for a round face,
somewhat angular, short, and high eyebrows are more flattering; for a square face, rounded
arched eyebrows are ideal; and for longer faces, a more horizontal, straight eyebrow shape
is considered more appropriate.
As individuals age, the retro-orbicularis oculi fat (ROOF) layer beneath the orbicularis
oculi muscle, which provides volume to the eyebrow area, may diminish, altering the shape
of the eyebrow–lid complex and causing the eyebrows to appear droopy. Restoring volume
to the ROOF can tent and lift the eyebrows, helping to restore their original fullness and
potentially elevating the outer portion of the eyebrows as well (Figure 10) [39,40].
Life 2025, 15, x FOR PEER REVIEW 10 of 19
As individuals age, the retro-orbicularis oculi fat (ROOF) layer beneath the orbicularis
oculi muscle, which provides volume to the eyebrow area, may diminish, altering the shape
of the eyebrow–lid complex and causing the eyebrows to appear droopy. Restoring volume
to the ROOF can tent and lift the eyebrows, helping to restore their original fullness and
potentially elevating the outer portion of the eyebrows as well (Figure 10) [39,40].
Figure 10. Retro-orbicularis oculi fat (ROOF) in the eyebrow region.
Typically, the area medial to the midpupillary line is composed of firm skin tissue
that is well integrated with the underlying muscle, meaning it does not usually experience
significant sagging or volume loss. Therefore, the focus should be on restoring volume in
the area lateral to the midpupillary line. After making a needle puncture at the lateral
eyebrow end, a cannula should be inserted into the ROOF fat pad beneath the orbicularis
oculi muscle. Using a moderately viscous HA filler, volume should be appropriately en-
hanced. Subsequently, a softer filler should be injected into the dermis and subdermal
layers to ensure a smooth surface finish (Figure 11) [41].
Figure 11. Injection plane for the cannula. Submuscular injection into ROOF (retro-orbicularis oculi
fat) for eyebrow augmentation. Subdermal injection of very soft filler to even out the surface and
remove unnecessary multiple eyelid lines.
4. Pretarsal Fullness/Lower Eyelid Charming Roll
4.1. Pre-Treatment Considerations
The pretarsal margin of the lower eyelid, where the tarsal plate is located, measures
approximately 2 mm in thickness. The inner portion of the eyelid is angular, facilitating
Figure 10. Retro-orbicularis oculi fat (ROOF) in the eyebrow region.
Typically, the area medial to the midpupillary line is composed of firm skin tissue
that is well integrated with the underlying muscle, meaning it does not usually experience
significant sagging or volume loss. Therefore, the focus should be on restoring volume
in the area lateral to the midpupillary line. After making a needle puncture at the lateral
eyebrow end, a cannula should be inserted into the ROOF fat pad beneath the orbicularis
oculi muscle. Using a moderately viscous HA filler, volume should be appropriately
enhanced. Subsequently, a softer filler should be injected into the dermis and subdermal
layers to ensure a smooth surface finish (Figure 11) [41].

Life 2025,15, 304 10 of 18
Life 2025, 15, x FOR PEER REVIEW 10 of 19
As individuals age, the retro-orbicularis oculi fat (ROOF) layer beneath the orbicularis
oculi muscle, which provides volume to the eyebrow area, may diminish, altering the shape
of the eyebrow–lid complex and causing the eyebrows to appear droopy. Restoring volume
to the ROOF can tent and lift the eyebrows, helping to restore their original fullness and
potentially elevating the outer portion of the eyebrows as well (Figure 10) [39,40].
Figure 10. Retro-orbicularis oculi fat (ROOF) in the eyebrow region.
Typically, the area medial to the midpupillary line is composed of firm skin tissue
that is well integrated with the underlying muscle, meaning it does not usually experience
significant sagging or volume loss. Therefore, the focus should be on restoring volume in
the area lateral to the midpupillary line. After making a needle puncture at the lateral
eyebrow end, a cannula should be inserted into the ROOF fat pad beneath the orbicularis
oculi muscle. Using a moderately viscous HA filler, volume should be appropriately en-
hanced. Subsequently, a softer filler should be injected into the dermis and subdermal
layers to ensure a smooth surface finish (Figure 11) [41].
Figure 11. Injection plane for the cannula. Submuscular injection into ROOF (retro-orbicularis oculi
fat) for eyebrow augmentation. Subdermal injection of very soft filler to even out the surface and
remove unnecessary multiple eyelid lines.
4. Pretarsal Fullness/Lower Eyelid Charming Roll
4.1. Pre-Treatment Considerations
The pretarsal margin of the lower eyelid, where the tarsal plate is located, measures
approximately 2 mm in thickness. The inner portion of the eyelid is angular, facilitating
Figure 11. Injection plane for the cannula. Submuscular injection into ROOF (retro-orbicularis oculi
fat) for eyebrow augmentation. Subdermal injection of very soft filler to even out the surface and
remove unnecessary multiple eyelid lines.
4. Pretarsal Fullness/Lower Eyelid Charming Roll
4.1. Pre-Treatment Considerations
The pretarsal margin of the lower eyelid, where the tarsal plate is located, measures
approximately 2 mm in thickness. The inner portion of the eyelid is angular, facilitating the
close adherence of the tarsal plate to the eyeball. In contrast, the outer portion, which houses
the cilia (eyelashes), is rounder and thicker, a feature often referred to as the “charming
roll” or “aegyo-sal” (Figure 12) [42,43].
Life 2025, 15, x FOR PEER REVIEW 11 of 19
the close adherence of the tarsal plate to the eyeball. In contrast, the outer portion, which
houses the cilia (eyelashes), is rounder and thicker, a feature often referred to as the
“charming roll” or “aegyo-sal” (Figure 12) [42,43].
Figure 12. Structure of the lower eyelid roll muscle.
Pretarsal fullness, characterized by the protrusion of the orbicularis oculi muscle in
the tarsal region anterior to the tarsal plate, creates a roll-like appearance above the sub-
tarsal line, particularly evident when smiling. Notably, this area has minimal or no sub-
cutaneous fat both above and below the orbicularis oculi muscle. A prominent aegyo-sal
is associated with a youthful and charming appearance, making the eyes appear larger—
a desirable aribute in East Asian aesthetics [41]. In contrast, Western aesthetics typically
do not favor pronounced aegyo-sal, as excessive fullness can make the eyes appear
smaller; therefore, a more moderate size and shape are preferred.
For optimal aesthetic outcomes, the aegyo-sal should be symmetrical on both sides,
not droopy, and present as a continuous volume extending naturally from the inner to the
outer corner of the lower eyelid. The fullness should be positioned as close to the lash line
as possible. Typically, the aegyo-sal is not visible when the face is at rest but becomes
prominent when smiling. Ideal candidates for this procedure are those whose lower eyelid
muscles naturally form the aegyo-sal shape when the skin beneath the lower eyelid is
gently pushed upward, indicating good skin elasticity and minimal sagging.
In youth, the creation of an aegyo-sal enhances a youthful and endearing appearance
by mimicking the effect of a smiling expression. However, as one ages, the skin beneath the
eyes tends to sag, and the underlying muscles may lose tone, resulting in a reduction in the
muscle volume that supports the aegyo-sal. This leads to a flatter, more tired, and sullen
appearance. In such cases, restoring the volume of the aegyo-sal through treatment is nec-
essary to rejuvenate the area. Additionally, augmenting the aegyo-sal can also improve the
appearance of dark circles and reduce fine wrinkles due to the skin expansion effect.
When injecting fillers into the aegyo-sal area, it is recommended that the patient smile
first to identify the natural crease formed by the contraction of the lower eyelid muscle.
Care must be taken to avoid adding volume below this line. Typically, a width of 4–6 mm
from the subciliary line is appropriate. The filler can be administered to create a consistent
volume along the entire lower eyelid, resembling a roll cake, or the volume can be strate-
gically varied, with the central portion being the fullest, followed by a slightly less full
outer portion, and the least volume in the inner portion. Some patients may prefer a
slightly thicker appearance towards the lateral third of the eyelid.
Figure 12. Structure of the lower eyelid roll muscle.
Pretarsal fullness, characterized by the protrusion of the orbicularis oculi muscle in the
tarsal region anterior to the tarsal plate, creates a roll-like appearance above the subtarsal
line, particularly evident when smiling. Notably, this area has minimal or no subcutaneous
fat both above and below the orbicularis oculi muscle. A prominent aegyo-sal is associated
with a youthful and charming appearance, making the eyes appear larger—a desirable
attribute in East Asian aesthetics [
41
]. In contrast, Western aesthetics typically do not favor
pronounced aegyo-sal, as excessive fullness can make the eyes appear smaller; therefore, a
more moderate size and shape are preferred.

Life 2025,15, 304 11 of 18
For optimal aesthetic outcomes, the aegyo-sal should be symmetrical on both sides,
not droopy, and present as a continuous volume extending naturally from the inner to the
outer corner of the lower eyelid. The fullness should be positioned as close to the lash
line as possible. Typically, the aegyo-sal is not visible when the face is at rest but becomes
prominent when smiling. Ideal candidates for this procedure are those whose lower eyelid
muscles naturally form the aegyo-sal shape when the skin beneath the lower eyelid is
gently pushed upward, indicating good skin elasticity and minimal sagging.
In youth, the creation of an aegyo-sal enhances a youthful and endearing appearance
by mimicking the effect of a smiling expression. However, as one ages, the skin beneath
the eyes tends to sag, and the underlying muscles may lose tone, resulting in a reduction
in the muscle volume that supports the aegyo-sal. This leads to a flatter, more tired, and
sullen appearance. In such cases, restoring the volume of the aegyo-sal through treatment is
necessary to rejuvenate the area. Additionally, augmenting the aegyo-sal can also improve
the appearance of dark circles and reduce fine wrinkles due to the skin expansion effect.
When injecting fillers into the aegyo-sal area, it is recommended that the patient
smile first to identify the natural crease formed by the contraction of the lower eyelid
muscle. Care must be taken to avoid adding volume below this line. Typically, a width of
4–6 mm from the subciliary line is appropriate. The filler can be administered to create a
consistent volume along the entire lower eyelid, resembling a roll cake, or the volume can
be strategically varied, with the central portion being the fullest, followed by a slightly less
full outer portion, and the least volume in the inner portion. Some patients may prefer a
slightly thicker appearance towards the lateral third of the eyelid.
The shape and thickness of the aegyo-sal can be customized to the patient’s preferences.
The procedure can be performed using either a needle or a cannula, although a needle is
generally preferred for creating a more precise shape. The challenges of this procedure
include a high likelihood of bruising, the potential for an uneven surface, and the risk of
an unnatural appearance if the area is overfilled. Additionally, because the filler must be
administered in small, controlled amounts, there is a tendency for the aegyo-sal to appear
discontinuous, with gaps or breaks in the contour when viewed as a whole. While the
use of a cannula can mitigate some of these concerns, its manipulation can be challenging,
which is why most practitioners opt for needle-based injections.
4.2. Procedure Method
Aegyo-sal enhancement is recognized as a procedure that can cause considerable
discomfort. Consequently, it is recommended to apply a generous amount of topical
anesthetic ointment to the lower eyelid, covering the area with a wrap for at least , or
alternatively, to perform an infraorbital nerve block prior to the procedure. When utilizing
a needle, it is advisable to opt for a short needle, and typically, a maximum of
0.2–0.4 mL
of filler is injected per side. The practitioner should carefully evaluate the differences
in appearance between a neutral facial expression and a smile to determine the precise
locations and amounts of filler required.
To prevent an uneven or overly prominent appearance, it is preferable to use a soft HA
filler rather than a firm one. Injecting the filler too deeply may result in general puffiness
without achieving the desired plumpness, while injecting too superficially may cause
surface irregularities, such as discontinuous lines or localized protrusions. Moreover, the
filler may exhibit a bluish tint through the skin, known as the Tyndall effect. If the Tyndall
effect is pronounced, even molding may not correct it, necessitating the dissolution of the
filler and a subsequent attempt at the procedure.
When using a needle, the filler is injected directly into the targeted area of the aegyo-sal.
If using a cannula, a puncture point is created a few millimeters outside the lateral canthus,

Life 2025,15, 304 12 of 18
and the cannula is inserted following the needle puncture. The procedure is typically
performed in stages, beginning with the central portion, followed by the lateral and medial
areas. The filler is injected gradually and gently, employing techniques such as retrograde
tiny injection, linear threading, and tenting to achieve a smooth and natural-looking volume
enhancement (Supplement Video S1, Figure 13, and Table 1).
Life 2025, 15, x FOR PEER REVIEW 13 of 19
Figure 13. Injection techniques for the cannula or needle. Linear threading, retrograde tiny injection,
very slow release, serial puncture, and tenting technique.
The author favors a dual-plane technique for achieving the desired pretarsal fullness
(aegyo-sal). This method involves initially injecting filler beneath the orbicularis oculi
muscle or within the superficial layer of the muscle to establish the overall shape. After
the primary contour is formed, any areas that appear deficient or lack sufficient volume
are further refined by injecting additional filler into the dermal or subdermal layers to
smooth the surface and ensure a natural appearance (Figure 14).
Figure 14. Injection planes: Deep subdermal or supramuscular injections. Subdermal injection to
smooth the surface, close to the eyelash.
When using a cannula for this procedure, the entry point should be positioned along
the outer edge of the desired pretarsal fullness, as close to the lower eyelashes as possible,
to avoid creating an unnatural appearance lower on the eyelid. The cannula is then in-
serted, keeping it close to the lower eyelashes and advancing it within the muscle or a
slightly shallower layer. Once the cannula tip reaches the target area, filler is slowly in-
jected while maintaining consistent pressure, gradually retracting the cannula to ensure
an even distribution and uniform shape of the aegyo-sal.
Figure 13. Injection techniques for the cannula or needle. Linear threading, retrograde tiny injection,
very slow release, serial puncture, and tenting technique.
Table 1. Summary of techniques for supraorbital hollowness and pretarsal fullness (aegyo-sal) treatments.
Treatment Area Technique Details Safety Considerations Amount
Supraorbital
Hollowness
Retrograde linear
threading and slow
injection using
small-particle HA filler
Patient in upright position,
injections within preseptal and
sub-orbicularis fat pads;
maintains natural eyelid contour
Avoid injecting within
orbicularis oculi muscle; use
cannula near critical vascular
structures to prevent
complications
0.2–1 cc
Flat Eyebrows
Submuscular injection
into ROOF
(retro-orbicularis oculi
fat) using a cannula
Focus on the area lateral to
midpupillary line; soft filler
injected to smooth surface
Avoid injecting near central
retinal artery connections;
ensure consistent depth
0.2–1.5 cc
Pretarsal Fullness
(Aegyo-sal)
Dual-plane technique
with filler injection
beneath and within the
orbicularis oculi muscle
Positioned close to the lower
eyelashes, gradual injection into
sections (central, lateral,
and medial)
Avoid overly superficial
injection to prevent lumps;
maintain consistent depth to
avoid vascular injury
0.3–1 cc
The author favors a dual-plane technique for achieving the desired pretarsal fullness
(aegyo-sal). This method involves initially injecting filler beneath the orbicularis oculi
muscle or within the superficial layer of the muscle to establish the overall shape. After the
primary contour is formed, any areas that appear deficient or lack sufficient volume are
further refined by injecting additional filler into the dermal or subdermal layers to smooth
the surface and ensure a natural appearance (Figure 14).
When using a cannula for this procedure, the entry point should be positioned along
the outer edge of the desired pretarsal fullness, as close to the lower eyelashes as possible,
to avoid creating an unnatural appearance lower on the eyelid. The cannula is then inserted,
keeping it close to the lower eyelashes and advancing it within the muscle or a slightly

Life 2025,15, 304 13 of 18
shallower layer. Once the cannula tip reaches the target area, filler is slowly injected
while maintaining consistent pressure, gradually retracting the cannula to ensure an even
distribution and uniform shape of the aegyo-sal.
Life 2025, 15, x FOR PEER REVIEW 13 of 19
Figure 13. Injection techniques for the cannula or needle. Linear threading, retrograde tiny injection,
very slow release, serial puncture, and tenting technique.
The author favors a dual-plane technique for achieving the desired pretarsal fullness
(aegyo-sal). This method involves initially injecting filler beneath the orbicularis oculi
muscle or within the superficial layer of the muscle to establish the overall shape. After
the primary contour is formed, any areas that appear deficient or lack sufficient volume
are further refined by injecting additional filler into the dermal or subdermal layers to
smooth the surface and ensure a natural appearance (Figure 14).
Figure 14. Injection planes: Deep subdermal or supramuscular injections. Subdermal injection to
smooth the surface, close to the eyelash.
When using a cannula for this procedure, the entry point should be positioned along
the outer edge of the desired pretarsal fullness, as close to the lower eyelashes as possible,
to avoid creating an unnatural appearance lower on the eyelid. The cannula is then in-
serted, keeping it close to the lower eyelashes and advancing it within the muscle or a
slightly shallower layer. Once the cannula tip reaches the target area, filler is slowly in-
jected while maintaining consistent pressure, gradually retracting the cannula to ensure
an even distribution and uniform shape of the aegyo-sal.
Figure 14. Injection planes: Deep subdermal or supramuscular injections. Subdermal injection to
smooth the surface, close to the eyelash.
For needle injections, the area is typically divided into three sections, with filler injected
into each section to create the overall shape, followed by the addition of small amounts to
any areas that still appear lacking. Even when dividing the area for injections, it is crucial
to maintain a consistent depth throughout the procedure. The filler should be injected as
close to the lower eyelid margin as possible, and the injection plane should be within or just
below the orbicularis oculi muscle to minimize the risk of damaging the inferior palpebral
arterial arch.
Inserting the needle too deeply can pose a risk of injuring the inferior palpebral
arterial arch, which runs beneath the orbicularis oculi muscle, and potentially injecting filler
directly into this vessel. This significantly increases the risk of complications. Therefore,
maintaining a consistent depth during the procedure is essential to ensure the needle tip
does not penetrate below the muscle layer.
The inferior palpebral arterial arch is formed by the anastomosis of the medial palpe-
bral artery, which branches from the supratrochlear artery on the medial side of the orbit,
and the lateral palpebral artery, which branches from the lacrimal artery on the lateral side.
These arteries are components of the superior and inferior palpebral arterial arches. The
significance of this vascular structure lies in its origin: the supratrochlear and lacrimal
arteries are branches of the ophthalmic artery, which itself branches from the internal
carotid artery. If filler is inadvertently injected into the inferior palpebral artery, there is
a risk of retrograde flow, which could allow the filler to travel through these vessels and
reach the central retinal artery, potentially leading to blindness [44].
Given that the inferior palpebral artery is located deep beneath the orbicularis oculi
muscle, injecting the filler within or slightly superficial to the muscle can help minimize the
risk of vascular complications. Additionally, injecting as close to the lower eyelid margin
as possible, considering the pathway of these vessels, enhances the safety of the procedure
(Figure 15).
During the procedure, it is critical to inject the filler as close to the eyelashes as possible
to avoid an excessively thickened appearance below the eyelashes, which would leave
the area near the lashes too hollow. To prevent the filler from migrating downward, the
non-dominant hand should support the tissue beneath the injection site. It is also important
to assess the presence and degree of bulging orbital fat under the eyes before the procedure,

Life 2025,15, 304 14 of 18
as this can cause the lower eyelid and filler-enhanced area to appear excessively swollen
when the patient smiles.
Life 2025, 15, x FOR PEER REVIEW 14 of 19
For needle injections, the area is typically divided into three sections, with filler in-
jected into each section to create the overall shape, followed by the addition of small
amounts to any areas that still appear lacking. Even when dividing the area for injections,
it is crucial to maintain a consistent depth throughout the procedure. The filler should be
injected as close to the lower eyelid margin as possible, and the injection plane should be
within or just below the orbicularis oculi muscle to minimize the risk of damaging the
inferior palpebral arterial arch.
Inserting the needle too deeply can pose a risk of injuring the inferior palpebral arte-
rial arch, which runs beneath the orbicularis oculi muscle, and potentially injecting filler
directly into this vessel. This significantly increases the risk of complications. Therefore,
maintaining a consistent depth during the procedure is essential to ensure the needle tip
does not penetrate below the muscle layer.
The inferior palpebral arterial arch is formed by the anastomosis of the medial pal-
pebral artery, which branches from the supratrochlear artery on the medial side of the
orbit, and the lateral palpebral artery, which branches from the lacrimal artery on the lat-
eral side. These arteries are components of the superior and inferior palpebral arterial
arches. The significance of this vascular structure lies in its origin: the supratrochlear and
lacrimal arteries are branches of the ophthalmic artery, which itself branches from the in-
ternal carotid artery. If filler is inadvertently injected into the inferior palpebral artery,
there is a risk of retrograde flow, which could allow the filler to travel through these ves-
sels and reach the central retinal artery, potentially leading to blindness [44].
Given that the inferior palpebral artery is located deep beneath the orbicularis oculi
muscle, injecting the filler within or slightly superficial to the muscle can help minimize
the risk of vascular complications. Additionally, injecting as close to the lower eyelid mar-
gin as possible, considering the pathway of these vessels, enhances the safety of the pro-
cedure (Figure 15).
Figure 15. Anatomy of the superior and inferior palpebral arteries.
During the procedure, it is critical to inject the filler as close to the eyelashes as pos-
sible to avoid an excessively thickened appearance below the eyelashes, which would
leave the area near the lashes too hollow. To prevent the filler from migrating downward,
the non-dominant hand should support the tissue beneath the injection site. It is also im-
portant to assess the presence and degree of bulging orbital fat under the eyes before the
Figure 15. Anatomy of the superior and inferior palpebral arteries.
Filler injection for enhancing pretarsal fullness (aegyo-sal) is not recommended in
certain cases. These include situations where the eyelid roll muscle is underdeveloped,
the eye fissure (palpebral fissure) is either too wide or too narrow, the outer corners of the
eyes are significantly elevated or lowered, the eyes are excessively sunken or protruding,
the lower eyelid skin is too thick, there is severe darkening under the eyes, significant
skin laxity is present, or there is pronounced bulging of the lower eyelid fat. Additionally,
patients with scars from previous lower eyelid surgeries may encounter challenges with
this procedure, making it difficult to achieve a natural-looking result.
For patients who have undergone lower eyelid surgery, creating pretarsal fullness can
enhance their appearance, but it requires careful consideration due to potential scarring.
If scarring has caused the eyelashes to invert or become misaligned, it is advisable to
avoid the procedure altogether. In cases where scarring is not severe, it is possible to
proceed by injecting the filler close to the eyelashes. However, starting with a deep injection
can cause the filler to bypass the scarred area, leading to an uneven result where the
scarred region remains flat. Therefore, it is recommended to begin with a shallow injection,
gradually increasing the depth based on the observed contour, to achieve a balanced and
natural appearance.
In patients who have undergone lower eyelid surgery, the initial filler injection may
result in an uneven appearance due to adhesions caused by surgical scars, leading to
irregular filler distribution. However, over the course of 1–2 weeks, as the patient naturally
opens and closes their eyes, the filler typically disperses and settles into a more uniform
contour. If the irregularities persist after this period, minor depressions can be improved
by using a fine needle to inject a very soft, small-particle filler, which can help smooth out
the surface and achieve a more even appearance.
5. Results
In this study, we identified key anatomical layers within the supraorbital and pre-
tarsal regions essential for achieving natural, safe filler augmentation. An analysis of
these layers allowed for targeted recommendations regarding filler placement to minimize

Life 2025,15, 304 15 of 18
complications and improve aesthetic outcomes. Supraorbital hollowness correction was
best achieved with injections within the preseptal or sub-orbicularis oculi fat pads, while
pretarsal fullness augmentation was most effective when fillers were placed close to the lash
line to achieve the desired “charming roll” effect. The use of cannulas rather than needles in
areas near critical vascular structures, such as the supratrochlear and supraorbital arteries,
was emphasized to enhance safety by reducing the risk of vascular complications.
Through a comprehensive review of recent studies on filler applications in East Asian
populations, we found that cultural aesthetic preferences significantly impact the preferred
filler techniques, particularly for pretarsal fullness, commonly known as aegyo-sal among
Koreans. Pretarsal augmentation was found to be particularly popular, as it enhances
the youthful appearance of the eyes without altering natural contours. Additionally,
a comparison of synthetic fillers with autologous fat transfer revealed that, while both
approaches are effective, hyaluronic acid fillers provide a less invasive and reversible option
with minimal recovery time, while fat transfer offers a more durable result for patients
seeking a long-term correction of volume loss.
6. Discussion
The correction of supraorbital hollowness and enhancement of pretarsal fullness
(commonly known as aegyo-sal) requires precision, particularly when addressing these
areas in East Asian populations where specific anatomical features, such as reduced at-
tachment of the levator muscle and unique fat distribution, impact aesthetic outcomes.
Hyaluronic acid (HA) fillers are widely used for these enhancements because they provide
a controlled, minimally invasive way to add volume, are reversible with hyaluronidase,
and are associated with minimal recovery time. When injected at appropriate anatomical
planes—particularly within the preseptal and sub-orbicularis fat pads—HA fillers can
correct supraorbital hollowness while avoiding the complications often associated with
superficial injections or intra-muscular placement, such as bruising or migration of the
filler. In addition to synthetic fillers, autologous fat transfer, or lipofilling, serves as an
effective alternative for volume restoration. Lipofilling utilizes the patient’s own fat, har-
vested through liposuction from areas such as the abdomen or thighs, and reinjected into
the target site after processing. This technique offers distinct advantages, particularly for
patients with pronounced volume deficits or those seeking a more permanent result. Fat
transfer is associated with natural-looking, long-lasting effects due to the potential for the
transferred fat cells to integrate and persist in the new site.
The study of Julieta et at. reviewed supraorbital anatomy, etiology, and pathophysiol-
ogy, introducing a new classification for sunken upper eyelid and a low-risk filler technique
using high-cohesivity hyaluronic acid. Thirty-two adults, predominantly female and
without prior fillers, received HA injections in a two- or three-visit protocol, with results
assessed across a year. Patients showed natural results without significant swelling, and
only one required correction with hyaluronidase. Overall, the long-lasting and safe results
suggest that cohesive HA is an effective, patient-satisfying option for non-surgical SUE
treatment [1].
Supraorbital hollowness and flat eyebrows are interrelated conditions that significantly
impact facial aesthetics, especially in East Asian populations. Supraorbital hollowness,
characterized by a sunken appearance of the upper eyelid, is primarily influenced by genetic
factors, aging, and sometimes surgical interventions such as blepharoplasty. The natural
loss of fat in the orbital region, combined with anatomical variations like weaker or absent
connections of the levator palpebrae superioris muscle to the dermal tissue, contributes
to the sunken, tired look often seen in older adults [
2
,
3
,
45
–
50
]. This condition is further
accentuated by the descent of subcutaneous fat and changes in the surrounding eyebrow

Life 2025,15, 304 16 of 18
region, creating a compound effect that alters the appearance of the entire periorbital
area. Flat or drooping eyebrows exacerbate this hollow look by creating an unbalanced
appearance that draws attention to the upper eyelid, emphasizing the signs of aging or
fatigue [16,17].
The treatment of supraorbital hollowness requires a precise and careful approach to
restore volume and achieve a more youthful contour. Injecting hyaluronic acid (HA) fillers
into the appropriate layers of tissue can significantly improve the sunken appearance of
the upper eyelid. However, the selection of the correct injection plane is critical to avoid
complications such as hemorrhage, hematoma formation, or vascular compromise. Using a
cannula instead of a needle can reduce the risk of intra-arterial injection, particularly around
critical vascular structures like the supratrochlear and supraorbital arteries. Enhancing the
orbital rim’s hollow areas can soften the prominent supratarsal lid crease and improve the
overall eyelid contour, making the eyes appear more alert and rejuvenated. Nevertheless,
achieving optimal results necessitates a comprehensive understanding of the anatomical
variations and potential risks involved in the treatment of this delicate area [51].
Addressing flat eyebrows involves not just volumizing but also reshaping to restore
their natural arch and position, which plays a pivotal role in overall facial aesthetics. The
position and shape of the eyebrows influence the perception of youthfulness and emo-
tional expressiveness. With age, the volume loss in the retro-orbicularis oculi fat (ROOF)
and surrounding areas causes the eyebrows to sag, further contributing to an aged ap-
pearance [
52
–
55
]. By restoring volume to the eyebrow region, particularly lateral to the
midpupillary line, and refining the shape through careful filler placement, practitioners
can lift the eyebrows and enhance their natural contours. This approach not only im-
proves the appearance of the eyebrows but also complements the correction of supraorbital
hollowness, providing a balanced and harmonious rejuvenation of the upper face. A well-
considered treatment plan that addresses both supraorbital hollowness and flat eyebrows
can significantly enhance the patient’s overall appearance, creating a more vibrant and
youthful look.
Supplementary Materials: The following supporting information can be downloaded at: https://www.
mdpi.com/article/10.3390/life15020304/s1, Video S1: Anatomy-Based Filler Injection: Treatment
Techniques for Charming Roll.
Author Contributions: Conceptualization, G.-W.H., K.-H.Y., J.W. and W.C.; Writing—Original Draft
Preparation, G.-W.H., J.W., C.B., L.B., S.E.Y. and P.L.; Writing—Review and Editing, G.-W.H. and
K.-H.Y.; Visualization, G.-W.H. and K.-H.Y.; Supervision, G.-W.H. and K.-H.Y. All authors have read
and agreed to the published version of the manuscript.
Funding: This research received no external funding.
Conflicts of Interest: Author Jovian Wan was employed by the Medical Research Inc. The remaining
authors declare that the research was conducted in the absence of any commercial or financial
relationships that could be construed as a potential conflict of interest.
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