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AIM: To study the outcomes of ReLExⓇ small incision lenticule extraction (SMILE) for correction of myopia or myopic astigmatism in terms of visual acuity, contrast sensitivity, aberrations, and dry eye. METHODS: In this prospective, non-randomized clinical study, done at Nethradhama Super Speciality Eye Hospital, a total of 600 eyes that met the inclusion criteria underwent a thorough preoperative examination, including corrected distance visual acuity (CDVA), contrast sensitivity, aberrometry, and dry eye assessment. VisuMax femtosecond laser system was used to perform SMILE. Patients were followed up on 1, 15d and 3mo. Pre and postoperative uncorrected visual acuity (UCVA), CDVA, aberrations, dry eye, and contrast sensitivity during 3mo of follow-up were recorded. Data analysis was done with the help of a computer using SPSS for Windows Software (version 17.0, SPSS, Inc., New York, USA). A paired t-test was used to test the significance of difference between quantitative variables and Yate's Chi-square test for qualitative variables. P value less than 0.05 denoted a significant relationship. RESULTS: The study enrolled 600 eyes of 305 patients, of which 10 patients underwent SMILE in 1 eye only due to anisometropia. At 3mo, 98.83% of eyes had attained a UCVA of 20/20 or better. No patient had a loss of CDVA, and 37 eyes (6.17%) showed a gain in 1 line in postoperative CDVA. Postoperative induction of coma and spherical aberrations was minimal. Contrast sensitivity reduced immediate postoperatively (P<0.001) but showed improvement by 3mo, especially at lower spatial frequencies (P=0.43, 0.47, 0.46) CONCLUSION: Our results demonstrate the high refractive accuracy and safety of ReLExⓇ SMILE for the treatment of myopia and myopic astigmatism. Increase in postoperative dryness and aberrations, both accepted drawbacks of any corneal refractive surgery were observed, while decrease in contrast sensitivity was insignificant at lower spatial frequencies.
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·Original article·
Visual and refractive outcomes with ReLExSMILE in
600 eyes
Sri Ganesh1, Rishika Gupta2
1Chairman and Managing Director, Nethradhama Super
Speciality Eye Hospital, Bangalore 560082, India
2Department of Ophthalmology, Nethradhama Super Speciality
Eye Hospital, Bangalore 560082, India
Correspondence to: Rishika Gupta. Nethradhama Super
Speciality Eye Hospital, 256 / 14, Kanakpura Main Road, 7th
block Jayanagar, Bangalore 560082, India. rishikagupta55@
yahoo. com
Received: 2015-03 -24 Accepted: 2015-08 -20
ReLEx飞秒激光微小切口基质透镜取出术治疗
近视或近视散光术后屈光情况研究
Sri Ganesh1,Rishika Gupta2
(作者单位:1印度,班加罗尔 560082,Nethradhama 超级专业眼科
医院人事管理部;2,加罗 560082, Nethradhama 超级
业眼科医院眼科)
通讯作者:Rishika Gupta. rishikagupta55@ yahoo. com
摘要
目的:究分析采用 ReLEx全飞秒激光微小切口基质透
镜取出(SMILE)治疗近视或近视散光术后视力对比敏
感度像差及干眼发生情况
方法:瞻性非随机临床研收集符合研究标准的 600
眼接受全面眼科检查,包括矫正远视力对比敏感度像差
和干眼 SMILE VisuMax 全飞秒激光系统
术后 1,15d 3mo 对患者进行随访,并记录术前和术后
3mo 内的裸眼视力矫正远视力像差干眼和对比敏感
数据分析采用 SPSS(,17. 0 )计量资
料采用配对 t检验统计,计数资料采用 Yate 卡方检验统
。 P<0. 05 则差异有统计学意义
结果:研究包305 (600 )患者其中,10 位患者
由于屈光参SMILE3mo,98. 83 %
裸眼视力达20 / 20所有患者矫正远视力无下
降并且 有 37 (6. 17% )提高了一行后产生的彗差
球面像差最小术后早期对比敏感度减少( P< 0. 01) ,
3mo 后增加,特别是低频尤为明显( P = 0. 430. 47 0. 46)
结论:果表明,ReLExSMILE 治疗近视和近视散光
安全,与其他屈光手术一样,术后干眼和像差有所增,
低频对比敏感度的下降不明显
关键词:ReLEx微小切口基质透镜取出术;激光;
视矫正;屈光结
引用:Ganesh S, Gupta R. ReLEx飞秒激光微小切口基质透镜
取出术治疗近视或近视散光术 屈光 况研 .际眼 杂志
2016;16(2 ) :218-223
Abstract
AIM:To study the outcomes of ReLExsmall incision
lenticule extraction (SMILE)for correction of myopia or
myopic astigmatism in terms of visual acuity,contrast
sensitivity,aberrations,and dry eye.
METHODS:In this prospective,non-randomized clinical
study,done at Nethradhama Super Speciality Eye
Hospital,a total of 600 eyes that met the inclusion criteria
underwent a thorough preoperative examination,
including corrected distance visual acuity (CDVA ) ,
contrast sensitivity,aberrometry,and dry eye
assessment. VisuMax femtosecond laser system was
used to perform SMILE. Patients were followed up on 1,
15d and 3mo. Pre and postoperative uncorrected visual
acuity (UCVA ), CDVA,aberrations,dry eye,and
contrast sensitivity during 3mo of follow -up were
recorded. Data analysis was done with the help of a
computer using SPSS for Windows Software (version
17郾 0,SPSS,Inc. ,New York,USA). A paired t-test was
used to test the significance of difference between
quantitative variables and Yate蒺s Chi -square test for
qualitative variables. Pvalue less than 0.05 denoted a
significant relationship.
RESULTS:The study enrolled 600 eyes of 305 patients,
of which 10 patients underwent SMILE in 1eye only due to
anisometropia. At 3mo,98.83% of eyes had attained a
UCVA of 20 /20 or better. No patient had a loss of CDVA,
and 37 eyes (6.17%)showed a gain in 1line in
postoperative CDVA. Postoperative induction of coma and
spherical aberrations was minimal. Contrast sensitivity
reduced immediate postoperatively (P< 0.001 )but
showed improvement by 3mo,especially at lower spatial
frequencies (P= 0.43,0.47,0.46)
CONCLUSION:Our results demonstrate the high
refractive accuracy and safety of ReLExSMILE for the
treatment of myopia and myopic astigmatism. Increase in
postoperative dryness and aberrations,both accepted
drawbacks of any corneal refractive surgery were
observed,while decrease in contrast sensitivity was
insignificant at lower spatial frequencies.
KEYWORDS:ReLExsmall incision lenticule extraction;
femtosecond laser;myopic correction;refractive
outcomes
DOI:10. 3980 / j. issn. 1672 -5123. 2016. 2. 05
Citation:Ganesh S, Gupta R. Visual and refractive outcomes with
ReLExSMILE in 600 eyes. Guoji Yanke Zazhi(Int Eye Sci) 2016;
16(2) :218-223
812
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INTRODUCTION
In the present scenario, photo - refractive keratectomy
( PRK ) and laser - assisted in situ keratomileusis
( LASIK) are the most widely practiced procedures for myopic
correction.
PRK offers the advantage of retaining corneal biomechanical
strength but entails a surface insult to the eye, causing patient
discomfort postoperatively and haze and regression in the long
run[1] . LASIK allows rapid visual rehabilitation and wound
healing, but biomechanically it results in an unstable system.
Until recently, femtosecond lasers have primarily been used as
an alternative to microkeratomes to cut thinner and planar
corneal flaps in LASIK patients, thus enhancing the safety of
correction in thinner corneas[2-3 ] . Even with its high success
rates, side effects such as increased postoperative dryness,
reduced biomechanical corneal strength, induction of higher-
order aberrations ( HOA) , postoperative glare, haloes, and
flap-related complications remain[4 -6] .
More recently developed is therefractive lenticule extraction,
which uses femtosecond laser to correct myopia by creating an
intrastromal corneal lenticule, the removal of which, alters the
shape of the cornea, thereby correcting myopia. It
encompasses two different techniques: femtosecond lenticule
extraction ( FLEX ) and small incision lenticule extraction
(SMILE) .
FLEX, first reported by Sekundo et al[7] in 2008, essentially
mimics a LASIK - type procedure in that it involves the
creation of a flap. The procedure begins with creation of a
deeper plane of lenticule, followed by the superficial cut,
which is extended beyond the limit of the deeper cut to form
the anterior corneal flap. The hinged flap is then lifted above
the lenticule in a similar fashion to the LASIK flap, the
refractive lenticule is peeled away, and the flap is
repositioned.
SMILE is a more recent, flapless subtype, in which the
lenticule is extracted through a small arcuate incision (2 - 4
mm) . This allows for greater stability as most of the Bowman蒺s
layer remains intact. In this paper, we present our clinical
experience with ReLExSMILE performed in 600 eyes.
SUBJECTS AND METHODS
This prospective, non - randomized study included patients
presenting to our hospital for correction of myopia between
Dec. 2013 and May 2014. The study was approved by the
local ethics committee and performed in accordance with the
tenets of the Declaration of Helsinki. Informed consent was
obtained from all patients.
Inclusion criteria were:spherical equivalent up to -10 D, age
of 21y or older, stable refraction for at least 1y, soft contact
lens discontinued for 1wk and rigid gas permeable lens
discontinued for 3wk prior to the procedure, minimum corneal
thickness of 480 滋m, residual stromal bed of at least 250
滋m, ability to understand and willingness to participate in all
follow-up visits.
Exclusion criteria included: evidence of residual or active
ocular diseases such as herpetic keratitis, uveitis, glaucoma,
Table 1摇 Patient Demographics
Number of patients / eyes 305 / 600
Sex
M 125 ( 40. 8% )
F 180 ( 59. 2% )
Age(a) 27. 4依5. 60(18-51)
Sphere(D) -4. 33 依2. 2
Cylinder(D) -1. 03 依0. 87
Spherical equivalent( D) -4. 28 依2. 34
Schirmer蒺s 1 ( mm) 33. 8依2. 00 (26-35)
Schirmer蒺s 2 ( mm) 27. 65依4. 11 (17-34)
TBUT ( s) 12. 29依1. 13 ( 9-14)
Tear osmolarity (mOsm / L) 308. 64依16. 50 (305-311)
RMS HOA total ( 滋m) 0. 258依0. 116 ( 0. 01-0 . 78)
A(1. 5 c / d) 35. 4依5. 9
B (3 c / d) 68. 1依11. 6
C (6 c / d) 75. 2依14. 3
D (12 c / d) 30. 1依2. 2
E (18 c / d) 12. 3依1. 9
visually significant cataract, retinal diseases such as retinal
dystrophies or diabetic retinopathy, corneal dystrophies,
keratoconus, history of corneal trauma or surgery, severe dry
eyes ( Schirmer 2 test value less than 10 mm ) , use of
systemic medications likely to affect wound healing ( e. g.
corticosteroids or antimetabolites), an immuno-compromised
state, or females who were pregnant or nursing.
A thorough preoperative examination was conducted on each
eye including Snellen corrected distance visual acuity
( CDVA) , manifest refraction (sphere, cylinder and spherical
equivalent) ( Table 1 ) , corneal topography ( Orbscan and
Pentacam), functional acuity contrast test ( F. A. C. T ),
Schirmer蒺s 1 and 2, tear breakup time ( TBUT ), tear
osmolarity (TearLab) and aberrometry (iTrace).
Vision Sciences Research Corporation蒺s ( VSRC) patented F.
A. C. T Chart is a sine-wave grating chart that tests 5 spatial
frequencies ( sizes ) and 9 levels of contrast. Tested
monocularly, the patient determines the last grating seen for
each row (A, B, C, D, and E ) . The test is performed at
normal room i llumination (30 - 70 foot lamberts / 68 - 240 cd /
m2) at a distance of 10 feet. Absolute values of contrast
sensitivity were obtained for each patient, and mean and
standard deviation values were then calculated.
Wavefront measurements were taken using the Hoya iTrace-
combination ray - tracing wavefront aberrometer ( Tracey
Technologies Corporation, Houston, Texas, USA) with a 5. 0
mm analysis diameter and included the root mean square
(RMS) HOA: Total, coma, and spherical aberrations. The
iTrace sequentially projects 256 near - infrared laser beams
into the eye to measure forward aberrations. Data is displayed
in the form of wavefront maps showing RMS value for each
aberration.
Patients were given a subjective questionnaire on 1d to assess for
any pain, pricking sensation, watering and redness and at 15d to
912
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assess glare and overall patient satisfaction. The level of pain
was assessed using the Wong- Baker faces pain rating scale.
Patients either indicated “ yes 冶 or “ no 冶 for the presence or
absence of pricking sensation, watering, and redness. Patient
satisfaction was measured on a scale of 1 ( excellent) to 4
(poor) , and glare was graded on a scale of 0 (no difficulty)
to 4 ( severe difficulty) .
ReLExSMILE Procedure摇 ReLExSMILE was performed
using VisuMax femtosecond laser (Carl Zeiss Meditec, Jena,
Germany). The following parameters were used: 100 滋m cap
thickness, 7. 5 mm cap diameters, 6 . 0 - 6 . 5 mm optical
zone, 500 kHz repetition rate, 35 - 37 ( 130 nJ ) energy cut
index, a 2 mm side cut incision, and 4. 5 滋m spot and track
distance.
Patient was positioned under the curved contact glass of the
femtosecond laser and asked to fixate on a blinking target.
When appropriate centration was achieved, suction was
applied and laser started. Following creation of the lenticule,
incision was opened, and the two planes of the lenticule were
identified. A thin blunt spatula was used to dissect the
superficial and deep planes of the lenticule and to break the
remaining tissue bridges, thus separating the lenticule from
the surrounding stroma. This lenticule was grasped with a pair
of forceps and extracted through the 2 mm incision.
The corneal interface was then flushed with balanced salt
solution. Postoperative regimen included prednisolone
acetate, ofloxacin and lubricating eyedrops.
Follow-up Follow - up visits were on 1 , 15d and 3mo.
UCVA, CDVA, and refraction was tested on 1d, corneal
topography, wavefront measurement ( iTrace, Hoya ) ,
Schirmer 1, 2, TBUT, and TearLab and F. A. C. T for
contrast sensitivity was tested at 15d and at 3mo.
Data Collection and Statistical Analysis Data analysis was
done with the help of a computer using SPSS for Windows
Software ( version 17. 0, SPSS, Inc. , New York, USA) .
Using this software, range, frequencies, percentages, means,
standard deviations, Chi square and Pvalues were calculated.
A paired t-test was used to test the significance of difference
between quantitative variables and Yate蒺s Chi - square test for
qualitative variables. Pvalue less than 0. 05 denoted a
significant relationship.
RESULTS
Six hundred eyes of 305 patients underwent SMILE for
correction of myopia and / or myopic astigmatism. One hundred
and twenty five ( 40 . 8% ) patients were male and 180
(59郾 2% ) were female (Table 1). Patients were between 21
and 51y of age (mean age: 27. 4 5. 6 y).
Refraction Preoperative mean spherical equivalent was -4. 28依
2. 34 D ( range: - 0. 50 D to - 10 . 0 D; Table 1 ) .
Postoperative mean spherical equivalent was -0. 14 依 0 . 28 D
(range: -0. 12 D to -0. 75 D) .
Refractive Efficacy Postoperatively, at 1d, 47 eyes
(7郾 83% ) achieved a UCVA of 20 / 25 or better, 536 eyes
(89. 33% ) achieved 20 / 20 and, 17 eyes (2. 83% ) achieved
20 / 15.
Figure 1 摇 Cumulative percentages of eyes in which target
refraction was zero attaining specified levels of uncorrected
distance visual acuity (UDVA )3mo after small -incision
lenticule extraction (SMILE).
Figure 2摇 The percentage of eyes (y-axis)in which there was
a gain / loss of specified number of Snellen visual acuity lines
3mo after SMILE.
At 3mo postoperatively, 7 eyes ( 1. 17 % ) achieved a UCVA
of 20 / 25, 556 eyes (92. 67% ) had achieved a UCVA of 20 /
20, and 37 eyes (6 . 17% ) had achieved 20 / 15 ( Figure 1 ).
Safety On 1d postoperatively, 40 eyes ( 6. 67% ) showed
loss of 1 line in CDVA, 543 eyes ( 90. 5% ) showed no
difference between preoperative CDVA and postoperative
CDVA, and 17 eyes ( 2 . 83 % ) showed a 1 - line gain in
CDVA. By 15d, 10 eyes (1. 67% ) showed loss of 1 line in
CDVA, 561 eyes (93. 5% ) had no difference, and 29 eyes
(4. 83% ) showed a gain of 1 line. By 3mo, 37 eyes
(6郾 17% ) showed a gain of 1 line, while 563 eyes (93. 8% )
showed no change. No eye had a loss of CDVA at 3mo
postoperatively ( Figure 2) .
Predictability A scatter plot of the attempted correction
versus the actual correction achieved ( manifest spherical
equivalent) at 3 mo after SMILE is shown in Figure 3. All
patients were within 依0 . 75 D of the attempted correction.
At 3 mo after surgery, 93 . 17% (559) of eyes were within -
0. 14 D to -0. 50 D, 6. 17% (37 eyes) were within -0. 13 to
+0. 13D, and 0. 67% (4 eyes) were within -0. 50 to-1. 00D
of the attempted correction (Figure 4).
Contrast Sensitivity Contrast sensitivity reduced
postoperatively at all spatial frequencies ( P< 0. 001 ) . An
improvement was observed in the absolute values of contrast
sensitivity from 1d to 15d and from 15d to 3mo
postoperatively, particularly at lower spatial frequencies ( P=
0. 43, 0. 47, 0 . 46) (Figure 5).
022
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Figure 3 摇 Predictability:the scatter plot of the attempted
versus the actual manifest spherical equivalent correction 3mo
after SMILE (600 eyes).
Figure 4摇 Percentage of eyes within different diopter ranges of the
attempted correction (spherical equivalent)3mo after SMILE.
Figure 5 摇 The preoperative and 3mo postoperative FACT
contrast sensitivity following SMILE.
Corneal Wavefront HOA increased from a preoperative
mean RMS ( Table 1) of 0. 258 0. 116滋m ( range: 0 . 011 to
0. 78 滋m) to 0. 36 0. 109 滋m at 15 d and 0. 31 依0. 115 滋m
3mo postoperatively ( P<0. 001; Figure 6). A 0. 03 滋m and
0. 08 滋m increase in mean coma and spherical aberrations was
observed.
Dry Eye A significant reduction in Schirmer蒺s 1 and 2 and
TBUT were seen from a preoperative mean (Table 1) of 33. 8
2 mm, 27. 65 4. 1 mm, and 12. 29 依 1. 13s to a
postoperative mean of 32. 67 依2. 28 mm, 24. 59 依2. 65 mm,
and 10. 4 1. 24s respectively at 3 mo ( P<0. 001) . Similarly,
TearLab significantly increased from 308. 64 依16. 5 mOsm / L
to 309. 37 17. 2 mOsm / L ( P<0. 001; Figure 7).
Figure 6 摇 Preoperative and postoperative higher order
aberrations following SMILE.
Figure 7The preoperative and postoperative tear osmolarity
(mOsm / L )following SMILE.
Patient Questionnaire The mean score on the subjective
questionnaire on pain, redness, watering, pricking sensation
was 0. 21依 0. 36. Patient satisfaction score was 3. 57 依0. 41.
Score for glare complaints was 1. 89依0. 73.
Complications During the procedure, 5 eyes ( 0. 833% )
experienced suction loss. Four suction breaks were corrected
by redocking and reapplying the laser. The fifth eye
experienced suction loss before the deeper plane of the
lenticule was cut and hence could not be re-docked. A flap
had to be created in this eye using the VisuMax femtosecond
laser, and the eye was treated with excimer laser ablation for
correction of refractive error. This eye was excluded from the
study as the eye underwent a flap procedure similar to the one
seen in LASIK rather than SMILE.
DISCUSSION
To date, LASIK has been considered the “gold standard冶 for
laser refractive correction of myopia, with flaps fashioned in
more than 50% of cases with the femtosecond laser, according
to a 2009 industry survey[8] . Various studies have been
published about limitations of LASIK. It is estimated that the
incidence of corneal ectasia following LASIK surgery ranges
between 0. 2-0. 6% [9- 10] . Other drawbacks such as increased
postoperative dryness, reduced biomechanical corneal
strength, induction of HOA causing postoperative glare,
haloes, and flap-related complications remain[4- 6] .
So far, relatively little is known about the refractive outcomes,
contrast sensitivity, aberrations, and dry eyes in a large
sample size of SMILE patients.
Vestergaard et al[11] found that 95% patients attained a UCVA
of 20 / 40 or better 3mo following ReLExSMILE, while 2
eyes showed a gain of 2 lines of CDVA at 3 mo. Hjortdal et
al[ 12] found that 97 . 2 % patients achieved a UCVA of 20 / 40
or better at 3mo following SMILE. In our study, 98. 83% of
122
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the eyes (593 eyes ) achieved a UCVA of 20 / 20 or better.
Results of SMILE are better than those found in literature for
PRK. Two long-term studies of PRK have shown that between
50. 7 % and 67 % of eyes achieve a UCVA of 20 / 20 or
better[13 -14] . In a comparative study, Hu et al[15] found 48
eyes showing a gain of 1 line in SMILE group, and 37 eyes in
LASIK group. No patient in SMILE group showed loss of
CDVA while 1 eye in LASIK group had loss of CDVA by 1
line. In our study, no eye had loss of CDVA. By 3mo, 37
eyes ( 6 . 17 % ) showed a gain of 1 line, while 563 eyes
(93郾 8% ) showed no change in CDVA.
We believe this is because refractive accuracy depends on the
accurate removal of stromal tissue intraoperatively. A variation
in hydration of the corneal stroma is the most likely cause for
under- or overablation of stromal tissue[ 16-18] . In LASIK, the
flap needs to be lifted before excimer laser ablation can be
performed. This exposes the stroma to hydration changes
before refractive correction. On the other hand, in SMILE,
refractive lenticule is cut by femtosecond laser prior to any
disturbance of the stroma, thus enhancing the procedure蒺s
predictability.
Increase in corneal HOA postoperatively was statistically
significant ( P< 0. 01) which can be attributed to a larger
sample size ( n= 600 ) and lower standard deviation. We
found a 0. 03 滋m and 0. 08 滋m increase in mean coma and
spherical aberrations. Similar results were reported by Shah et
al[ 19] where in increase in mean coma and spherical
aberrations was 0 . 07 滋m and 0. 11 滋m, respectively.
A comparison of our results with those available in the
literature for LASIK shows fewer aberrations induced
postoperatively following SMILE compared with LASIK.
Studies done on LASIK byde Orteuta et al[ 20] showed an
increase of 0. 10 滋m in coma and 0. 17 滋m in spherical
aberrations. Kohnen et al[ 21] found an increase of 0. 13 滋m in
spherical aberrations.
Decentration of ablation intraoperatively can lead to induction
of coma postoperatively. However, low suction pressure
during SMILE enables the patient to see the blinking target,
thereby allowing a good and steady centration. This could be
the reason for the low RMS coma induced postoperatively.
With regard to contrast sensitivity, Sekundo et al[22] in a study
on SMILE, found no significant decrease in mesopic contrast
postoperatively, while in another comparative study between
ReLExand FS - LASIK, Gertnere et al[ 23] found better
mesopic contrast sensitivity in ReLExgroup than LASIK
group. Mont伢s -Mic佼 et al[ 24] found a statistically significant
reduction ( P< 0. 01 ) in contrast sensitivity at high spatial
frequencies ( 12 and 18 c / d ) under mesopic conditions
following LASIK. In the present study, a significant reduction
in contrast sensitivity was observed at postoperative 1d ( P<
0郾 001 ), but that improved by 15d and by 3mo
postoperatively and was clinically insignificant for lower
spatial frequencies ( 1. 5 , 3, and 6 c / d) ( P= 0. 43, 0. 47,
0. 46) .
Postoperative dry eye following ReLExSMILE was seen with
less frequency than that seen following PRK or LASIK[ 25-26] .
This can be attributed to the small side - cut incision,
approximately one-eighth the length of a LASIK flap, which
means a smaller likelihood of cutting corneal nerves, hence
leading to less dry eye postoperatively.
Adverse event was noted only in 1 out of 5 eyes that
experienced suction loss intraoperatively. SMILE procedure
had to be abandoned and conversion to flap, followed by
excimer laser for correction of refractive error was done. In the
study done by Shah et al[ 19] 1 eye incurred suction loss
intraoperatively. Postoperatively, 5 eyes showed corneal cap
edema, which resolved subsequently. Perioperative
complications noted by Ivarsen et al[ 27] in a study of 1500
eyes which underwent SMILE, included epithelial abrasions
(6% ) , small tears at the incision (1. 8 % ), and difficult
lenticule extraction (1. 9% ) . Cap perforation in 4 eyes, and
a major tear in 1 eye was noted.
ReLExSMILE is the most significant development in corneal
refractive surgery since the introduction of LASIK. In the
hands of experienced surgeons, the ReLExSMILE technique
provides the combined advantages of LASIK and PRK with a
minimal risk of complications. Our results demonstrate high
refractive accuracy, predictability, safety and patient
satisfaction associated with ReLExSMILE.
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Article
AIM: To compare the postoperative visual outcomes of VisuMax small incision lenticule extraction (SMILE) and femtosecond laser assisted LASIK (FEMTO LASIK) for myopia. METHODS: Eighty-tree eyes (42 patients) underwent VisuMax SMILE and 94 eyes (47 patients) received FEMTO LASIK to correct myopia were comprised. The safety, efficacy, predictability, stability and adverse events were assessed preoperatively and 1d, 1 week, 1 month, 3 months postoperatively. RESULTS: At 3 months, the mean safety index was 1.10±0.16 in the SMILE group and 1.09±0.16 in the FEMTO LASIK group; the mean efficacy index was respectively 1.10±0.16 and 1.08±0.12; Spherical equivalent (SE) was respectively 0.11±0.23D and 0.08±0.25D within ±1.00D of the targeted SE correction in 82 eyes (98.8%) of the SMILE group and 91 eyes (96.8%) of the FEMTO LASIK group and SE within ±0.50D in 73 eyes (88.0%) of the SMILE group and 78 eyes (83.0%) of the FEMTO LASIK group. There were no significant complications in both groups. CONCLUSION: SMILE and FEMTO LASIK have equal safety, efficacy, predictabilityand stability in the treatment of myopia.
Article
To report one year results of the first cohort of routine refractive lenticule extraction through a small incision (ReLEx SMILE) for correction of myopia and myopic astigmatism. Fifty-four eyes of 27 patients with spherical equivalent of -4.68 ± 1.29D who underwent routine ReLEx SMILE by a single surgeon were prospectively followed-up for 1 year. We used the VisuMax® femtosecond laser system (Carl Zeiss Meditec AG, Germany) with a 500 kHz repetition rate. Folow-up intervals were at 1 day, 1 week, 1, 3, 6, and 12 months after surgery. We obtained following parameters: uncorrected (UDVA) and distance-corrected visual acuity (CDVA), contrast sensitivity, and wave front measurements. We also recorded all complications. Because of suction loss in one eye, 12-month results were obtained in 53 eyes as follows. After 1 year, 88 % of eyes with plano target had an UDVA of 20/20 or better. Twelve percent of eyes lost 1 line of CDVA, while 31 % gained 1 line and 3 % gained 2 lines. The mean SE after 1 year was -0.19 ± 0.19. The mean refraction change between month 1 and 12 was 0.08 D. Neither mesopic nor photopic contrast sensitivity showed any significant changes. The high-order aberrations (HOA) increased from 0.17 to 0.27 μm (Malacara notation). No visually threatening complications were observed. In this first cohort, ReLEx® SMILE produced satisfactory refractive outcomes with moderate induction of HOA and unaffected contrast sensitivity after 1 year.
Article
To evaluate the safety and complications of small-incision lenticule extraction (SMILE). Clinical control cohort study. A total of 922 healthy patients (1800 eyes) who were treated for myopia or myopic astigmatism between January 2011 and March 2013 at the Department of Ophthalmology, Aarhus, Denmark. Patients received a full preoperative examination and were treated with SMILE in both eyes and followed for 3 months (1574 eyes). Patients with complications, including loss of corrected distance visual acuity (CDVA) or dissatisfaction, were offered a late reexamination. Surgical complications and CDVA. Mean preoperative spherical equivalent refraction was -7.25±1.84 diopters (D). Average postoperative refraction was -0.28±0.52 D, and mean error of treatment was -0.15±0.50 D. By 3 months, 86% (1346 eyes) had unchanged or improved CDVA. A loss of 2 or more lines was observed in 1.5% of eyes; however, at a late follow-up visit (average, 18 months), CDVA was within 1 line of the preoperative level in all eyes. Perioperative complications included epithelial abrasions (6%), small tears at the incision (1.8%), and difficult lenticule extraction (1.9%). The cap was perforated in 4 eyes, and a major tear occurred in 1 eye; however, none of these patients had late visual symptoms. In 0.8% (14 eyes), suction was lost during surgery. Re-treatment was successful in 13 eyes, whereas 1 eye had ghost images and was re-treated with topography-guided photorefractive keratectomy (PRK). Postoperative complications included trace haze (8%), epithelial dryness on day 1 (5%), interface inflammation secondary to central abrasion (0.3%), and minor interface infiltrates (0.3%); these complications had an impact on CDVA at 3 months in only 1 case. Irregular corneal topography occurred in 1.0% of eyes, resulting in reduced 3-month CDVA (12 eyes) or ghost images (6 eyes). Topography-guided PRK was performed in 4 eyes, with improvement in 3 cases. Satisfaction was high, with only 2 patients dissatisfied at their latest visit because of blurred vision or residual astigmatism. Overall, SMILE had acceptable safety. Although 1.5% of eyes had reduced CDVA by 3 months, visual acuity was restored in the long term. Likewise, patient satisfaction was high.
Article
To study the influence of patient- and surgery-related parameters on the predictability, efficacy, and safety of small-incision lenticule extraction (SMILE) for treatment of myopia. This prospective, clinical quality, control study comprised 670 eyes from 335 patients with myopia up to -10.00 diopters (D) (spherical equivalent refraction) and astigmatism up to 2.00 D treated with SMILE in both eyes and followed for 3 months. Preoperative mean spherical equivalent refraction was -7.19±1.30 D. In eyes with emmetropia as the target refraction, 84% obtained uncorrected distance visual acuity ⩽0.10 logMAR (20/25 or better Snellen equivalent) at 3 months. Mean corrected distance visual acuity (CDVA) improved from -0.03 to -0.05 logMAR (P<.01). Two or more lines of CDVA were lost in 2.4% (16 eyes). The achieved refraction was 0.25±0.44 D less than attempted after 3 months, and 80% (537 eyes) and 94% (631 eyes) were within ±0.50 and ±1.00 D of attempted correction, respectively. Multiple linear regression analyses revealed that spherical equivalent refraction undercorrection was predicted by increasing patient age (0.10 D per decade; P<.01) and steeper corneal curvature (0.04 D per D; P<.01). Safety and efficacy of the procedure were minimally affected by age, gender, and simultaneous cylinder correction. Undercorrection of 0.25 D and small effects of patient age and corneal curvature suggest that the standard nomogram for SMILE need only minor adjustments. This study suggests that safety and efficacy are not influenced to any clinically significant degree by easily discernible patient factors.
Article
Aim: To compare 1-year results of the refractive lenticule extraction (ReLEx) flex technique performed as a commercial bilateral simultaneous procedure to a matched group of wavefront-optimized Femto-Lasik for correction of myopia and astigmatism with emphasis on contrast sensitivity and high-order aberrations (HOA). Methods: In this retrospective study 44 eyes of 22 patients with spherical equivalent (SE) of -5.13 D who underwent ReLEx were matched to 50 eyes of 25 patients with SE of -5.42 D treated by wavefront-optimized Femto-Lasik. We used Carl Zeiss Meditec (CZM) VisuMax(®) femtosecond laser system with a 200 kHz repetition rate. In addition, for Femto-LASIK, MEL 80 Excimer Laser (CZM) with aspheric ablation profiles was used for ablation. Results: At 1 year, the mean SE in the ReLEx group was -0.23 ± 0.35 D and in the Femto-LASIK group -0.15 ± 0.27 D. The mesopic contrast sensitivity of ReLEx treated eyes at 12 and 18 cpd improved from 1.49 and 0.99 to 1.54 and 1.1 respectively. In the Femto-LASIK group the numbers were pre-op 1.51 and 1.03, and after 1 year 1.54 and 1.06. The high-order aberrations (HOA) after ReLEx changed from 0.15 to 0.23 μm, and after Femto-LASIK from 0.175 to 0.320 μm (p = 0.0023). Conclusion: At 1 year, wavefront-optimized Femto-LASIK produced similar refractive outcomes to ReLEx(®) flex with better, but non-significant accuracy. In contrast, ReLEx(®) flex showed significantly less induction of HOA and better mesopic mid-term contrast sensitivity then the wavefront-optimized Femto-LASIK.
Article
To present initial clinical experience with small-incision lenticule extraction for the treatment of moderate to high myopia. Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark. Prospective clinical study. For small-incision lenticule extraction, an intrastromal lenticule was cut with a femtosecond laser and manually extracted without creation of a flap. Patients were treated and followed for 3 months. Only 1 randomly chosen eye of each patient was used in the statistical analyses. The study enrolled 144 patients. The mean preoperative spherical equivalent was -7.18 diopters (D) ± 1.57 (SD). Of eyes with emmetropia as target refraction, 40% had an uncorrected distance visual acuity of 0.1 logMAR or less 1 day after surgery; this increased to 73% at 3 months. The mean corrected distance visual acuity (CDVA) improved significantly from -0.01 (logMAR) preoperatively to -0.03 3 months postoperatively. None of the 127 eyes lost 2 lines or more of CDVA and 6 eyes lost 1 line of CDVA after 3 months. In contrast, 1 eye gained 2 lines and 24 eyes gained 1 line of CDVA. The achieved refraction was a mean of -0.09 ± 0.45 D from the attempted refraction. Of the eyes, 77% were within ±0.50 D and 95% were within ±1.00 D. Ninety-five percent of the patients would recommend the procedure to others. The refractive predictability, safety, and patient satisfaction 3 months after small-incision lenticule extraction were high and comparable to results in previous studies of femtosecond laser-assisted techniques. Drs. Hjortdal and Asp received travel reimbursement from Carl Zeiss Meditec AG, Jena, Germany. No other author has a financial or proprietary interest in any material or method mentioned.
Article
The femtosecond laser has become a rapidly and widely adopted technology for surgeons performing refractive surgery. With the advances in femtosecond lasers, clinical outcomes and safety with their use have improved. The purpose of this review is to outline the current surgical applications of the femtosecond laser in corneal refractive surgery. Many surgeons have adopted femtosecond technology for the creation of the laser in-situ keratomileusis flap secondary to its improved safety, precision and reproducibility. Other applications include astigmatic keratotomy, channel creation for the insertion of intrastromal corneal ring segments, femtosecond lenticule extraction, facilitating the insertion of corneal inlays as well as in intrastromal presbyopia correction (IntraCOR). Further novel applications continue to be developed. This review outlines the recent advances and applications of the femtosecond laser in corneal refractive surgery.
Article
To report the clinical results of small incision lenticule extraction to correct refractive errors using a femtosecond laser to refine the femtosecond lenticule extraction technique. Private laser center, Vadodara, India. Prospective clinical study. The VisuMax femtosecond laser system was used to perform small incision lenticule extraction to treat refractive errors. The laser was used to cut a refractive lenticule intrastromally to correct myopia and myopic astigmatism. The lenticule was then extracted from the stroma through a 3.0 to 5.0 mm incision. Outcome measures were corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), and manifest refraction during 6 months of follow-up. Corneal topography and ocular wavefront aberrations were also measured. The study enrolled 51 eyes of 41 patients. The mean spherical equivalent was -4.87 diopters (D) ± 2.16 (SD) preoperatively and +0.03 ± 0.30 D 6 months postoperatively. Refractive stability was achieved within 1 month (P<.01). Six months after surgery, 79% of all full-correction cases had a UDVA of 20/25 or better. The 6-month postoperative CDVA was the same as or better than the preoperative CDVA in 95% of eyes. Two eyes lost 1 line of CDVA. All-in-one femtosecond refractive correction using a small incision technique was safe, predictable, and effective in treating myopia and myopic astigmatism. No author has a financial or proprietary interest in any material or method mentioned. Additional disclosure is found in the footnotes.
Article
To compare the induced corneal wavefront aberration of eyes treated for myopia by LASIK with the SCHWIND ESIRIS laser using an aspheric aberration-neutral (Aberration-Free) ablation profile versus a classical Munnerlyn standard profile. Two consecutive groups of myopic eyes were analyzed. One group (70 eyes) was treated with a standard non-aspheric Munnerlyn profile (standard group, mean spherical equivalent refraction -4.09 +/- 1.77 diopters [D] [range: -7.75 to -0.75 D] and mean cylinder 0.78 +/- 0.76 D [range: 0.00 to 3.00 D]), and the second group (70 eyes) was treated with the ORK-CAM aspheric aberration-neutral profile (aberration-neutral group, mean spherical equivalent refraction -3.71 +/- 1.80 D [range: -8.25 to -0.75 D] and mean cylinder 1.00 +/- 0.97 D [range: 0.00 to 4.50 D]). Visual outcome, corneal wavefront data, and topographic changes after 3-month follow-up were compared. Both groups had a good visual acuity outcome with refractive predictability of +/- 0.50 D in approximately 96% of the cohort. In terms of safety, one eye in the standard group lost two lines of Snellen visual acuity. In the aberration-neutral group, no eye lost more than one line of Snellen visual acuity and 6% gained more than two lines. Corneal aberrations were measured up to the 7th order (36 Zernike terms). The induced postoperative corneal wavefront aberration at 4.0 and 6.0 mm was compared. At 6.0 mm, corneal coma increased after myopic LASIK by 0.09 microm in the standard group and by 0.07 microm in the aberration-neutral group. The induction of corneal spherical aberrations in the standard group was 0.17 microm (0.22 D) versus 0.09 microm (0.13 D) in the aberration-neutral group. The root-mean-square of induced higher order aberrations was 0.19 microm in the standard group and 0.16 microm in the aberration-neutral group. Topographies showed multifocality of 0.50 D in the standard group and 0.25 D in the aberration-neutral group. Both groups had good predictability and safety results. With the aspheric aberration-neutral profile, less corneal wavefront aberration was induced compared to eyes treated with the standard profile.