Anterior chamber configuration changes after cataract surgery in eyes with glaucoma.

Abstract

To evaluate changes in anterior chamber depth (ACD) and angle width induced by phacoemulsification and intraocular lens (IOL) implantation in eyes with glaucoma, using anterior segment optical coherence tomography (AS-OCT).
Eleven eyes of 11 patients with angle-closure glaucoma (ACG) and 12 eyes of 12 patients with open-angle glaucoma (OAG) underwent phacoemulsification and IOL implantation. Using AS-OCT, ACD and angle parameters were measured before and 2 days after surgery. Change in intraocular pressure (IOP) and number of ocular hypotensive drugs were evaluated.
After surgery, central ACD and angle parameters increased significantly in eyes with glaucoma (p < 0.05). Prior to surgery, mean central ACD in the ACG group was approximately 1.0 mm smaller than that in the OAG group (p < 0.001). Post surgery, mean ACD of the ACG group was still significantly smaller than that of the OAG group. No significant differences were found in angle parameters between the ACG and OAG groups. In the ACG group, postoperative IOP at the final visit was significantly lower than preoperative IOP (p = 0.018) and there was no significant change in the number of ocular hypotensive medications used, although clinically, patients required fewer medications. In the OAG group, the IOP and number of ocular hypotensive drugs were almost unchanged after surgery.
The ACD and angle width in eyes with glaucoma increased significantly after phacoemulsification and IOL implantation. Postoperative ACD significantly differed between the ACG and OAG groups, whereas angle parameters did not differ.

Full text

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Original Article
Anterior Chamber Configuration Changes after Cataract Surgery
in Eyes with Glaucoma

Martha Kim1, Ki Ho Park2, Tae-Woo Kim1, Dong Myung Kim2
1Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Korea
2Department of Ophthalmology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
pISSN: 1011-8942 eISSN: 2092-9382
Korean J Ophthalmol 2012;26(2):97-103
http://dx.doi.org/10.3341/kjo.2012.26.2.97
Angle-closure glaucoma (ACG) and open-angle glau-
coma (OAG) are thought to arise from different pathogen-
eses. ACG typically results from abnormal anatomy of
the anterior segment of the eye, such as a narrow anterior
chamber angle, a shallow anterior chamber depth, a thicker
lens, a more anterior lens position, a small corneal diam-
eter or a shorter axial length [1-4]. Lens position and size
play a pivotal role in angle closure; therefore, lens extrac-
tion is a novel, efficient treatment protocol of acute and
chronic ACG [5-9]. On the other hand, those with OAG ap-
pear to have a normal iridocorneal angle but the aqueous
outflow is low. To better understand the pathophysiology
of glaucoma and to apply such knowledge to clinical treat-
ment, precise visualization and quantitative evaluation of
angle configurations is essential.
Recently, anterior segment optical coherence tomogra-
phy (AS-OCT) has been used for quantitative evaluation of
anterior segment configurations. A number of studies that
used AS-OCT have reported adequate angle configuration
change after cataract extraction in normal eyes [10-12].
In this study, we compared changes in anterior chamber
configurations in ACG- and OAG-eyes after phacoemulsi-
fication and posterior chamber intraocular lens (IOL) im-
© 2012 The Korean Ophthalmological Society
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses
/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received: September 28, 2010 Accepted: March 7, 2011
Corresponding Author: Ki Ho Park, MD. Department of Ophthalmology,
Seoul National University College of Medicine, #101 Daehak-ro, Jongno-
gu, Seoul 100-799, Korea. Tel: 82-2-2072-2438, Fax: 82-2-741-3187,
E-mail: kihopark@snu.ac.kr
Purpose: To evaluate changes in anterior chamber depth (ACD) and angle width induced by phacoemulsifica-
tion and intraocular lens (IOL) implantation in eyes with glaucoma, using anterior segment optical coherence
tomography (AS-OCT).
Methods: Eleven eyes of 11 patients with angle-closure glaucoma (ACG) and 12 eyes of 12 patients with open-
angle glaucoma (OAG) underwent phacoemulsification and IOL implantation. Using AS-OCT, ACD and angle
parameters were measured before and 2 days after surgery. Change in intraocular pressure (IOP) and num-
ber of ocular hypotensive drugs were evaluated.
Results: After surgery, central ACD and angle parameters increased significantly in eyes with glaucoma (p <
0.05). Prior to surgery, mean central ACD in the ACG group was approximately 1.0 mm smaller than that in
the OAG group (p < 0.001). Post surgery, mean ACD of the ACG group was still significantly smaller than that
of the OAG group. No significant differences were found in angle parameters between the ACG and OAG
groups. In the ACG group, postoperative IOP at the final visit was significantly lower than preoperative IOP (p
= 0.018) and there was no significant change in the number of ocular hypotensive medications used, although
clinically, patients required fewer medications. In the OAG group, the IOP and number of ocular hypotensive
drugs were almost unchanged after surgery.
Conclusions: The ACD and angle width in eyes with glaucoma increased significantly after phacoemulsification
and IOL implantation. Postoperative ACD significantly differed between the ACG and OAG groups, whereas
angle parameters did not differ.
Key Words: Angle-closure glaucoma, Anterior chamber, Anterior eye segment, Cataract extraction,
Open-angle glaucoma

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Korean J Ophthalmol Vol.26, No.2, 2012
plantation. For a quantitative analysis of the anterior cham-
ber configurations, we used AS-OCT. We also evaluated
the influence of cataract surgery in controlling intraocular
pressure (IOP) and the number of required ocular hypoten-
sive medications in patients with ACG and OAG both pre-
and post-surgery.
Materials and Methods
Twenty-three eyes of 23 patients participated in this
study (11 eyes affected by ACG and 12 eyes affected by
OAG). A total of 23 eyes underwent phacoemulsification
and foldable IOL implantation from March 2008 to July
2009. Informed consent was obtained from all patients in
compliance with the World Medical Association Declara-
tion of Helsinki. The local institutional review board ap-
proved the protocol.
All patients completed an ophthalmologic examination
including best-corrected visual acuity and manifest re-
fraction, slit-lamp biomicroscopy, Goldmann applanation
tonometry, gonioscopy, and indirect ophthalmoscopy. The
number of ocular hypotensive medications being taken by
each patient was assessed prior to surgery.
Axial lengths were obtained using the Humphrey 820
model A-scan ultrasound unit (Humphrey Systems, Dub-
lin, CA, USA). ACG and OAG patients were categorized
based on recent diagnostic classifications of glaucoma
[13]. In brief, ACG is defined as an eye with an occlud-
able drainage angle and features indicating that trabecular
obstruction by the peripheral iris has occurred, such as
peripheral anterior synechia, elevated IOP, iris whirl-
ing, ‘glaucomfleken’ lens opacities or excessive pigment
deposition on the trabecular surface, accompanied with
glaucomatous optic disc changes. Eyes with a history of
angle-closure attack and/or previous laser iridotomy were
also included in the ACG group. The OAG was defined as
an eye with an open angle, elevated IOP and glaucomatous
optic neuropathy such as optic nerve head excavation or
thinning of the neuroretinal rim and corresponding visual
field defects.
One surgeon (PKH) performed all operations under
topical anesthesia. In all but two eyes, a 2.75 mm clear
corneal incision through a temporal approach was created;
in two eyes, a 2.2 mm clear corneal incision was made.
Through this incision, the continuous curvilinear capsulor-
rhexis measuring approximately 5.5 mm in the diameter
was formed. The hydrodissection was followed by phaco-
emulsification of the nucleus and cortex aspiration. The
lens capsule was inflated with an ophthalmic viscosurgical
device (OVD) and the foldable IOL was placed in the cap-
sular bag. The corneal wound was not sutured. There were
no intraoperative or postoperative complications for any
patients.
We performed AS-OCT (Visante; Carl Zeiss Meditec,
Dublin, CA, USA) on the eyes of both patient groups
before surgery and 2 days after. One examiner obtained
all images under identical lighting conditions. For the
measurement, the pupil was undilated and the patient was
asked to sit and fixate on an indicator in the AS-OCT. Im-
ages of the nasal and temporal angle quadrants (0° and
180° meridians) were captured until the centration and
quality were enough to analyze (Fig. 1). IOP measurement
using a Goldmann applanation tonometer and an assess-
ment of the number of ocular hypotensive medications
were performed every visit after surgery.
We selected the best images and analyzed them using
custom software (Iridocorneal module, Carl Zeiss Med-
itec). Central anterior chamber depth (ACD), defined as the
distance from the endothelium at the center of the cornea
to the anterior pole of the lens or IOL, was an important
parameter in the analysis. We calculated anterior chamber
angle width in two ways: 1) anterior chamber angle (ACA)
- the angle between the iris tangential line and that of the
posterior corneal surface with its apex in the angle recess
and 2) trabecular-iris angle (TIA) - the angle between the
arms passing through a point on the trabecular meshwork
500 μm from the scleral spur and the point perpendicu-
larly opposite on the iris. Anterior chamber angle width
was also analyzed using standardized angle parameters
after manual identification of the scleral spur: 1) angle-
opening distance at 500 μm (AOD500) and AOD at 750 μm
(AOD750) – distance of a perpendicular from the trabecular
meshwork on the iris at a point 500 or 750 μm from the
sclera spur and 2) trabecular-iris space area up to 500 μm
Fig. 1. Anterior segment optical coherence tomography showed
changes in the anterior chamber configuration induced by phaco-
emulsification and posterior chamber intraocular lens implanta-
tion in eyes with angle-closure glaucoma (ACG) and open-angle
glaucoma (OAG). Preoperatively, the anterior chamber depth and
angle width in eyes with ACG (left) were smaller than in the eyes
with OAG (right). However, the anterior chamber depth and angle
width were almost identical in eyes with ACG and OAG after
cataract surgery.
Angle-closure glaucoma
Preoperative
Postoperative
Open-angle glaucoma

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M Kim, et al. AC Change after Cataract Surgery in Glaucoma
(TISA500) or 750 μm (TISA750) – the area bounded by the
corneal endothelium, trabecular meshwork and anterior
iris surface out to a distance of 500 or 750 μm from the
scleral spur.
All statistical analyses were performed using a chi-
Square test, Mann-Whitney U-test or Wilcoxon’s rank sum
test. Age and axial length were adjusted for using the gen-
eral linear model. All results were considered significant at
p < 0.05, two-tailed.
Results
The mean age of patients was 69.4 ± 6.6 years. The mean
follow-up period was 3.82 ± 4.51 months (range, 1 to 16
months) in the ACG group and 5.33 ± 2.93 months (range,
1 to 9 months) in the OAG group. Patient characteristics
are listed in Tables 1 and 2. Three types of IOLs were used.
No significant differences were found between the two
groups with regard to age, gender, laterality, visual acuity,
Table 2. Comparison of baseline characteristics between patients with open-angle glaucoma and angle-closure glaucoma
ACG group (n = 11)
69.5 ± 5.8
2 : 9
6 : 5
-2.6 ± 3.2
22.4 ± 0.9
-0.7 ± 0.4
16.9 ± 7.1
3.8 ± 4.5
OAG group (n = 12)
69.3 ± 7.5
8 : 4
6 : 6
0.1 ± 2.1
23.6 ± 1.1
-0.6 ± 0.6
13.3 ± 3.4
5.3 ± 1.9
p-value
0.880*
0.532†
0.835†
0.113*
0.013*
0.449*
0.091*
0.104*
Age (year ± mean deviation)
Gender (M : F)
Laterality (R : L)
Refractive error (diopters)
Axial length (mm)
Visual acuity (logMAR)
Intraocular pressure (mmHg)
Follow-up periods (mon)











ACG = angle-closure glaucoma; OAG = open-angle glaucoma; logMAR = logarithm of the minimal angle of resolution.
*Mann-Whitney U-test; †Chi-square test.
Table 1. Characteristics of patients
Patients
no.
Sex Age Laterality Diagnosis
Previous
treatment
Preoperative
IOP
Postoperative
IOP
No. of
preoperative
medications
1
0
5
2
0
4
4
0
1
1
0
1
1
3
4
3
2
2
2
2
1
4
3
No. of
postoperative
medications
1
0
2
2
0
3
0
0
1
0
0
1
1
2
4
5
1
0
2
2
1
4
3
Systemic
disease
Implanted
IOL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
F
F
F
F
M
M
F
F
F
F
F
M
M
M
F
M
F
M
F
M
M
F
M
61
75
65
68
70
69
77
73
70
77
60
68
53
72
70
68
73
74
57
80
71
74
72
R
L
R
R
R
R
R
L
L
L
L
R
L
R
L
L
R
R
L
L
L
R
R
ACG
ACG
ACG
ACG
ACG
ACG
ACG
ACG
ACG
ACG
ACG
OAG
OAG
OAG
OAG
OAG
OAG
OAG
OAG
OAG
OAG
OAG
OAG
LI
LI
LI
LI
LI
TLE
LI
LI
LI
LI
LI
16
14
19
14
9
14
37
14
15
17
18
10
20
13
14
14
17
6
12
12
15
14
16
15
12
18
14
9
11
12
10
8
12
15
11
16
13
18
17
11
8
16
10
12
17
12
DM, HTN
HTN
DM, HTN
HTN
B
IQ
B
S
IQ
IQ
S
IQ
IQ
IQ
IQ
IQ
B
IQ
B
IQ
IQ
IQ
IQ
B
IQ
IQ
IQ
DM, HTN
HTN
HTN
DM, HTN
TLE DM
HTN
TLE
DM, HTN
HTN
IOP = intraocular pressure; IOL = intraocular lens; ACG = angle-closure glaucoma; LI = laser iridotomy; DM = diabetes mellitus; HTN =
hypertension; TLE = trabeculectomy; OAG = open-angle glaucoma; B = Biovue IOL (Oii, Ontario, CA, USA); IQ = Acrysof IQ IOL (Alcon,
Fort Worth, TX, USA); S = Acrysof SA60AT IOL (Alcon).

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Korean J Ophthalmol Vol.26, No.2, 2012
refractive errors, follow-up periods and preoperative IOP.
Axial length was significantly longer in eyes with OAG
than with ACG (p = 0.013).
Table 3 shows the anterior chamber parameters before
and after cataract surgery, and percentage change for each
parameter after surgery of the two groups. Preoperative
mean ACD of the ACG group was significantly less than
that of the OAG group (p < 0.001). After surgery, ACD in-
creased significantly after cataract surgery in both groups
(p < 0.01) and the difference was greater in the ACG
group (p < 0.001). The differences in ACD, between the
two groups remained statistically significant after surgery,
and postoperative ACD was smaller in the ACG group (p
< 0.01). However, postoperative ACD did not remain sig-
nificant after adjusting for age and axial length (p = 0.85),
whereas preoperative ACD and changes in ACD remained
significant (p < 0.001 and p = 0.002, respectively).
The ACA in the nasal and temporal quadrants in both
the ACG and OAG groups increased significantly after
surgery (p < 0.05). The ACA of the ACG group was signif-
icantly smaller than that of the OAG group before surgery.
Postoperative ACA and the differences associated with the
surgery, did not statistically differ between groups. After
adjusting for age and axial length, preoperative ACA of
both angles did not significantly differ between groups (p
= 0.062 and p = 0.077, respectively). Other angle param-
eters that used the scleral spur as a reference point showed
similar results. All angle parameters in the ACG and OAG
patients increased significantly after the surgery (p < 0.01)
(Table 3). Each of the angle parameters showed no signifi-
cant differences between the ACG and OAG groups before
and after surgery, except for preoperative AOD750 in the
temporal quadrant (p = 0.037). After adjusting for age and
axial length, all angle parameter changes did not signifi-
cantly differ by group. Finally, there were no significant
differences on any parameters in the nasal and temporal
quadrants after surgery.
Preoperative and postoperative IOP and the number of
ocular hypotensive medications needed to maintain a stable
IOP were also assessed. In the ACG group, preoperative
IOP was 17.00 ± 7.14 mmHg and postoperative IOP at two
days after surgery decreased to 14.09 ± 4.81 mmHg. The
IOP at one month postoperatively and the IOP at the final
visit were 12.36 ± 2.94 mmHg and 12.18 ± 4.38 mmHg,
respectively, which were significantly decreased compared
to the preoperative IOP (p = 0.014 and p = 0.018, respec-
tively). The IOP in the OAG group increased from 13.33 ±
3.37 mmHg to 15.00 ± 7.62 mmHg from pre-surgery to im-
mediately post-surgery. However, the IOP after one month
and the final IOP were 13.42 ± 3.26 mmHg and 13.42 ± 3.23
mmHg in OAG group, which were almost identical to the
mean value prior to surgery (Fig. 2A). The number of ocu-
lar hypotensive medications needed decreased from 1.64
± 1.86 to 0.82 ± 1.08, one month after surgery in the ACG
group and was maintained at the final visit. The number of
medications needed in the OAG group was 2.33 ± 1.07 pre-
operatively and 2.17 ± 1.53 at one month postoperatively,
which was maintained at the final visit (Fig. 2B). These
differences were not statistically significant.
Discussion
In this study, we analyzed the change in anterior seg-
ment configuration after cataract extraction and posterior
Table 3. Anterior chamber depth and angle parameters before and after cataract surgery in eyes with glaucoma
ACG OAG
PreoperativePostoperative % of
increase
124
116
93
123
99
131
118
103
103
114
106
88
64
p-valuePreoperative Postoperative% of
increase
50
47
47
85
55
84
55
90
57
87
57
55
38
p-value
ACD*
ACA*
1.63 ± 0.23
14.06 ± 4.33

30.40 ± 5.78
29.68 ± 9.92
3.65 ± 0.190.004
0.003 22.75 ± 8.14
0.008 24.16 ± 7.73
0.006 333.00 ± 205.38 616.92 ± 215.26
0.004 400.92 ± 218.30 620.58 ± 198.16
0.003 469.50 ± 249.78 863.83 ± 222.88
0.003 554.25 ± 270.02 861.08 ± 262.16
0.008 117.58 ± 68.81
0.004 148.92 ± 76.66
0.006 217.17 ± 123.77 405.08 ± 123.87
0.004 267.42 ± 132.02 420.08 ± 122.65
0.006 30.99 ± 15.27
0.004 36.03 ± 14.31
2.62 ± 0.47
33.52 ± 4.31
35.61 ± 4.78
3.93 ± 0.26 0.001
0.001
0.065
0.012
0.012
0.001
0.001
0.012
0.012
0.012
0.012
0.012
0.012
Nasal
Temporal 15.40 ± 4.92
* (µm) Nasal
Temporal 249.09 ± 84.40 496.82 ± 190.24
AOD750
326.27 ± 154.16 754.18 ± 136.95
Temporal 327.00 ± 97.95 711.36 ± 230.52
TISA500
87.09 ± 43.84 176.45 ± 57.84
Temporal 88.82 ± 26.93 180.27 ± 72.30
TISA750
155.63 ± 77.12 333.00 ± 88.28
Temporal 159.82 ± 46.19 329.09 ± 122.29
TIA*
Nasal 23.78 ± 10.51 44.62 ± 8.36
Temporal 25.82 ± 7.57
AOD500
233.27 ± 120.76 520.91 ± 157.12
* (µm) Nasal
* (µm2) Nasal 223.00 ± 72.68
233.92 ± 67.85
* (µm2) Nasal
48.17 ± 8.15
49.79 ± 9.32 42.46 ± 11.98
ACG = angle-closure glaucoma; OAG = open-angle glaucoma; ACD = anterior chamber depth; ACA = anterior chamber angle; AOD =
angle opening distance; TISA = trabecular-iris space area; TIA = trabecular-iris angle.
*Wilcoxon signed ranks test.

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M Kim, et al. AC Change after Cataract Surgery in Glaucoma
chamber IOL implantation in eyes with ACG and OAG
using anterior segment OCT to quantitatively measure
parameters. Our results showed that the ACD and ACA
parameters significantly differed from pre- to post-surgery,
which is consistent with findings from previous studies
[5,10-12,14]. Compared to the OAG group, the ACG group
had a smaller ACD before and after surgery. Preoperative
ACD was 1.63 ± 0.23 mm in the ACG group and 2.62 ± 0.47
mm in the OAG group. Differences in ACD between the
two groups were also consistent with findings of an earlier
study [5].
The differences in the changes of the ACA between the
ACG and OAG groups were 8.69˚ at the nasal and 8.76˚ at
the temporal (mean 8.73˚) quadrants before cataract sur-
gery, and 3.12˚ at the nasal and 5.93˚ at the temporal (mean
4.53˚) quadrants after surgery. Preoperative ACA was sig-
nificantly smaller in the ACG group compared to the OAG
group, whereas postoperative ACA did not differ between
the two groups. Additionally, the change caused by cata-
ract extraction did not significantly differ between the two
groups. This result suggests that the lens factor may be an
important pathological parameter in ACG. Although there
are likely other factors that are also important. However,
after adjusting for age and axial length, other parameters
did not significantly differ between groups except for pre-
operative ACD and changes in ACD, suggesting that axial
length may also be an important factor which influence to
the anterior chamber configuration.
All angle parameters including the AOD, TISA and TIA
significantly increased after surgery in both groups (p
< 0.01). Percent change on these parameters was always
smaller in the OAG versus ACG group. In the OAG group,
the AOD and TISA increased by about 85% at the nasal
quadrant and by 55% at the temporal quadrant. This result
was consistent with the findings of a previous study [10].
Nolan et al. [10] studied 21 normal subjects using the AS-
OCT before and after cataract extraction surgery. After
the surgery, the AOD500 and TISA750 increased by about
80% at the nasal quadrant and about 55% at the temporal
quadrant. Collectively, these results suggest that individu-
als with OAG likely have similar angle anatomy compared
to normal subjects and that the effect of cataract surgery
on angle anatomy was similar to that done in normal eyes
[12]. In contrast, the AOD and TISA in the ACG group
increased 112% (from 99% to 131%) after cataract surgery
and showed no differences by quadrant in the present
study. The percent increase did differ by quadrant in the
OAG group, whereas it was identical in the ACG group.
These differences may have been due to the small number
of patients in the present study; however, other factors
could have influenced these results. One other possible
explanation is that the goniosynechiolysis of the angle,
during surgery, in conjunction with the OVD and fluids
via the temporal clear cornea, might have had differential
quadrant effects.
In the ACG group, the IOP was reduced by 17% (2.91
mmHg) after surgery, whereas the IOP increased by 13%
(1.67 mmHg) in the OAG group immediately postopera-
tively. There were two patients that had peak IOP in the
OAG group and one of them was a steroid responder. The
final IOP measured at the final visit decreased by 27% (4.64
mmHg) in ACG group and there were no changes in the
OAG group. The final IOP was similar in the two study
groups; however, the percent change was significantly dif-
ferent (p < 0.05). Furthermore, the change in the number
of ocular hypotensive medications needed differed in the
two groups (50% reduction in ACG group vs. 7% reduc-
tion in OAG group). Collectively, these results indicate that
cataract surgery might cause more changes in terms of
lowering the IOP and reducing the number of medications
needed for treatment in those with ACG than those with
OAG.
ACGOAG
No.of medication
0
1
2
3
Preoperative
Postoperative
20
10
0
ACG
*
OAG
IOP (mmHg)
Preoperative
Immediate postoperative
Final postoperative
AB
Fig. 2. Change in mean intraocular pressure (IOP) and the number of ocular hypotensive medications needed in the two groups,
preoperatively and postoperatively. (A) For the angle-closure glaucoma (ACG) group, the IOP showed a tendency to decrease during
the immediate postoperative period and the final IOP was significantly decreased compared to the preoperative IOP (*p < 0.05). In
contrast, the IOP for the open-angle glaucoma (OAG) group showed no significant difference after cataract surgery. (B) The number of
hypotensive medications was also decreased after surgery in the ACG group whereas it was almost identical in the OAG group.