Zonular Weakness in Patients with Primary Angle-Closure Glaucoma

Yong Yeon Kim1, Keny Kirti2, Bokun Rho1

Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea1

Department of Ophthalmology, Mumbai University, Seth G.S. Medical College, Mumbai, India2

The author has no financial interests in this study

Purpose

To evaluate the incidence of zonular weakness when primary angle-closure glaucoma patients underwent subsequent cataract surgery

Methods I Retrospective study of 91 patients

The primary angle-closure glaucoma group: 26 eyes of 26 patients with subsequent development of cataract

The control group: 65 eyes of 65 patients with no other ocular problems except for cataract

Exclusion criteria: history of ocular trauma, ectopia lentis (homocystinuria, Marfan syndrome), pseudoexfoliation

Methods II Patients in both groups underwent cataract surgery by

the phacoemulsification technique through a temporal corneal incision by the same surgeon

Zonular weakness was determined intraoperatively and confirmed postoperatively by review of video

Methods III Zonular weakness was considered to be present when multiple

sinusoidal folds formed during continuous curvlinear capsulorhexis at the tip of the capsulorhexis needle or forceps

Illustration of the formation of sinusoidal folds. Curved lines outside the lens represent loosened zonules, and straight lines outside the lens represent intact, tight zonules

Sinusoidal folds formation. When the zonule is loose, it cannot stretch the anterior capsule tightly, and the operator can find sinusoidal folds in the direction of the tip of the capsulorhexis needle or forceps

Results IParameter PACG group Control group P value

Sex

Male

Female

1

25

4

61

1.00*

Age (mean±SD, yrs) 68.46±8.59 69.98±9.29 0.83†

Axial length (mm) 22.36±0.89 22.68±0.64 0.20†

Zonular weakness

Yes

No

7

19

0

65

<0.001*

Use of tension ring

Yes

No

2

24

0

65

0.079*

IOP on presentation (mmHg) 29.53 ± 20.05 14.52 ± 2.50 <0.001†

IOP on pre-operation (mm Hg) 14.88 ± 3.97 14.07 ± 2.57 0.04†

PACG: primary angle-closure glaucomaIOP: intraocular pressure* Fisher’s exact test † T- test

Table 1. Demographic data and the patient characteristics

Results II

PAS: peripheral anterior synechiaeHx: historyCI: confidence interval* Fisher’s exact test † statistically significant

Zonular weakness P value* Odd ratio (CI)

Yes No

Glaucoma surgery Yes

No

3

4

8

11

1.00 1.03 (0.17 ~ 5.94)

Laser treatment Yes

No

6

1

10

9

0.19 5.40 (0.54 ~ 53.89)

PAS Yes 2 4 1.00 1.50 (0.20~10.82)

No 5 15

Posterior synechiae Yes 3 3 0.29 4.00 (0.57~27.81)

No 4 16

Acute attack Hx Yes 6 15 1.00 1.60 (0.14~17.41)

No 1 4

Iris atrophy Yes 5 4 0.02† 9.37 (1.29~67.64)

No 2 15

Table 2. Distribution of zonular weakness associated with other risk factors in angle-closure glaucoma patients

Discussion Increased susceptibility to zonular weakness in cases of

primary angle-closure glaucoma may be due to intraocular pressure related damage: sudden rise in intraocular pressure ischemia partial

necrosis of iris stroma and ciliary processes instability of the ciliary complex forward displacement of the lens narrowing of angle and pupillary block

Iris atrophy found after angle closure attack in our study might be an indirect sign of ischemic insult to the ciliary complex

Conclusion Zonular weakness was a significant finding in some cases

of primary angle-closure glaucoma, especially when iris atrophy was present

The weakness may be due to ischemia from raised intraocular pressure, which damages the zonules and ciliary complex, or angle-closure attack itself may develop because of pre-existing zinular weakness