Zonular Weakness in Patients with Primary Angle-Closure Glaucoma Yong Yeon Kim 1, Keny Kirti 2, Bokun Rho 1 Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea 1 Department of Ophthalmology, Mumbai University, Seth G.S. Medical College, Mumbai, India 2 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 I ParameterPACG groupControl group P value Sex Male Female * Age (mean±SD, yrs)68.46± ± † Axial length (mm) 22.36± ± † Zonular weakness Yes No <0.001 * Use of tension ring Yes No * IOP on presentation (mmHg) ± ± 2.50 <0.001 † IOP on pre-operation (mm Hg)14.88 ± ± † PACG: primary angle-closure glaucoma IOP: intraocular pressure * Fisher’s exact test † T- test Table 1. Demographic data and the patient characteristics

Results II PAS: peripheral anterior synechiae Hx: history CI: confidence interval * Fisher’s exact test † statistically significant Zonular weaknessP value * Odd ratio (CI) Yes No Glaucoma surgery Yes No (0.17 ~ 5.94) Laser treatment Yes No (0.54 ~ 53.89) PAS Yes (0.20~10.82) No515 Posterior synechiae Yes (0.57~27.81) No416 Acute attack Hx Yes (0.14~17.41) No14 Iris atrophy Yes † 9.37 (1.29~67.64) No215 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