Predictors of Short-Term Intraocular Pressure Change after Laser Peripheral Iridotomy: A Prospective Randomized Study.

PURPOSE: To describe short-term intraocular pressure (IOP) changes after laser peripheral iridotomy (LPI) and identify factors predicting IOP lowering. DESIGN: Multicenter, prospective randomized study. PARTICIPANTS: Four hundred fifty-five South Indian eyes of 455 participants 30 years of age or older with a diagnosis of primary angle-closure suspect (PACS), primary angle closure (PAC), or PAC glaucoma (PACG). METHODS: Participants were randomized to superior or nasal/temporal LPI. Multivariate regression models were used to determine preoperative features and LPI parameters associated with change in IOP from baseline to the 2-week postoperative examination. MAIN OUTCOME MEASURES: Change in IOP at 2 weeks after LPI compared with baseline. RESULTS: Among all treated eyes, 11.0% of eyes demonstrated a 20% or more decrease in IOP after LPI, whereas 19.6% demonstrated at least a 20% increase in IOP. Intraocular pressure changes occurring after LPI did not differ by LPI location (P > 0.5 for all comparisons). Although the anterior chamber angle widened after LPI (P < 0.001) and was classified as open after laser in most eyes (64% in all 4 quadrants), there was no significant association between gonioscopic angle opening and LPI-induced IOP change (P = 0.7). Linear regression analysis demonstrated more IOP lowering with higher baseline IOP (3.2 mmHg more lowering per 10-mmHg higher baseline IOP; 95% confidence interval [CI], 2.3-4.1 mmHg) and PAC/PACG diagnosis (1.4 mmHg more IOP lowering vs. PACS diagnosis; 95% CI, 0.2-2.6 mmHg) predicted a lower IOP after LPI. After multivariate adjustment, only higher baseline IOP predicted lower IOP after LPI (P < 0.001). Features not associated with IOP lowering included demographic, visual, and A-scan measures; baseline gonioscopic angle width; total laser energy; LPI area; and LPI location (P > 0.08 for all). Eyes with PAC/PACG, as compared with PACS, demonstrated more IOP lowering after LPI (1.2±1.7 mmHg vs. -0.4±1.0 mmHg; P < 0.001) after adjusting for baseline IOP. CONCLUSIONS: Neither LPI location nor degree of gonioscopic angle opening was associated with statistically significant change in IOP after LPI. Although significant IOP lowering after LPI was uncommon in the overall cohort, higher baseline IOP and PAC/PACG diagnosis predicted lower postoperative IOP.

Evaluation of Angle Closure as a Risk Factor for Reduced Corneal Endothelial Cell Density.

PURPOSE: Acute angle closure attacks are frequently accompanied by corneal edema. However, little is known about corneal endothelial cell status at different stages of angle closure. Here, we compared endothelial cell density (ECD) in unoperated eyes with that in eyes with open angles (OAs) and various stages of angle closure disease. MATERIALS AND METHODS: The study was conducted at Aravind Eye Hospitals in India. Masked examiners performed gonioscopy to classify each eye as follows: (1) OA, (2) primary angle closure suspect, or (3) primary angle closure (PAC)/primary angle closure glaucoma (PACG). Specular microscopy was performed and differences in ECD were analyzed using hierarchical models. RESULTS: A total of 407 patients and 814 eyes were studied, including 127 (15.6%), 466 (57.3%), and 221 (27.1%) with PAC/PACG, primary angle closure suspect, and OA, respectively. Participants were predominantly female (69.8%) and the mean age was 49.2 (SD: 8.6) years. Lower ECD was observed with increasing age [ß=-6.3 cells/mm; 95% confidence interval (CI), -9.3 to -3.3, per year; P<0.001], greater iridotrabecular contact [ß=-15.6 cells/mm; 95% CI, -28.3 to -2.9, per quadrant of contact; P=0.016), and shallow (<2.5 mm) anterior chamber depth (ß=-40 cells/mm; compared to deeper AC's (≥2.5 mm), 95% CI, 78.9-1.1; P=0.044). In age-adjusted analyses, angle closure suspects had lower ECD than OA eyes (ß=-54.7 cells/mm; 95% CI, -47.8 to -85.3; P=0.018), although PAC/PACG eyes were not significantly different from OA eyes (ß=-18.6 cells/mm; 95% CI, -85.9 to 2.5; P=0.058). CONCLUSION: In untreated eyes, only mild, clinically insignificant decrement in ECD was noted with angle closure.

Family history is a strong risk factor for prevalent angle closure in a South Indian population.

PURPOSE: To compare the prevalence of angle closure among siblings of patients with open angles (OAs), suspect angle closure (PACS), and either primary angle closure (PAC) or PAC glaucoma (PACG). DESIGN: Cross-sectional, clinical study. PARTICIPANTS: A total of 303 South Indian sibling pairs, including 81 OA probands, 143 PACS probands, and 79 PAC/PACG probands. METHODS: Probands and siblings underwent a clinical examination, including gonioscopy by a masked grader, applanation tonometry, slit-lamp biomicroscopy, optic nerve evaluation, and A-scan ultrasonography. Probands and siblings were classified into 1 of 3 groups based on the phenotype of the more severely affected eye: OA, PACS, or PAC/PACG. Multivariable regression models were used to estimate the odds of prevalent angle closure in PACS or PAC/PACG siblings compared with OA siblings. MAIN OUTCOME MEASURES: Prevalence and relative prevalence of angle closure and PAC/PACG among OA, PACS, and PAC/PACG siblings. RESULTS: Mean sibling age was 49.7 ± 8.7 years, and 56.6% of siblings were females. Angle closure was more prevalent in both PACS siblings (35.0%) and PAC/PACG siblings (36.7%) compared with OA siblings (3.7%; P < 0.001). There was PAC/PACG present in 11.4% of PAC/PACG siblings compared with 4.9% of PACS siblings (P = 0.07) and 0% of OA siblings (P = 0.002). In multivariable models adjusting for sibling age and sex, the odds of angle closure was 13.6 times greater in angle closure (PACS or PAC/PACG) siblings compared with OA siblings (95% confidence interval [CI], 4.1-45.0; P < 0.001). Sibling angle-closure risk was also greater in female (odds ratio [OR], 2.3; 95% CI, 1.3-4.0; P = 0.005) and older siblings (OR, 1.5 per 10-year increment; 95% CI, 1.1-2.0; P = 0.02). Siblings of PAC/PACG probands had a 2.3-fold greater odds (95% CI, 0.8-6.5) of having PAC/PACG compared with siblings of PACS probands, although the association was not significant (P = 0.13). CONCLUSIONS: In the South Indian population screened, siblings of angle-closure patients had a >1 in 3 risk of prevalent angle closure, whereas siblings of PAC/PACG patients had a >10% risk of prevalent PAC/PACG. Screening siblings of angle-closure patients is likely to be of high yield in finding undetected angle closure.