Long-term Persistent Angle Closure and Anatomic Changes after Laser Iridotomy in Suspected Primary Angle-Closure

초록

Purpose: To evaluate the proportion of patients with, and anatomic predictors of, persistent angle closure 5 years after laser peripheral iridotomy (LPI) in primary angle-closure suspect and to assess anterior segment (AS) anatomic changes over the 5-year follow-up. Design: Subanalysis of randomized controlled trial (the Singapore Asymptomatic Narrow Angles Laser Iridotomy Study). Participants: Of the 480 patients, 375 patients with phakia completed the 5-year follow-up, and 130 patients had complete imaging. Methods: All patients underwent LPI in 1 randomly selected eye. The proportion of eyes with persistent gonioscopic angle closure (>= 2 quadrants), its predictors, and the changes in biometric parameters were evaluated. Main Outcome Measures: Odds ratio (OR; with 95% confidence interval [CI]) for predictors. Results: Among 375 participants with 5 years of follow-up, persistent gonioscopic angle closure occurred in 124 LPI-treated eyes (33.1%). At 5 years, LPI significantly reduced the risk of persistent gonioscopic angle closure (OR, 0.12 [95% CI, 0.09-0.17]; P < 0.001). In the imaging cohort (n = 130), 34 eyes (26.2%) had persistent gonioscopic angle closure, a proportion not significantly different from that of the entire cohort (P = 0.17). In multivariable analysis, greater iris thickness measured at 750 mu m from the scleral spur (IT750) at baseline (per 0.1 mm; OR, 1.71 [95% CI, 1.21-2.57]; P = 0.004) and younger age at baseline (per 10 years; OR, 0.30 [95% CI, 0.13-0.61]; P = 0.002) were associated with persistent angle closure, whereas lower mean gonioscopic grade was borderline significant (per grade, OR, 0.35 [95% CI, 0.12-1.00]; P = 0.050). Additional analysis showed that greater IT750 was associated significantly with persistent angle closure only in eyes with baseline angle opening distance at 500 mu m from the scleral spur below the median (P = 0.005). Angle width (P < 0.001 for all) increased within 2 years after LPI and remained stable thereafter. Conclusions: In approximately two-thirds of patients, LPI induces sustained angle widening. A thicker iris at baseline in eyes with a narrower angle was predictive of persistent angle closure despite treatment.

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