Laser iridotomy tied to sustained angle widening in eyes

Laser peripheral iridotomy (LPI) brings sustained angle widening to about two-thirds of patients with persistent angle closure, reports a study.

A total of 480 patients were included in this study, of whom 375 with phakia completed the 5-year follow-up, and 130 had complete imaging. All participants underwent LPI in one randomly selected eye. The authors then assessed the proportion of eyes with persistent gonioscopic angle closure (≥2 quadrants), its predictors, and the changes in biometric parameters.

Persistent gonioscopic angle closure occurred in 124 eyes (33.1 percent) treated with LPI among 375 participants with 5-year follow-up. LPI led to significant reductions in the risk of persistent gonioscopic angle closure at 5 years (odds ratio [OR], 0.12, 95 percent confidence interval [CI], 0.09‒0.17; p<0.001).

Among patients with complete imaging, 34 eyes (26.2 percent) showed persistent gonioscopic angle closure, and this proportion did not differ significantly from that of the entire cohort (p=0.17).

Greater iris thickness at 750 μm from the scleral spur (IT750) at baseline (per 0.1 mm; OR, 1.71, 95 percent CI, 1.21–2.57; p=0.004) and younger age at baseline (per 10 years; OR, 0.30, 95 percent CI, 0.13–0.61; p=0.002) predicted persistent angle closure, while lower mean gonioscopic grade was borderline predictive (OR, 0.35, 95 percent CI, 0.12‒1.00; p=0.050).

Further analysis revealed that greater IT750 significantly correlated with persistent angle closure only in eyes with baseline angle opening distance at 500 μm from the scleral spur below the median (p=0.005). Moreover, angle width (p<0.001 for all) increased within 2 years after LPI and remained stable thereafter.

“A thicker iris at baseline in eyes with a narrower angle was predictive of persistent angle closure despite treatment,” the authors said.