Peripheral laser iridoplasty opens angle in plateau iris by thinning the cross-sectional tissues
A 28-year-old Caucasian woman with a history of narrow angles in both eyes, who had bilateral laser peripheral iridotomies one year ago, presented with acute angle closure. Her presenting intraocular pressure was 26 mmHg right eye and 31 mmHg left eye. Gonioscopic exam revealed appositionally closed angles, with steeply elevated far peripheral iris configuration and double hump signs by indentation. High-frequency ultrasound biomicroscopy confirmed the anterior location of the ciliary processes with incidental findings of one iris cyst in each eye. ALPI was performed in both eyes. Postlaser intraocular pressure was reduced to 10 mmHg right eye and 12 mmHg left eye. Anterior segment SD-OCT images were taken at 3, 6, 9, and 12 o’clock of the angle of each eye before and after laser iridoplasty. The anterior segment SD-OCT demonstrated closed angles, even with patent iridotomies. Gonioscopic exam after ALPI revealed angles were open to scleral spur in the areas of iridoplasty but remained appositionally closed in the untreated areas. The anterior segment SD-OCT taken one month after ALPI detected focal iris thinning in the areas which underwent laser treatment (). Iris cross-sectional thickness was 278 μm on average in the iridoplasty-treated areas compared with 315 μm in the closed, untreated areas (). (Student’s t-test, P < 0.001).