Clinical anatomy of the anterior chamber angle in congenital aniridia and consequences for trabeculotomy/cyclophotocoagulation.

Abstract

Intraocular pressure lowering surgery in congenital aniridia glaucoma (CAG) can be complicated by dysgenesis of the limbal region, anterior chamber angle, iris, and lens. The anterior segments of 23 eyes (17 patients) with congenital aniridia were investigated under general anesthesia using ultrasound biomicroscopy (UBM). The structures of the anterior segment were examined: distance of ciliary body processes from the anterior chamber angle and positioning of Schlemm's canal. A surgical plan was created on the basis of these data. Schlemm's canal was detected in 21 of the 23 examined eyes. The mean distance from the anterior chamber angle was 1.3 ± 0.4 mm (range: 0.5-to 2.1 mm). The mean distance between the anterior chamber angle and the ciliary body was 561 ± 301 µm (range: 270-1,300 µm). The mean prominence of the ciliary body towards the lens was 799 ± 352 µm (range: 210-1,660 µm). This resulted in a precise UBM-based trabeculotomy. In addition, the ciliary body was detected and coagulated ab externo with a diode laser probe (810 nm) using diaphanoscopy and UBM. An initial UBM examination of the anterior segment is essential in eyes with CAG scheduled for trabeculotomy or cyclophotocoagulation. Clin. Anat. 31:64-67, 2018. © 2017 Wiley Periodicals, Inc.