Scleral Indentation Optimizes Visualization of Anterior Chamber Angle During Goniosynechialysis

Abstract

To propose a new surgical technique for optimized visualization of the chamber angle using scleral indentation under an operating microscope in goniosynechialysis (GSL). Six volunteers with normal chamber angle and five patients with synechial angle closure glaucoma were examined. Scleral indentation 2 mm posterior to the limbus was performed during observation of chamber angle. Width of trabecular meshwork in images was recorded through a CCD camera mounted on an operating microscope. Trabecular-iris angle and trabecular-corneal angle obtained by ultrasound biomicroscopy were used for the parameters for the angle configuration. GSL with scleral indentation was performed in the patients. According to the visibility of the chamber angle, width of trabecular meshwork in images significantly increased from 0.34 +/- 0.08 mm equivalent (mean +/- SD) to 0.67 +/- 0.14 mm equivalent (P = 0.0001) with scleral indentation. According to the angle configurations, trabecular-iris angle significantly increased from 39.6 +/- 3.8 degrees to 47.5 +/- 6.6 degrees (P = 0.0016), and trabecular-corneal angle significantly decreased from 169.8 +/- 5.5 degrees to 158.7 +/- 5.4 degrees (P < 0.0001). All patients were successfully treated with GSL using scleral indentation. Scleral indentation provided the surgeon an optimized visualization of the anterior chamber angle. Deepening of the chamber angle and steeping in trabecular-corneal curvature probably induced the plane of the trabecular meshwork less oblique to the surgeon's visual axis. This enhanced visualization promises the accuracy and safety of GSL.