Quantitative Analysis of Anterior Chamber following Peripheral Laser Iridotomy using Pentacam in Eyes with Primary Angle Closure

Abstract

Purpose.

To quantify the effects of laser peripheral iridotomy (LPI) on peripheral anterior chamber depth (PACD), central internal anterior chamber depth (CACD), and anterior chamber volume (ACV) using Rotating Scheimpflug Imaging System, i.e., Pentacam, on Asian Indian eyes.

Methods.

This was an institutional, prospective, nonrandomized, interventional study. Sixty-eight eyes of 68 consecutive patients with primary angle closure were enrolled. Pentacam scanned the anterior ocular segment with the 25-image acquisition scan protocol and PACD, CACD, and ACV values were obtained. The PACD was measured in nasal, temporal, superior, and inferior meridian at 4 mm and 8 mm circles. Nd:YAG laser iridotomy was performed. Preiridotomy, immediate postiridotomy, 1 week and 1 month postiridotomy data for PACD, CACD, and ACV were acquired. The t test and repeated-measures analysis of variance (ANOVA) and one-way ANOVA were used for statistical significance.

Results.

Pre-LPI ACV increased immediately after iridotomy (28.4 mm³; p≤0.001), at 1 week (15.9 mm³; p≤0.001), and at 1 month post-LPI (19.8 mm³; p=0.00). There was no change in CACD (p>0.05). Significant PACD deepening was observed at 4 mm and 8 mm in all meridians (p<0.001) at all visits.

Conclusions.

Laser peripheral iridotomy significantly increased the PACD and ACV. Extent of the LPI-induced PACD increase was enhanced with increasing distance from the optical axis.