Quantitative evaluation of anterior chamber changes after iridotomy using Pentacam anterior segment analyzer

Abstract

Purpose: To evaluate changes in anterior chamber morphology with the Pentacam anterior segment analyzer and gonioscopy after laser peripheral iridotomy (LPI) in patients with primary angle closure glaucoma and narrow angle and to compare central corneal thickness measurements performed with Pentacam and ultrasound pachymetry.

Methods: Twenty eyes of 20 patients were enrolled in this prospective interventional study. Before and after LPI, volume, angle, and central and peripheral depth of anterior chamber was quantified with Pentacam. Central corneal thickness was measured with Pentacam and ultrasound pachymetry.

Results: Mean central corneal thickness as measured with Pentacam pachymetry was slightly lower than the measurements provided by ultrasonic pachymetry (551.9 microm, range 509-659, versus 556.8 microm, range 520-644) (p=0.93) with an intraclass correlation coefficient of 0.92. Anterior chamber angle increased from 20.32 (standard deviation [SD] 4.2) to 22.31 degrees (SD 3.9). Anterior chamber central depth increased significantly from 1.79 mm (SD 0.22) to 1.85 mm (SD 0.21) and volume changed from 72.18 mm (SD 16.82) to 89.12 mm (SD 12.3), p=0.001. Gonioscopy showed that Shaffer angle widened significantly in all quadrants. Mean intraocular pressure changed from 20.8 mmHg to 18.3 mmHg after LPI (p<0.05).

Conclusions: In patients with primary angle closure glaucoma and narrow angles, anterior chamber volume, angle, and central and peripheral depth, measured with Pentacam, increase significantly after LPI.