Anterior Segment Changes After Pilocarpine and Laser Iridotomy for Primary Angle-Closure Suspects With Scheimpflug Photography

Abstract

To assess changes in Scheimpflug-based measurements of the anterior segment after pilocarpine administration and prophylactic laser peripheral iridotomy in narrow anterior chamber angles. Thirty-seven eyes in 37 patients with occludable angles were included in this prospective interventional case series. Primary angle-closure suspects (iridotrabecular contact in 3 quadrants or more) were enrolled. Patient evaluation included indentation gonioscopy, Goldmann tonometry, and optic nerve examination. The mean of 3 consecutive Pentacam measurements was taken at baseline, 45 minutes after 2% pilocarpine administration, and 1 month after laser peripheral iridotomy (LPI). Anterior chamber angle (ACA), anterior chamber volume (ACV), anterior chamber depth (ACD), pupil diameter, central corneal thickness, and intraocular pressure were measured. ACV increased significantly after LPI (from a mean ± standard error of 94.6 ± 3.6 mm(3) to 108.8 ± 3.4 mm(3), P<0.001), as did the ACA (26.7 ± 0.9 degrees to 28.2 ± 0.8 degrees, P<0.001). Central corneal thickness decreased significantly after LPI (558.1 ± 5.3 μm to 552.6 ± 5.7 μm, P=0.018). Central ACD increased slightly after LPI, but this was not statistically significant (2.13 ± 0.05 mm to 2.15 ± 0.05 mm, P=0.109). Pupil diameter and intraocular pressure also did not change significantly after LPI. After pilocarpine, the ACV decreased significantly (by 4.3 ± 1.3 mm(3), P=0.009), as did the central ACD (by 0.1 ±0.02 mm, P<0.001) and the pupil diameter (by 0.74 ± 0.06 mm, P<0.001). Scheimpflug photography demonstrates significant anterior segment changes after pilocarpine and after LPI in primary angle-closure suspects.