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

PURPOSE: To assess changes in Scheimpflug-based measurements of the anterior segment after pilocarpine administration and prophylactic laser peripheral iridotomy in narrow anterior chamber angles. METHODS: 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. RESULTS: 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). CONCLUSIONS: Scheimpflug photography demonstrates significant anterior segment changes after pilocarpine and after LPI in primary angle-closure suspects.