Anterior chamber depth measurement before and after photorefractive keratectomy. Comparison between IOLMaster and Pentacam

Abstract

Background: an accurate measurement of anterior chamber depth (ACD) both in eyes that underwent corneal refractive surgery (CRS) and in eyes that did not, can be crucial, as in case of intraocular lens (IOL) calculation in eyes that need to undergo cataract extraction, or during the evaluation of glaucomatous patients. The aim of this nonrandomized retrospective case series was to measure anterior chamber depth (ACD) before and after photorefractive keratectomy (PRK), comparing a rotating Scheimplfug camera (RSC) and a partial coherence interferometer (PCI).

Methods: 125 right eyes of 125 patients were examined. ACD was measured with RSC and a PCI preoperatively and 1, 3 and 6 months postoperatively. The results were analyzed using Friedman and ANOVA test for repeated measures, Wilcoxon test, Pearson and Bland-Altmann correlation.

Results: Both instruments showed an ACD decrease after CRS. The mean preoperative difference in ACD between the two instruments was 0.11 ± 0.11 (range: -0.07 mm to 0.73 mm) (p < 0.05) (r = 0.92). The mean difference in ACD reduction between the two instruments was: 0.08 ± 0.11 (range: -0.35 to 0.39 mm) (p < 0.05, r = 0.93) at 1 month; 0.13 ± 0.11 (range: -0.09 mm to 0.48 mm) (p < 0.05, r = 0.93) at 3 months; 0.14 ± 0.15 (range: -0.16 to 0.82 mm) (p < 0.05) (r = 0.87), at 6 months.

Conclusions: The ACD decrease shown with both instruments suggests the presence of anterior segment remodeling after PRK. RSC measurements were larger than PCI ones, both before and after PRK.

Keywords: Anterior chamber depth; PRK; Partial coherence interferometry; Refractive surgery; Rotating Scheimpflug camera.