Anterior chamber depth measurement before and after photorefractive keratectomy - Comparison between IOL master and Orbscan II

Purpose: To measure the anterior chamber depth (ACD) with 2 different devices before and after photorefractive keratectomy (PRK). Design: Noncomparative case series. Participants: One hundred forty-three eyes of 143 patients who had undergone PRK with refractive errors ranging from -13.13 diopters (D) to +7 D (mean, -3.67 +/- 3.58) were analyzed. Methods: The ACD values preoperatively and at 1, 3, and 6 months postoperatively were measured with the Orbscan II and IOL Master. The results were analyzed using the Pearson correlation. Main Outcome Measure: Anterior chamber depth. Results: The instruments showed good agreement between the measurements before and after surgery. A significant decrease between the preoperative and 1-month postoperative measurements was found in the ACD measured from the epithelium with Orbscan II (P < 0.01) and IOL Master (P < 0.01). A nonsignificant decrease with both IOL Master (P > 0.01) and Orbscan II (P > 0.01) was found between 3 and 6 months after surgery. The ACD measured from the endothelium using the Orbscan II showed a significant difference only between the 3- and 6-month follow-up data (P < 0.01). Conclusions: The 2 devices showed good agreement, and the changes detected postoperatively seem to be related not only to corneal thinning but also to anterior segment remodeling.