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Stability of the Posterior Corneal Surface After Laser Surface Ablation for Myopia

Purpose: The purpose of this study was to evaluate changes in the posterior corneal surface before and after laser surface ablation using the Pentacam. Methods: Thirty consecutive myopic eyes having laser surface ablation (14 photorefractive keratectomies, 16 laser-assisted subepithelial keratectomies) were evaluated preoperatively and postoperatively with the Pentacam. Changes in the posterior corneal curvature, posterior elevation, and anterior chamber depth were measured. Results: The 30 eyes had a mean correction of -4.50 D (range, -2.12 to -8.0) and a mean ablation depth of 58.4 μm (range, 21-106 μm). The change in mean posterior corneal curvature was -0.02 ± 0.07 mm in the central 4-mm zone (P = 0.106) and the mean posterior displacement was 0.47 ± 4.23 μm (P = 0.551). The mean change in the anterior chamber depth was -0.06 ± 0.08 mm (P < 0.001). The amount of forward shift of the posterior corneal surface had no correlation with the residual corneal thickness and ablation depth. Conclusions: There was no significant change in the posterior corneal surface after laser surface ablation.