Effect of Belin-Ambrósio deviation index on 2-year refractive outcomes of PRK.

PURPOSE: To assess the effect of preoperative Belin-Ambrósio deviation (BAD-D) index on 2-year visual, refractive, and tomographic outcomes, as well as the efficacy and safety of photorefractive keratectomy (PRK) surgery.

SETTING

Eye clinic, Mashhad, Iran.

DESIGN

Prospective cohort study.

METHODS

This study included 66 patients (66 eyes) who underwent PRK surgery, with a minimum follow-up period of 2 years. Participants were divided into 2 groups: preoperative BAD-D ≥1.60 (high BAD-D) and preoperative BAD-D <1.60 (low BAD-D). Preoperative and postoperative visual, refractive, and tomographic parameters were evaluated, and the efficacy and safety of the procedure were compared between groups.

RESULTS

66 patients with a mean age of 35.50 ± 8.21 years (range 22 to 55 years) were included. Postoperatively, the mean spherical equivalent (SE) of refractive error was +0.32 ± 0.65 diopters (D) in the high BAD-D group and +0.18 ± 0.66 D in the low BAD-D group ( P = .40). In addition, at 2 years of follow-up, the mean uncorrected distance visual acuity was 0.98 ± 0.07 in the high BAD-D group and 0.97 ± 0.08 in the low BAD-D group ( P = .905). Among the postoperative tomographic parameters, front elevation thickness, maximum Ambrósio relational thickness, astigmatism, and central corneal thickness were significantly different between the 2 groups (all, P < .05). At the 2-year follow-up, the mean Safety Index was 1.02 ± 0.04, and 1.01 ± 0.04 in high and low BAD-D groups, respectively ( P = .37), and the mean Efficacy Index was 0.99 ± 0.07 and 0.98 ± 0.06 in high and low BAD-D groups, respectively ( P = .40).

CONCLUSIONS

The preoperative BAD-D index does not predict postoperative visual, refractive, and tomographic outcomes in patients with low-to-moderate myopia. However, in patients with normal preoperative BAD-D values, higher agreement was expected between the attempted and achieved SE.