Photorefractive keratectomy modification of postkeratoplasty anisometropic refractive errors.

Purpose: To evaluate the efficacy, refractive predictability and stability, and complications of photorefractive keratectomy (PRK) with adjunctive mitomycin C (MMC) in patients with postkeratoplasty anisometropia.

Methods: A retrospective review was carried out of all cases of PRK performed for postkeratoplasty anisometropia with the VISX Star S4 excimer laser with MMC between January 1, 2004, and December 31, 2008. The main outcome measures were best spectacle-corrected distance visual acuity (CDVA) and patient tolerance of full spectacle refractive correction. Secondary outcome measures were uncorrected distance visual acuity (UDVA), refractive accuracy and stability, and complications.

Results: Twenty cases met the inclusion criteria. At 6 months, the spectacle CDVA had improved from a preoperative mean of 20/50 to 20/30 (P = 0.01). Ten eyes (50%) gained 2 or more lines of CDVA. Eighteen eyes (90%) had a CDVA of 20/40 or better. All 20 patients (100%) were subjectively satisfied with full binocular spectacle correction. There was an improvement in UDVA from a preoperative mean of 20/282 to 20/52 (P < 0.001). Thirteen patients (65%) had an UDVA of 20/40 or better. There was a reduction in the mean refractive spherical equivalent from -5.2 to -0.9 diopters (D), in myopia from -7.6 to -1.8 D, and in astigmatism from 4.9 to 2.0 D. No significant change in visual acuity or refractive error occurred between 3 and 12 months. No sight-threatening complications occurred. One eye (5%) lost 2 lines of CDVA.

Conclusions: PRK with adjunctive MMC is an effective method of reducing postkeratoplasty anisometropia and providing satisfactory spectacle rehabilitation.