Visual Outcomes and Aberrometric Changes With Topography-Guided Photorefractive Keratectomy Treatment of Irregular Astigmatism After Penetrating Keratoplasty

Purpose: To evaluate the visual acuity and keratometric and aberrometric changes in patients with corneal transplants (PKP), who underwent topography-guided photorefractive keratectomy (TG-PRK) with mitomycin C (MMC). Methods: In this case study, 15 patients with spherical equivalents ranging from -11.00 to -0.25 diopters (D) who underwent penetrating corneal transplantation and had irregular astigmatism ranging from 27.5 to 22.0 D underwent TG-PRK with MMC. Corneal topography and wavefront of all patients were measured preoperatively and 12 months postoperatively. Results: Twelve months after TG-PRK with MMC, 46% of eyes achieved a best spectacle-corrected visual acuity (BSCVA) of 20/20 compared with 1 eye preoperatively (P = 0.0221, x(2) test). The BSCVA did not improve in 1 patient and increased by 1 line or more in all others. Astigmatism decreased significantly (P = 0.003) from 5.10 +/- 0.4 D to 3.37 +/- 0.06 D, the corneal best-fit sphere increased and keratometry measurements flattened significantly (P = 0.0001 for both comparisons), and the corneal total root mean square aberrations and trefoil decreased significantly (P = 0.0077 and P = 0.0054, respectively) from 9.11 +/- 2.56 mm to 7.58 +/- 3.15 mm and 2.00 +/- 1.2 to 1.38 +/- 0.27 mu m, respectively, as measured by wavefront aberrometry. Conclusions: Twelve months postoperatively, the BSCVA improved significantly, the lines of vision increased, and astigma-tism, corneal best-fit sphere, mean keratometry, corneal thickness, corneal root mean square total, and corneal spherical aberrations decreased. TG-PRK with MMC is a good alternative for correcting post-PKP cases with irregular astigmatism with elevated higherorder aberrations.