Contrast sensitivity, binocular function, and higher-order aberrations after conventional and topography-guided PRK following penetrating keratoplasty

Abstract Residual refractive error and corneal optical irregularity may impair functional vision after penetrating keratoplasty (PK). We prospectively compared functional and optical outcomes after conventional photorefractive keratectomy (C-PRK) and topography-guided PRK (TG-PRK) in 42 eyes with previous PK. Twenty eyes underwent C-PRK and 22 underwent TG-PRK. At 12 months, contrast sensitivity increased in both groups, with a greater unadjusted improvement after TG-PRK (mean change, + 0.368 vs. +0.113 log CS; P = 0.006). Total higher-order aberration root mean square increased after C-PRK (+ 0.924 μm) and decreased after TG-PRK (− 0.389 μm; P < 0.001 for the between-group difference). Changes in higher-order aberrations were not significantly correlated with changes in contrast sensitivity in either group. In multivariable analysis adjusted for baseline contrast sensitivity, spherical equivalent, and anisometropia, treatment group was not independently associated with 12-month contrast sensitivity ( P = 0.060). Both procedures were associated with improvements in visual acuity and contrast sensitivity, whereas TG-PRK was additionally associated with a reduction in higher-order aberrations. The functional benefit of TG-PRK should be interpreted cautiously because treatment allocation was non-randomized and baseline refractive characteristics differed between groups.