Ocular optical aberrations after photorefractive keratectomy for myopia and myopic astigmatism

Objectives: To study the effects of photorefractive keratectomy on ocular o ptical aberrations and to establish correlations with glare vision and low- contrast vision. Methods: Preoperative ocular aberroscopy of 15 eyes undergoing photorefract ive keratectomy was compared with aberroscopy at 3 months postoperatively b y means of a newly developed automated aberroscope of the Tschern-ing type. The correlation of the wavefront errors with best spectacle-corrected visu al acuity, low-contrast visual acuity, and visual acuity under glare condit ions was analyzed. Results: In any individual treated, the total wavefront error increased. On average, the total wavefront error increased by a factor of 17.65; this in crease was highly statistically significant (P=.001). Also, the correlation with best-corrected visual acuity, low-contrast visual acuity, and glare v isual acuity was statistically significant (P=.02, P=.001, and P=.03, respe ctively). The increase in ocular aberrations was significantly related with the virtual pupil size. Conclusions: Photorefractive keratectomy increases the ocular aberrations, impairing the visual performance of the eyes treated. In detail, scotopic v isual measures such as low-contrast visual acuity and glare visual acuity s uffer most from the myopia correction. Aberroscopy-guided photorefractive k eratectomy may avoid such effects.