Effect of Pupillary Dilation on Corneal Optical Aberrations After Photorefractive Keratectomy

Abstract

DESPITE the proven efficacy^1-8 and widespread use of excimer laser photorefractive keratectomy (PRK) for the correction of myopia, safety remains a concern.^4,9-12 Photorefractive keratectomy has been shown to decrease contrast sensitivity,¹³ and patients can complain of glare, halos, and disturbances of night vision.^6,8,14,15 Depending on the magnitude of the attempted correction and the size of the ablation zone, past PRK studies have reported 15% to 60% of patients complaining of glare,⁶ 26% to 78% complaining of halos,^16-19 and 12% to 45% complaining of difficulty with night vision.^14,16,17,20 As many as one third of patients after PRK have been reported to be disappointed with their results despite good uncorrected visual acuity or even emmetropia.^6,14 In some studies,^4,17,18,20 up to 10% of patients who underwent PRK with an ablation zone 4.00 mm in diameter considered the problem of halos severe enough to interfere with driving at night. These complaints have led to increases in optical zone size in more recent PRK series, with the expectation of diminished visual disturbances.