Corneal first surface optical aberrations and visual performance

Wavefront analysis has demonstrated that refractive surgery-induced corneal first surface aberrations are large, are dominated by symmetric aberrations (spherical-like aberrations), and are correlated to measures of visual performance. It is not clear whether the correlation between corneal first surface aberrations and visual performance can be generalized to other corneal conditions where large asymmetric aberrations (coma-like aberrations) may dominate the aberration structure. The purpose of the research reported here was to determine the general utility of corneal first surface wavefront analysis in predicting visual performance.

Patients were 13 normals and 78 patients with a variety of corneal conditions including surgically removed pterygia, penetrating keratoplasty, keratoconus, radial keratotomy, laser in situ keratomileusis, and others. Videokeratographs were taken for all patients and used to calculate corneal first surface wavefront variance for 3 and 7 mm pupils. Similarly, visual performance was quantified by measurements of contrast sensitivity and high and low contrast acuities through both 3 and 7 mm pupils.

Statistically significant correlations existed between all three measures of visual performance and the corneal wavefront variance. All relationships were stronger for the 7 mm diameter-pupil condition than the 3 mm pupil.

Regardless of the cause, corneas with increased wavefront variance showed a quantifiable decrease in visual performance that was pupil size dependent.