Customized hydrogel contact lenses for keratoconus incorporating correction for vertical coma aberration

Abstract

To study the effects on visual performance of a novel custom hydrogel contact lens, which employs a correction for vertical coma aberration, in keratoconic eyes. Six subjects (8 eyes) with mild or moderate keratoconus were recruited for the study. Preliminary measurements included corneal topography, wavefront aberrometry, subjective refraction, visual acuity (VA) and 50% contrast VA. Based on the aberrometry data, customized lenses were made and fitted to the subjects. Evaluation of the on-eye performance of the lenses was carried out, including wavefront aberrometry, over-refraction, VA and 50% contrast VA. In two of the subjects, both eyes were fitted with the customized lenses, and binocular performance was evaluated. Monocular visual performance with a 4 mm pupil, with the lenses worn, was improved, and reached the mean values of -0.003 (LogMar units) of 100% high contrast VA, and 0.049 (in LogMar units) of 50% contrast VA. Vertical coma aberration and total higher-order aberrations (HOAs) were reduced (naked eyes: -0.64 +/- 0.21 root mean square (rms) of vertical coma and 0.86 +/- 0.15 rms of total HOAs; with the lenses worn: -0.29 +/- 0.23 rms of vertical coma and 0.57 +/- 0.17 rms of total HOAs, all for a 4 mm pupil). Binocular VA results from two of the subjects were on average -0.040 (LogMar units) 100% high contrast acuity and -0.060 (LogMar units) 50% contrast visual acuity. Customized hydrogel contact lenses implementing correction of vertical coma, have been found to improve both monocular and binocular visual performance of eyes affected with mild or moderate keratoconus.