Abstract
Purpose:
To study the visual performances of a novel silicone-hydrogel soft contact lens (Si-SCL), which was designed to correct a refractive vertical asymmetry in keratoconic eyes.
Methods:
Fifty eyes of 37 subjects with mild keratoconus were recruited for the study. Measurements included corneal anterior optical coherence tomography (SS-1000, Tomey), wavefront aberrometry (KR-1W, Topcon), subjective refraction, visual acuity (VA), visual clarity with visual analog scale (VAS). Study lenses were made by molding method and were consisted of 6 types, in which asymmetrical power distribution (2D, 4D, 6D, 8D, 10D, 12D) was created to correct vertical irregular astigmatism. Based on the topography and aberrometry data, the type of lenses was selected and fitted to the subjects. Evaluation of the on-eye performance of the lens was carried out, including wavefront aberrometry (4mm pupil, root mean square), over-refraction, VA, visual clarity with VAS.
Results:
Monocular visual performance with a Si-SCL improved from -0.03±0.13 to -0.08±0.08 LogMAR in VA (p<0.01), from 61.2±20.7 to 73.8±18.5 VAS scores in vision clarity (p<0.01). Vertical coma-aberration and total higher-order aberrations (HOAs) were reduced {naked eyes: -0.49±0.36 µm in vertical coma and 0.66±0.39 µm in HOAs; with the lenses: -0.35±0.38 µm in vertical coma (p<0.05) and 0.61±0.39 µm in HOAs (p<0.05)}.
Conclusions:
A novel Si-SCL designed to correct refractive vertical asymmetry has improved the monocular visual performance as well as the degree of vertical coma in eyes with keratoconus.
Keywords: 477 contact lens •
574 keratoconus •
626 aberrations