Visual performance and optical quality of standardized asymmetric soft contact lenses in patients with keratoconus

Abstract

PURPOSE. To evaluate the visual performance and optical quality of a standardized asymmetric soft contact lens (SCL) used for correction of higher-order aberrations (HOAs) in eyes with keratoconus. METHODS. We included 30 eyes (26 patients) with keratoconus (average K: 45.7 ± 2.3 diopters [D]). The patients were subjected to corneal tomography, aberrometry, measurements of manifest refraction and visual acuity (VA), and visual analog scale (VAS) assessments. The study lenses were made using a molding method and consisted of six standardized types, in which an asymmetric power distribution of approximately 2 to 12 D (2-D step) was used to correct HOAs. The lens type suitable for each eye was selected based on the corneal tomography and aberrometry data. The on-eye performance of the lens was evaluated using aberrometry (4-mm pupil), over refraction, VA, and VAS. RESULTS. The standardized asymmetric SCL improved the best spectacle-corrected VA from 0.07 ± 0.09 to 0.11 ± 0.08 logMAR (P < 0.05) and the mean VAS score from 66.2 ± 21.8 to 75.4 ± 20.5 (P < 0.05). Vertical coma decreased significantly (0.50 ± 0.36 μm without SCL; 0.36 ± 0.34 μm with SCL; P < 0.01). In subgroup analysis, subjects in the high VAS group (score ≥ 75) accounted for 70% of all subjects, and this was the group in which the vertical coma decreased significantly from the level without the lens. CONCLUSIONS. A standardized asymmetric SCL can reduce HOAs and improve vision quality when compared with spectacles in patients with keratoconus who wear rigid gas-permeable lenses.