Optical quality & visual performance with customised lenses for keratoconus

Abstract

Purpose: This study investigated how aberration- controlling soft contact lenses (ACCLs) corrected ocular aberrations and visual performance in keratoconic patients compared to other forms of refractive correction. Method: Twenty-two patients (16 RGP contact lens wearers and 6 spectacle wearers) were fitted with standard toric soft lenses (TCLs) and customised ACCLs (designed to correct 3rd-order coma). In the RGP lens- wearing patients, aberrations were measured without lenses, with the patient?s habitual lenses and with the study lenses (using Hartmann-Shack aberrometry). In the spectacle-wearing patients, aberrations were measured both with and without the study lenses. LogMAR visual acuity (high-contrast and low-contrast) was evaluated with the patient wearing their habitual correction (of either spectacles or RGP lenses) and with the study lenses. Results: In the contact lens-wearing patients, the habitual RGP lenses and ACCLs provided significant reductions in uncorrected 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS and higher-order RMS (HORMS) error (p?0.004). In the spectacle-wearing patients, both the TCLs and ACCLs significantly reduced uncorrected 3rd- order RMS and HORMS errors (p?0.005). The spectacle- wearing patients showed no significant differences in visual performances with their habitual spectacles versus the study lenses. In contrast, the habitual RGP lenses and TCLs provided significantly better high- contrast acuities compared to the ACCLs (p?0.006). Conclusions: In this group of keratoconic patients, ACCLs provided substantial reductions in higher-order aberrations; however, the poor visual performances achieved with the study lenses are most likely to be due to small on-eye lens decentrations.