Optical quality and visual performance with customised soft contact lenses for keratoconus.
OBJECTIVE
This study investigated how aberration-controlling, customised soft contact lenses corrected higher-order ocular aberrations and visual performance in keratoconic patients compared to other forms of refractive correction (spectacles and rigid gas-permeable lenses).


METHODS
Twenty-two patients (16 rigid gas-permeable contact lens wearers and six spectacle wearers) were fitted with standard toric soft lenses and customised lenses (designed to correct 3rd-order coma aberrations). In the rigid gas-permeable lens-wearing patients, ocular aberrations were measured without lenses, with the patient's habitual lenses and with the study lenses (Hartmann-Shack aberrometry). In the spectacle-wearing patients, ocular 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 rigid gas-permeable contact lenses) and with the study lenses.


RESULTS
In the contact lens wearers, the habitual rigid gas-permeable lenses and customised lenses provided significant reductions in 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS and higher-order RMS error (p ≤ 0.004). In the spectacle wearers, the standard toric lenses and customised lenses significantly reduced 3rd-order RMS and higher-order RMS errors (p ≤ 0.005). The spectacle wearers showed no significant differences in visual performance measured between their habitual spectacles and the study lenses. However, in the contact lens wearers, the habitual rigid gas-permeable lenses and standard toric lenses provided significantly better high-contrast acuities compared to the customised lenses (p ≤ 0.006).


CONCLUSIONS
The customised lenses provided substantial reductions in ocular aberrations in these keratoconic patients; however, the poor visual performances achieved with these lenses are most likely to be due to small, on-eye lens decentrations.
Faculty of Life Sciences, The University of Manchester, Manchester, UK.
Amit
A
Jinabhai
Clare
C
O'Donnell
Cindy
C
Tromans
Hema
H
Radhakrishnan
D000328:Adult; D000704:Analysis of Variance; D003261:Contact Lenses; D003263:Contact Lenses, Hydrophilic; D015350:Contrast Sensitivity; D057108:Corneal Wavefront Aberration / Q000209:etiology / Q000628:therapy; D005139:Eyeglasses; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
aberration-controlling contact lenses; coma aberrations; higher-order aberrations; keratoconus; rigid gas-permeable contact lenses; toric soft contact lenses