Performance of Wavefront-Guided Soft Lenses in Three Keratoconus Subjects

Abstract

Purpose-To examine if custom wavefront-guided soft contact lenses provide visual and optical performance equivalent to habitual gas permeable (GP) corrections in three keratoconus subjects.Methods-Custom wavefront-guided soft contact lenses were produced and evaluated at the Visual Optics Institute, College of Optometry, University of Houston for three habitual GP-wearing keratoconus subjects. Photopic high and mesopic low contrast logMAR visual acuity and residual 2nd-10th order optical aberrations experienced with these custom soft lenses were recorded and compared to the subjects' habitual GP correction.Results-All three subjects wearing custom soft lenses reached the established exit criterion of photopic high contrast logMAR VA equal to or better than values recorded with their habitual GP lens. High contrast logMAR VA for GP and custom soft lens correction was 0.01±0.05 and 0.00 ±0.02 for KC1, 0.20±0.02 and 0.14±0.02 for KC2 and 0.04±0.09 and −0.05±0.05 for KC3 respectively. Additionally, KC2 reached the exit criterion of high order aberration levels equal to or less than values with their habitual GP lens (GP lens: 0.394 ± 0.024μm, custom lens: 0.381 ± 0.074μm).Conclusions-Custom wavefront-guided soft contact lenses have been demonstrated to provide equivalent photopic high contrast logMAR VA to that achieved with habitual GP correction in three keratoconus subjects. Future emphasis will be placed on surpassing habitual GP performance and reaching a normal age-matched criterion for both visual acuity and aberration measures. Achieving these goals may require a more thorough understanding of the relationship between visual performance and residual aberration experienced during custom lens wear through the use of image quality metrics predictive of visual performance. Keywordskeratoconus; Zernike; wavefront; wavefront-guided; soft contact lens; rigid contact lens; aberration Elevated levels of both lower and higher order aberrations present in the eye disease keratoconus make it difficult for subjects to achieve excellent optical and visual performance with traditional soft contact lenses or spectacles. Consequently, rigid contact lenses have become the current gold standard for the correction of keratoconus, with approximately 65% of keratoconus subjects being fitted with some form of rigid lens correction in both eyes. 1 Rigid lenses reduce unwanted aberrations where conventional soft lenses and spectacles fail due to the ability of the rigid lens to maintain its shape during wear. This results in the formation of a tear lens between the aberrated cornea and rigid lens which masks a portion of the aberration present in these highly aberrated eyes. However, prescribing a rigid lens may not decrease higher order aberration to normal levels, and the elevated levels of residual aberration may continue to have a negative impact on visual performance. 2-4Simulation work in the area of customization has demonstrated that customized correction of lower and higher order aberrations in the keratoconic eye w...

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Visual Performance and Optical Quality of Standardized Asymmetric Soft Contact Lenses in Patients With Keratoconus

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Advances in Retinal Imaging

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