Purpose: To investigate the impact of corneal higher-order aberrations (HOAs) on predicted corrected distance visual acuity (CDVA) in patients with keratoconus at varying simulated pupil apertures.
Setting: Ophthalmology clinics, Medical University of South Carolina, USA.
Design: Retrospective chart review study.
Methods: 56 eyes with keratoconus were examined using Scheimpflug tomography during routine examinations prior to medical intervention. The severity of keratoconus was graded using the Amsler-Krumeich classification. Zernike analysis was used to obtain corneal aberrations using simulated pupil diameters of 6-, 4-, and 2 mm. These data were extrapolated to obtain the total RMS HOAs for a 1.6 mm simulated pupil to evaluate the potential effect of a small aperture intraocular lens. Correlation analysis was used to study the impact and relative contributions of HOAs on CDVA. Convolution of HOAs from OPD-Scan III (NIDEK) provided a clinical method to predict CDVA with different simulated pupil sizes in corneas with irregular astigmatism.
Results: There were statistically significant positive correlations between photopic CDVA and the magnitude of total and individual (coma, spherical aberration and trefoil) HOAs in this cohort of keratoconus subjects. A keratoconus case with the small aperture IOL confirms the improvement in vision due to the pinhole effect.
Conclusions: The small aperture IOL is expected to markedly reduce aberrations in keratoconus patients up to Amsler-Krumeich class 4 severity to levels consistent with the levels seen in healthy patients. Convolution of corneal HO aberrations with the ETDRS chart provides a useful simulation of the impact of pinhole optics in aberrated eyes.
Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of ASCRS and ESCRS.