Impact of Zernike-fit error on simulated high- and low-contrast acuity in keratoconus: implications for using Zernike-based corrections
This study examines the extent to which a Zernike-based optical correction can restore acuity in keratoconus as a function of disease severity and contrast level. Increasingly complete Zernike corrections in the presence of Zernike fit error were simulated.
Acuity for keratoconic eyes with P<60D maximum corneal power reached 20/13 with a fifth-order Zernike correction under high contrast conditions and exhibited a loss of 0.1 logMAR (20/32 to 20/40) for low contrast conditions.
Acuity for keratoconic eyes with >60D maximum corneal power approached 20/13 with sixth-tenth-order corrections under high contrast conditions, but did not return to similar levels with a tenth-order correction for low contrast conditions.
The results suggest that fit error impacts visual performance for more difficult tasks and that restoring high contrast acuity (20/16 or better) using a fifth-order Zernike correction is not limited by Zernike fit error for over 85% of keratoconus cases.
OCIS codes: 330.1070 (acuity), 330.4060 (modeling of vision), 330.5370 (physiological optics)
Journal of Optical Society of America, Vol 23, No 4, April 2006; 769-776.
Jason D. Marsack
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