Abstract

The eye's pupil defines the area of each optical surface used to form the retinal image. Intervention (e.g., radial keratotomy, photorefractive keratectomy, displaced IOL) and/or pathology (e.g., corneal degeneration or scarring) can markedly change the optical properties of the eye and aggravate or improve visual performance as a function of pupil size. The following constraints make measurement of these properties difficult: 1) the use of an artificial pupil placed in front of the eye, as opposed to natural pupil plane; 2) selection and maintenance of a relevant reference axis; and 3) selection and quantification of a reasonable psychophysical task. We address these constraints by employing 1) a Maxwellian view system with a variable exit pupil diameter imaged in the plane of the eye's entrance pupil; 2) a Thibos foveal achromatic alignicator to define the reference axis; and 3) a high contrast Bailey-Lovie acuity chart and a fixed letter scoring criteria. Measurements on patients prior to and after radial keratotomy and photorefractive keratectomy demonstrate that best corrected visual acuity is generally decreased following intervention for large pupils and is generally unchanged for small pupils.

© 1992 Optical Society of America