Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group

Optics of photorefraction: orthogonal and isotropic methods

Not Accessible

Your library or personal account may give you access

Abstract

Analysis of the optics of photorefractively computed ray tracing shows that, for short camera-to-subject distances, the function relating image size to defocus of the eye is not symmetrical for errors of focus in front of and behind the camera. This asymmetry is exploited in the new method of isotropic photorefraction, in which the supplementary cylinder lenses of the original orthogonal photorefractors are replaced by defocusing of the camera lens itself. By comparing photographs taken with the camera focused in front of and behind the subject, the sign of the eyes’ defocus (myopic or hyperopic relative to the camera) can be determined. The axis of any astigmatism is readily apparent as the direction in which the photorefractive images are elongated. The method is well adapted for the refractive screening of infants and young children.

© 1983 Optical Society of America

Full Article  |  PDF Article
More Like This
Photorefraction: A technique for study of refractive state at a distance

Howard C. Howland and Bradford Howland
J. Opt. Soc. Am. 64(2) 240-249 (1974)

Coaxial photorefractive methods: an optical analysis

W. R. Bobier, Melanie C. W. Campbell, C. R. McCreary, A. M. Power, and K. C. Yang
Appl. Opt. 31(19) 3601-3615 (1992)

Effect of monochromatic aberrations on photorefractive patterns

Melanie C. W. Campbell, W. R. Bobier, and A. Roorda
J. Opt. Soc. Am. A 12(8) 1637-1646 (1995)

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (11)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Equations (2)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved