Translator Disclaimer
20 September 2002 Optical Analysis for Light Intensity Distribution in EPR with Different Light Sources
Author Affiliations +
Eccentric photorefraction is an objective refraction technique that, by taking a picture of the pupil of the subject, can measure refractive errors in human eyes. The method assessing the refractive errors is mainly from the size and orientation of the crescent of the pupil image. Because of the effects of the light source and the vignetting of the optical system’s aperture, the boundary of the crescent is not sharp so as to accurately determine its size. This uncertainty reduces the accuracy of the EPR system and limits its extensive application. In this paper, analysis on the light intensity distribution across the pupil is presented. It aims to determine the size of the crescent based on the aperture opening in the form of straight edge, rectangle and slit are also included in discussion. The analysis shows that the EPR system with a line source and a rectangular aperture opening will give a good linear light distribution profile across the pupil, which may be helpful to automatically determine the size of the crescent. The method will effectively improve the measurement accuracy of EPR.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Xiangning Li, Liner Zou, Longyun Xu, Jiabi Chen, and Yi Wang "Optical Analysis for Light Intensity Distribution in EPR with Different Light Sources", Proc. SPIE 4927, Optical Design and Testing, (20 September 2002);


Early screening of an infant's visual system
Proceedings of SPIE (June 18 1999)
Digital photorefraction
Proceedings of SPIE (January 01 1998)
Intensity distribution topography on pupil’s image in EPR
Proceedings of SPIE (February 10 2005)

Back to Top