The Otago photoscreener : an investigation into pupil images

Abstract

The Otago photoscreener is a photorefractive device based on a working model constructed by Assoc. Prof. A. C. B. Molteno. It has been used for the routine screening of infants and children in Dunedin Hospital Eye Clinic since 1984. From simple ray tracing, it was predicted that the basic red fundal reflex would brighten progressively with increasing refractive error. However, some unexpected features in the fundal reflex have been observed in actual photoscreens, which have heretofor been unexplained.

This thesis presents the results of a more detailed optical analysis of retinal reflections in relation to the Otago photoscreener, and re-examines the fundal reflexes in the light of those results, so that possible origins of the features can be suggested.