The high prevalence of cataracts is still a serious public health problem as a leading cause of blindness, especially in developing countries with limited health facilities. In this paper we propose a new screening method for cataract diagnosis by easy-to-use and low cost imaging equipment such as commercially available digital cameras. The difficulties in using this sort of digital camera equipment are seen in the observed images, the quality of which is not sufficiently controlled; there is no control of illumination, for example. A sign of cataracts is a whitish color in the pupil which usually is black, but it is difficult to automatically analyze color information under uncontrolled illumination conditions. To cope with this problem, we analyze specular reflection in the pupil region. When an illumination light hits the pupil, it makes a specular reflection on the frontal surface of the lens of the pupil area. Also the light goes through the rear side of the lens and might be reflected again. Specular reflection always appears brighter than the surrounding area and is also independent of the illumination condition, so this characteristic enables us to screen out serious cataract robustly by analyzing reflections observed in the eye image. In this paper, we demonstrate the validity of our method through theoretical discussion and experimental results. By following the simple guidelines shown in this paper, anyone would be able to screen for cataracts.

Date Published: 17 March 2008
PDF: 12 pages
Proc. SPIE 6915, Medical Imaging 2008: Computer-Aided Diagnosis, 69152Z (17 March 2008); doi: 10.1117/12.770069

Published in SPIE Proceedings Vol. 6915:
Medical Imaging 2008: Computer-Aided Diagnosis
Maryellen L. Giger; Nico Karssemeijer, Editor(s)