A new noninvasive imaging technique for cataract evaluation in the rhesus monkey.

We present the first in vivo study using Optical Coherence Tomography (OCT)' as the imaging device for lenticular cataracts in the geriatric rhesus monkey. OCT is a non-invasive imaging technique that produces a two dimensional cross sectional image of intraocular tissue similar to ultrasound B scan. In OCT the images are formed by measuring optical reflections from the tissue. Eighteen geriatric subjects with documented lenticular opacities and one control subject were imaged. The OCT images produced are compared to current and previous clinical cataract grading exams and slit-lamp photography. Histopathology was collected on one subject and is compared to the OCT image. OCT provides information on nuclear, cortical and subcapsular opacities. The image information is presented based on a color coded computer generated log reflective scale. The log reflective scale is converted to a qualitative grading system. Although movement and shadow artifact can occur, these are readily identifiable and can be differentiated from underlying lenticular abnormalities. OCT has great potential to assist in further characterization of cataracts.