VALIDATION OF LASER-DOPPLER INTERFEROMETRIC MEASUREMENTS IN-VIVO OF AXIAL EYE LENGTH AND THICKNESS OF FUNDUS LAYERS IN CHICKS

Purpose. Laser Doppler interferometry (LDI) permits the measurement of intraocular distances to a precision of better than 20 mu m. The sign al complex from the posterior segment of the eye consists of four peak s in the chick, an animal frequently used in ocular development studie s. The present study sought to identify anatomical landmarks correspon ding to these LDI peaks. Methods. Distances obtained with LDI at the p osterior pole were compared to axial length components measured with t hree independent methods: vernier calipers, tissue sections and high f requency A-scan ultrasound. Results. LDI reflections appear to origina te from the retinal inner limiting membrane, Bruch's membrane and the inner and outer scleral surfaces. Conclusions. The non-invasive and hi ghly precise nature of LDI measurements enables repetitive and accurat e assessment of intraocular distances. Such measurements should prove particularly useful for the assessment of short-term cyclic variations in intraocular distances as well as post-natal eye growth.