Schematic diagram of a retinal optical imaging camera, based on a modified Topcon fundus camera. The retina is illuminated with near infrared (NIR) light (λi, 700–900 nm; typical, 750 nm) generated by the built-in tungsten lamp (W). The reflected NIR light is filtered to block any out-of-band light before being collected by the CCD camera. Visible patterned stimuli are generated by a small LCD module, filtered (λs, typically 540 nm green), and reflected into the light path projected onto the retina via a dichroic (cold) mirror. PS, power supply; PC, personal computer; Xe, Xenon flashlamp.