Abstract
The visualization of the location of stimuli on the retina during visual function tasks provides more detailed information both for basic vision research and diagnosis and prognosis in retinal disease. A new prototype of the Digital Light Ophthalmoscope (DLO) provides near infrared imaging of the retina, using virtually invisible 860 nm illumination with 160 uW at the cornea, provided by a vertical cavity surface emitting laser. The DLO uses a digital light projector for pseudo-scanning the illumination across the retina. When the illumination lines are synchronized with the rolling shutter of a CMOS camera, high contrast retinal images are obtained. Shifting the timing of the illumination lines and the read-out of the CMOS detector allows a wide variety of imaging conditions, including confocal and multiply scattered light modes. The NIR DLO acquires 1024×1024 pixel images over a 14.2 deg field of view. Superimposed is a 1920×1080 LCD display, providing 8 bit per channel RGB images in Maxwellian view, with a 0.5 min arc resolution so that 20/10 visual acuity targets or complex scenes can be displayed. Retinal images are digitized, and aligned in post-processing to identify target locations on the retina. Five undilated subjects (27 – 59 yr) with a wide range of fundus pigmentation and refractive error read aloud 4 lines (20/40 – 20/10) from a tumbling E chart while being continuously imaged. In confocal images, the foveal location was pinpointed in real time by the weak bow tie due to the Henle fibers. In scattered light images, drusen were revealed.