Retinal Photometer Final Design Review

• Main Author: Castro, Layne Arin
• Other Authors: Arabyan, Ara
• Language: en
• Published: The University of Arizona. 2013
• Online Access: http://hdl.handle.net/10150/297519

The main objective of the retinal photometer is to detect visual changes in the retina before irreversible damage can occur. The handheld photometer is fitted with a small light source surrounded by a circular pattern of LEDs. The central LED is focused into the fovea of the retina by a single lens. The lens can adjust to account for various visual acuities. The momentary light pulse induces photobleaching, a harmless process of temporarily blinding the fovea similar to the temporary blindness of walking into the sun after being in a dark space. The photometer will then record the amount of time it takes for full eyesight regeneration on the onboard LCD screen using a timer, which is programmed and wired through a self-contained circuit. Recovery times, interpreted by a medical professional, are shorter in healthy eyes than in eyes with macular degeneration. If increased response times are observed, a different lens can be inserted to decrease the spot size of the LED to pinpoint the severely damaged areas of the macula. Additionally, the circular pattern of LEDs tests visual sensitivities of off-center vision. Diabetic retinopathy or macular edema is likely if the patient cannot detect the full arrangement of LEDs.