The Development of the Generation II as an Aid for Patients with Retinitis Pigmentosa and Night Blindness

Evaluation of the Night Vision Spectacles on patients with impaired night vision

“…Most of these incorporate photomultipliers and have been designed to improve night vision in subjects with normal rod function. They may also be suitable for patients with impaired or nonfunctioning rod vision [1,5,7,9,14], provided that the output luminance exceeds the patient's absolute threshold. While such devices enhance luminance over the entire image plane simultaneously, they leave contrast basically unchanged.…”

“…Most of the devices use photomultipliers to amplify the ambient light; some also incorporate infrared light sources to increase illumination if the ambient light level is too low. However, none of these devices were specifically designed, and only a few have been tested [1,5,7,9,14], for use at night by patients with disturbances of rod vision.…”

“…They consist of a head-mounted video camera (input) and binocular displays (output) connected to a portable computer processor, which uses an algorithm to enhance the luminance and contrast of the video image. l Methods: Eighteen patients with impaired night vision were tested, including those with retinitis pigmentosa (7), Usher syndrome (2), fundus albipunctatus (1) and complete (4) and incomplete (4) congenital stationary night blindness. Normal trichromats (3) and typical, complete achromats (2) acted as controls.…”

Connecting Research on Retinitis Pigmentosa to the Practice of Orientation and Mobility

“…Another strategy for managing night blindness is the use of night vision technology (Berson, Mehaffey, & Rabin, 1974;Davidson, Echols, & Jose, 1976;Hoover, 1983), in the form of what is generically called night scopes. Introduced in the early 1960s for use in the Vietnam War, these devices are now sold widely at relatively low prices.…”

The Effect of Colour Output of Intensifying Devices on Acuity in Pigmentary Retinal Degeneration

“…The patients used in the studies were suffering from either pigmentary degeneration of the retina or congenital stationary night blindness. Davidson et al (1976) reviewed the literature available on night blindness and light intensifiers before reporting an investigation into mobility using a light intensifier similar to that used by Berson. The study required normal subjects to compete against subjects with deficient night vision over an obstacle course in conditions of low illumination.…”