Eye tester using stimulating light - has brightness continuously varied according to mathematical function, contrast remains constant

摘要

Eye testing apparatus uses light to stimulate the eye or retina, and then obtain a graphical representation of the resulting signals. The brightness of the optical stimulator is continuously varied and the signals obtained are calculated according to a mathematical function, in dependence upon the brightness. The fixation light always has the same contrast against the background. Amplitude measurements are made at given time intervals, and the voltages resulting are indicated on a scale. The light source is intensity modulated by a signal by means of an optical/electronic converter to obtain a function signal. The original brightness signal is compared with the processed signal and a difference signal between maximum and minimum values is obtained and measured.