Measurement of temporal contrast sensitivity
Dimofte, A.-D.; Dimofte, G.
Oftalmologia 57(2): 81-88
2003
ISSN/ISBN: 1220-0875 PMID: 12974037 Document Number: 554186
The main objective is to present a new prototype designed to test temporal contrast sensitivity, using a flicker stimulus. We used a radiant surface manufactured with light emitting diode having a dominant wave-length of 626 nm, producing a light spot projected in the central visual field (320). The system uses a flicker stimulus with parameters (light intensity and frequency) that can be varied using a computer. The test group (24 healthy subjects) gave us the possibility to evaluate the test response, to optimise the testing protocol and draw the specific de Lange curve. The test has a very good reproducibility with less then 1% variations between measurements. Distribution of temporal contrast sensitivity follows the de Lange classic curve, the frequencies tested in this experiment being situated on the platou of the curve. We preferred to express the results as minimal light intensity. Within 10 Hz to 30 Hz the results demonstrate little dispersion, with a standard deviation of 0.8% and 2.1% for maximal light intensity of 100% and 50% respectively. We consider that the prototype can be used for testings of the temporal contrast sensitivity for the central visual field (central 320). The device is simple to use and can well accommodate for outpatient evaluations. We hope that our prototype will be used to monitor minimal changes in the response of the visual system to flicker stimuli.