Comparing continuous and stepwise luminance variation in static campimetry using the Grignolo-Tagliasco-Zingirian projection campimeter.

In traditional static perimetry the remarkable precision achieved, resulting mainly from the lack of temporal factors related to latency, largely makes up for the relatively long time required to perform the test. Conversely, the increase in speed of the test and in the information content of the visual field charts counteract the lower precision attained with kinetic perimetry. If the influence of the latency time on responses could be kept at a low value, then adopting a static strategy, based on a continuous rather than discrete target luminance variation for threshold detection, could be justified. For this purpose a luminance variation time sequence designed to reproduce the conditions of the traditional static perimetric test was chosen. The test was performed on the Grignolo-Tagliasco-Zingirian projection campimeter, after comparing its clinical performance with the Goldmann perimeter. These two methods - one based on continuous variation, the other based on discrete target luminance variation - were compared using a 14-subject sample. We conclude that the presentation strategy based on continuous luminance variation can be regarded as a valid alternative to the traditional method.