Abstract
Presentation Description :
The visual image on the retina contains different sources of visual information: e.g., wavelength, spatial frequency, temporal frequency, motion, contrast, and scale. Diseases of the retina affect the ability of the early visual system to receive, process, and successfully transmit this information to later stages of visual processing. One goal of clinical psychophysics is to measure responses to visual stimuli in such a way as to detect, differentiate, and track the progress of specific clinical conditions based on how patients see (i.e., at a functional level). The task of psychophysics is difficult because creating stimuli that isolate individual processes is complicated, and because most diseases of the eye are not selective to one type of mechanism. Our laboratory has argued that there is a need to think creatively when designing a stimulus so as to separate responses to different types of visual information. To this end, we present techniques and phenomena that demonstrate many ways to think more broadly about the parallel nature of information processed by the early visual system, and how such information can be used to assess visual function in clinical populations. The presentation will concentrate on four classes of separations: 1. A separation between luminance and luminance contrast (contrast asynchrony: Shapiro, 2008); 2. Techniques that show that small changes in contrast amplitude can lead to the perception of motion (diamond motion: Flynn and Shapiro, submitted; Nigam, Hedjar, and Shapiro, 2016);
3. Methods for separating motion signals that are available to the fovea but not to the periphery (Shapiro, Knight, and Lu, 2011); and 4. Methods based on the integration of low and high spatial frequency content (Dixon and Shapiro, 2017). We show that stimuli that place sources of visual information in conflict with each other can isolate different types of visual responses. And we show that these types of stimuli are likely to produce clinically relevant visual tests.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.