Spatiotemporal 2-dimensional gabor (ST2DG): A PC-based test for assessment of spatiotemporal contrast sensitivity

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Abstract

Purpose. To design a screening test of the spatiotemporal contrast surface, using intrinsically two-dimensional spatial targets, and explore its diagnostic power beyond currently used spatial and temporal contrast sensitivity measurement tools. Methods. Circular sine wave gratings, with contrast tapered off according to a gaussian profile, and sinusoidally counterphase modulated with a ramped on-and offset are presented on a high-resolution 60 Hz monochrome monitor screen driven by an Imagraph 12108 board. A four-alternative spatial alternative paradigm is employed - i.e., the subject is required to indicate towards which corner the pattern is displaced -. Fifteen combinations of 5 spatial - from 4.3 to 0.3 octaves below the subject's acuity limit - and 6 temporal - from 1 to 30 Hz - frequencies are used. Thresholds are computed by fitting a Weibull function through data obtained with 10 reversals of a 2-down 1-up staircase Results. Naive observers can complete the test in 30-45 minutes. Data from the initial 10 normal observers show excellent agreement with data from Kelly (JOSA 69, 1340-9), with the expected more rapid drop-off at higher two- vs one-dimensional spatial frequencies. Data from 14 RP subjects at various stages of disease progression show interactions of spatial and temporal loss that are more severe than would be expected on the basis of spatial and temporal contrast sensitivity measurements alone. Tests in subjects with various forms of macular dysfunction are in preparation. Conclusions. The technique presented here allows automated assessment of spatiotemporal contrast sensitivity, with the potential to develop a screening tool for normal development and a variety of retinal diseases.

Original languageEnglish (US)
Pages (from-to)S733
JournalInvestigative Ophthalmology and Visual Science
Volume37
Issue number3
StatePublished - Feb 15 1996

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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