Theoretical interpretation and derivation of flash-on-flash threshold parameters in visual system diseases

Robert W. Massof, Sergiu Marcus, Gislin Dagnelie, David Choy, Janet Sunness, Michael Albert

Research output: Contribution to journalArticle

Abstract

Visual increment thresholds measured on backgrounds flashed on simultaneously with the test flash exhibit saturation rather than following Weber's law. These flash-on-flash thresholds have been modeled with saturating nonlinearities similar to those used to describe intensity-response functions of retinal neurons. Recently, the flash-on-flash technique has been used to assess the mechanisms of threshold elevations in visual system diseases. However, the results were interpreted in a qualitative way. This paper extends the clinical application of flash-on-flash threshold measures by providing a theoretically derived algorithm for estimating nonlinear model parameters from flash-on-flash threshold data. The performance of the algorithm is evaluated with Monte Carlo techniques, and the theoretical interpretations of the model parameters aretested experimentally. Published clinical flash-on-flash threshold data are reanalyzed using the algorithm. A previously unappreciated decrease in the half-saturation constant of retinitis pigmentosa patients was revealed by this analysis.

Original languageEnglish (US)
Pages (from-to)1014-1024
Number of pages11
JournalApplied Optics
Volume27
Issue number6
DOIs
StatePublished - Mar 15 1988

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering

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