QUANTITATIVE ASSESSMENT OF LATERAL INTERACTION AS DETERMINED BY COMPUTERIZED QUANTITATIVE LAYER-BY-LAYER PERIMETRY

Background: Quantitative layer-by-layer perimetry is a psychophysical technique which assesses lateral interaction in human vision. In prior designs of this technique the test procedure was time-consuming and q uantitative assessment of the results was not possible. In order to sh orten test duration and provide quantitative experimental data, a new computerized version of the technique has recently been developed. Met hods: A mathematical model for describing lateral interaction as asses sed by computerized quantitative layer-by-layer perimetry was develope d, and experimental data from the testing of 18 normal persons were fi tted to the model. Two descriptive parameters of, respectively, latera l stimulation and lateral inhibition were for each test point related to the differential light sensitivity and to the eccentricity in the v isual field. Results: The two parameters describing lateral stimulatio n could not be reliably estimated. However, the two parameters describ ing lateral inhibition showed, respectively, a positive correlation wi th the differential light sensitivity in the visual field and a signif icant decline with increasing eccentricity in the visual field. Conclu sion: The technique and the mathematical model employed are suitable f or quantitative assessment of lateral inhibition in human vision.