title: Lateral Inhibition in the Human Visual System in Patients with Glaucoma and Healthy Subjects: A Case-Control Study.
abstract: In glaucoma, the density of retinal ganglion cells is reduced. It is largely unknown how this influences retinal information processing. An increase in spatial summation and a decrease in contrast gain control and contrast adaptation have been reported. A decrease in lateral inhibition might also arise. This could result in a larger than expected response to some stimuli, which could mask ganglion cell loss on functional testing (structure-function discrepancy). The aim of this study was to compare lateral inhibition between glaucoma patients and healthy subjects; we used a case-control design. Cases (n = 18) were selected to have advanced visual field loss in combination with a normal visual acuity. Controls (n = 50) were not allowed to have symptoms or signs of any eye disease. Lateral inhibition was measured psychophysically on a computer screen, with (1) a modified illusory movement experiment and (2) a contrast sensitivity (CS) test. Illusory movement was quantified by nulling it with a real movement; measure of lateral inhibition was the amount of illusory movement. CS was measured at 1 and 4 cycles per degree (cpd); measure of lateral inhibition was the difference between log CS at 4 and 1 cpd. Both measures were compared between cases and controls; analyses were adjusted for age and gender. There was no difference between cases and controls for these two measures of lateral inhibition (p = 0.58 for illusory movement; p = 0.20 for CS). The movement threshold was higher in cases than in controls (p = 0.008) and log CS was lower, at both 1 (-0.20; p = 0.008) and 4 (-0.28; p = 0.001) cpd. Our results indicate that spatially antagonistic mechanisms are not specifically affected in glaucoma, at least not in the intact center of a severely damaged visual field. This suggests that the structure-function discrepancy in glaucoma is not related to a decrease in lateral inhibition.
authors.affiliation: Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
authors.forename: Francisco G
authors.initials: FG
authors.lastname: Junoy Montolio
authors.affiliation: Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
authors.forename: Wilma
authors.initials: W
authors.lastname: Meems
authors.affiliation: Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
authors.forename: Marieke S A
authors.initials: MS
authors.lastname: Janssens
authors.affiliation: Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
authors.forename: Lucas
authors.initials: L
authors.lastname: Stam
authors.affiliation: Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.|Dept. of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands.
authors.forename: Nomdo M
authors.initials: NM
authors.lastname: Jansonius
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D015350:Contrast Sensitivity; D005260:Female; D005901:Glaucoma / Q000503:physiopathology* / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D014792:Visual Acuity; D014794:Visual Fields; D014796:Visual Perception