Lateral Inhibition in the Human Visual System in Patients with Glaucoma and Healthy Subjects: A Case-Control Study

• Published in: PloS one Vol. 11; no. 3; p. e0151006
• Main Authors: Junoy Montolio, Francisco G., Meems, Wilma, Janssens, Marieke S. A., Stam, Lucas, Jansonius, Nomdo M.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 08.03.2016; Public Library of Science (PLoS)
• Subjects: Acuity; Age; Aged; Analysis; Biology and Life Sciences; Care and treatment; Case-Control Studies; Compounds; Contrast Sensitivity; Data processing; Experiments; Female; Functional testing; Glaucoma; Glaucoma - physiopathology; Glaucoma - psychology; Humans; Information processing; Inhibition; Male; Medical research; Medicine and Health Sciences; Middle Aged; Patients; Physical Sciences; Retina; Retinal ganglion cells; Social Sciences; Structure-function relationships; Visual Acuity; Visual field; Visual Fields; Visual Perception; Visual system; United States > US; Netherlands; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0151006

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.