Naso-temporal asymmetry of spatial interactions in strabismic amblyopia.
OBJECTIVE
Naso-temporal asymmetries of visual acuity and contrast sensitivity have been reported in strabismic amblyopia and attributed to asymmetries of interocular suppression. In this study, we investigated the naso-temporal asymmetry of cortical spatial interactions in two strabismic amblyopes (one esotrope and one exotrope).


METHODS
Length and width Westheimer functions were measured on both amblyopes at the 10 deg retinal eccentricity of both nasal and temporal visual fields.


RESULTS
Spatial interactions in the two amblyopic eyes were more degraded in the temporal visual fields than in the nasal visual fields. A comparison with results from the preferred eyes suggested that this asymmetry was caused mainly by a loss of spatial interactions in the temporal visual fields of amblyopic eyes, with those in the nasal visual fields being normal.


CONCLUSIONS
Our results suggest that intracortical connections underlying cortical spatial interactions might have been degraded by amblyopia. This degradation exists not only in the areas of the strabismic visual cortex responding to foveal stimuli but also in those responding to stimuli presented in the temporal visual fields.
Yu
C
C
College of Optometry, University of Houston, Texas, USA.
Levi
D M
DM
D000328:Adult; D000550:Amblyopia / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D012684:Sensory Thresholds / Q000502:physiology; D013285:Strabismus / Q000503:physiopathology*; D015357:Vision Disparity / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*