Purpose. Binocular performance in the central and peripheral visual fields
was compared for normal and anisometropic amblyopes.
Methods. Binocular and monocular thresholds to a light detection task were
measured along the four principal meridia in 10 young normal subjects and 1
0 anisometropic amblyopes using the Humphrey's Visual Field Analyser. Thres
holds were obtained at the fovea and at retinal eccentricities of 5 degrees
, 10 degrees, 15 degrees, 25 degrees, 40 degrees and 55 degrees on the hori
zontal, vertical and oblique meridia of 45 degrees and 135 degrees.
Results. Binocular summation ratios (binocular sensitivity/'best' monocular
sensitivity) were calculated for all the eccentricities. In the normal gro
up, the mean binocular summation ratio for the fovea and the peripheral fie
ld was not significantly different. In the amblyopic group, subjects showed
no or minimal binocular summation in the foveal region but reached normal
ratios in the periphery.
Discussion. Results are discussed in terms of tolerance to interocular sens
itivity differences in the periphery and selective losses in cortical cells
.