PURPOSE. Binocular performance in the central andperipheral visual fields was compared for normal and anisometropic amblyopes. METHODS. Binocular and monocular thresholds to a light detection task weremeasured along the four principal meridia in 10 young normal subjects and10 anisometropic amblyopes using the Humphrey's Visual Field Analyser. Thresholdswere obtained at the fovea and at retinal eccentricities of 5º, 10º,15º, 25º, 40º and 55º on the horizontal, vertical andoblique meridia of 45º and 135º. RESULTS. Binocular summation ratios (binocular sensitivity/ 'best' monocularsensitivity) were calculated for all the eccentricities. In the normal group,the mean binocular summation ratio for the fovea and the peripheral fieldwas not significantly different. In the amblyopic group, subjects showed noor minimal binocular summation in the foveal region but reached normal ratiosin the periphery. DISCUSSION. Results are discussed in terms of tolerance to interocularsensitivity differences in the periphery and selective losses in corticalcells. [ABSTRACT FROM AUTHOR]