DEPTH-PERCEPTION IN MONOCULARLY DEPRIVED CATS FOLLOWING PART-TIME REVERSE OCCLUSION

The behavioural effects of an early period of monocular deprivation ca n be extremely profound. However, it is possible to achieve a high deg ree of recovery, even to normal levels of visual acuity, by prompt imp osition of certain regimes of part-time reverse occlusion where the in itially non-deprived eye is occluded for only part of each day in orde r to allow a daily period of binocular visual exposure. In this paper we report on the depth perception of five monocularly deprived cats th at had recovered normal visual acuity in both eyes following impositio n of certain of the above occlusion regimes. Although three of the ani mals exhibited five- to sevenfold superiority of binocular over monocu lar depth thresholds, subsequent tests made on two of the animals reve aled that they were unable to make stereoscopic discriminations with r andom-dot stereograms. Despite the recovery of normal visual acuity in both eyes, we conclude that these animals recover at best only local stereopsis.