Effects of enucleation of the nondeprived eye on stimulus deprivation amblyopia in monkeys.

The effects of enucleation of the nondeprived eye on the visual function of the deprived eye were studied in two rhesus monkeys reared with long-term lid suture. The lids of one eye of each monkey were surgically fused at the age of approximately 1 month. The lids were opened at ages 19 months and 22 months, and the nondeprived eyes were enucleated at age 57 months. Three measures of visual function (spatial modulation sensitivity, temporal modulation sensitivity, and increment-threshold spectral sensitivity) were determined for the nondeprived and deprived eyes before enucleation and for the deprived eyes during a 9-month period following enucleation. Neither the spatial nor temporal modulation sensitivity measurements showed significant recovery of visual function. The postenucleation spectral sensitivity data showed some recovery of sensitivity over the long wavelength region of the spectrum during the first 3 months, but there was no further recovery over the next 6 months. Therefore, the results of the experiments show that enucleation of the nondeprived eye of monkeys with severe stimulus deprivation amblyopia does not result in a significant functional improvement of the deprived eye.