Esotropia was experimentally produced in three and exotropia in two rhesus macaque monkeys at different ages after birth. The animals were conditioned to respond behaviorally to Landolt rings of different sizes in order to determine visual acuity. After this task was mastered by the animals, complete tarsorrhaphy was performed on the fixating eye, and acuity measurements were resumed with the deviated eye. Strabismic amblyopia was present in two esotropic monkeys that had experimental onset of strabismus during the first week of life. In both animals the amblyopic eye showed recovery in acuity but had not reached the level of acuity of the sound eye by the time this report was written. Amblyopia was absent in the third esotropic animal, whose onset of surgical strabismus was at 15 months, and it was absent in the two exotropic monkeys, who could hold fixation with either eye.
von Noorden GK, Dowling JE. Experimental Amblyopia in MonkeysII. Behavioral Studies in Strabismic Amblyopia. Arch Ophthalmol. 1970;84(2):215-220. doi:10.1001/archopht.1970.00990040217015