[Time-course of interocular alignment in arteficially esotropic cats].

Strabismus induced by eye-muscle surgery is a widely accepted experimental model of discordant binocular vision. Up to now, no attention was paid to the progress of strabismus in the postsurgical period, although, the grade of the developing strabismus is strongly influenced by the loss of binocularity in the visual system. Following lateral rectus laminotomy of 2-week-old kittens, the Hirschberg method and prisms were used to assess interocular alignment. The angle of deviation was measured weekly. During the first postoperative weeks, cats fixated still alternally, while by the end of the second postnatal month, when compared to healthy controls, operated cats were unable to align their eyes parallelly. They also showed persistent esotropy (+35 +/- 7 delta) that developed with a characteristic time-course. The interocular misalignment in artificially strabismic kittens develop gradually, and does not simply appear after the operation. The nature of this pathological process resembles the normal development of eye-movements in kittens, as well as in primate infants. Therefore, the surgery for strabismus in experimental animals at the earliest time point during the sensitive period are recommended, in order to provide ample time-window window for the effective development of the "strabismic visual system".