1. Longitudinal Development of Ocular Misalignment in Nonhuman Primate Models for Strabismus
- Author
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Apoorva Karsolia, Emily Burns, Mythri Pullela, and Vallabh E. Das
- Subjects
Male ,medicine.medical_specialty ,infant development ,genetic structures ,nonhuman primate ,Cercopithecidae ,Sensory system ,050105 experimental psychology ,Pupil ,03 medical and health sciences ,0302 clinical medicine ,Ophthalmology ,medicine ,Animals ,0501 psychology and cognitive sciences ,Longitudinal Studies ,Strabismus ,Hirschberg test ,Visual Cortex ,Neurons ,Vision, Binocular ,Eye Movements, Strabismus, Amblyopia and Neuro-ophthalmology ,business.industry ,05 social sciences ,General Medicine ,prism-viewing ,Refractive Errors ,Macaca mulatta ,strabismus ,eye diseases ,Nonhuman primate ,Longitudinal development ,Disease Models, Animal ,binocular decorrelation ,Animals, Newborn ,Time course ,Female ,sense organs ,business ,030217 neurology & neurosurgery - Abstract
Purpose To investigate the longitudinal change in horizontal and vertical ocular alignment in normal and prism-reared infant monkeys during the critical developmental period. Methods Ocular alignment was measured using Hirschberg photographic methods in 6 infant monkeys reared under prism-viewing from day 1 after birth to 4 months, and 2 monkeys reared with normal visual experience. Photographs were acquired twice a week for the first 6 months of life and analyzed to identify pupil center and the first Purkinje image from which eye positions and strabismus angle were calculated. Results At 3 weeks after birth, prism monkeys presented with significant horizontal ocular misalignment. A gradual change in alignment was seen in all prism-reared monkeys stabilizing at approximately 11 weeks, at which time 5 monkeys were exotropic (mean, 16° XT; range, 13°-24°) and 1 monkey was esotropic (5° ET). A reduction in ocular misalignment was observed after exposure to normal visual environment at 16 weeks, but at 34 weeks of age, that is, 18 weeks after removal of prisms, prism-reared monkeys displayed a mean horizontal strabismus of 7° XT (range, 2° ET to 20° XT), which was still significantly different from normal monkeys. Conclusions Prism-rearing disrupts binocular fusion mechanisms, and horizontal and vertical strabismus is seen to develop as early as 3 weeks of age in monkey models, equivalent to approximately 3 months in humans. The time course of change in alignment overlaps with disruption in various visual sensory functions, suggesting a causal temporal link between sensory and motor mechanisms for alignment.
- Published
- 2020