TY - JOUR
T1 - Causing and curing infantile esotropia in primates
T2 - the role of decorrelated binocular input (an American Ophthalmological Society thesis).
AU - Tychsen, Lawrence
PY - 2007
Y1 - 2007
N2 - PURPOSE: Human infants at greatest risk for esotropia are those who suffer cerebral insults that could decorrelate signals from the 2 eyes during an early critical period of binocular, visuomotor development. The author reared normal infant monkeys, under conditions of binocular decorrelation, to determine if this alone was sufficient to cause esotropia and associated behavioral as well as neuroanatomic deficits. METHODS: Binocular decorrelation was imposed using prism-goggles for durations of 3 to 24 weeks (in 6 experimental, 2 control monkeys). Behavioral recordings were obtained, followed by neuroanatomic analysis of ocular dominance columns and binocular, horizontal connections in the striate visual cortex (area V1). RESULTS: Concomitant, constant esotropia developed in each monkey exposed to decorrelation for a duration of 12 to 24 weeks. The severity of ocular motor signs (esotropia-angle; dissociated vertical deviation; latent nystagmus; pursuit/optokinetic tracking asymmetry; fusional vergence deficits), and the loss of V1 binocular connections, increased as a function of decorrelation duration. Stereopsis was deficient and motion visual evoked potentials were asymmetric. Monkeys exposed to decorrelation for 3 weeks showed transient esotropia but regained normal visuomotor behaviors and binocular V1 connections. CONCLUSIONS: Binocular decorrelation is a sufficient cause of infantile esotropia when imposed during a critical period of visuomotor development. The systematic relationship between severity of visuomotor sign, and severity of V1 connectivity deficit, provides a neuroanatomic mechanism for several of these signs. Restoration of binocular fusion and V1 connections, after short durations of decorrelation, helps explain the benefits of early repair in human strabismus.
AB - PURPOSE: Human infants at greatest risk for esotropia are those who suffer cerebral insults that could decorrelate signals from the 2 eyes during an early critical period of binocular, visuomotor development. The author reared normal infant monkeys, under conditions of binocular decorrelation, to determine if this alone was sufficient to cause esotropia and associated behavioral as well as neuroanatomic deficits. METHODS: Binocular decorrelation was imposed using prism-goggles for durations of 3 to 24 weeks (in 6 experimental, 2 control monkeys). Behavioral recordings were obtained, followed by neuroanatomic analysis of ocular dominance columns and binocular, horizontal connections in the striate visual cortex (area V1). RESULTS: Concomitant, constant esotropia developed in each monkey exposed to decorrelation for a duration of 12 to 24 weeks. The severity of ocular motor signs (esotropia-angle; dissociated vertical deviation; latent nystagmus; pursuit/optokinetic tracking asymmetry; fusional vergence deficits), and the loss of V1 binocular connections, increased as a function of decorrelation duration. Stereopsis was deficient and motion visual evoked potentials were asymmetric. Monkeys exposed to decorrelation for 3 weeks showed transient esotropia but regained normal visuomotor behaviors and binocular V1 connections. CONCLUSIONS: Binocular decorrelation is a sufficient cause of infantile esotropia when imposed during a critical period of visuomotor development. The systematic relationship between severity of visuomotor sign, and severity of V1 connectivity deficit, provides a neuroanatomic mechanism for several of these signs. Restoration of binocular fusion and V1 connections, after short durations of decorrelation, helps explain the benefits of early repair in human strabismus.
UR - http://www.scopus.com/inward/record.url?scp=48649089131&partnerID=8YFLogxK
M3 - Article
C2 - 18427630
AN - SCOPUS:48649089131
SN - 0065-9533
VL - 105
SP - 564
EP - 593
JO - Transactions of the American Ophthalmological Society
JF - Transactions of the American Ophthalmological Society
ER -