Timing of surgery for infantile esotropia in humans: effects on cortical motion visual evoked responses.
OBJECTIVE
Infantile esotropia is associated with maldevelopment of cortical visual motion processing, manifested as directional asymmetry of motion visual evoked potentials (mVEPs). The purpose of this study was to determine whether early surgery at or before age 11 months could promote the development of cortical visual motion processing in human infants, compared with standard surgery at age 11 to 18 months.


METHODS
Sixteen children with a constant, infantile esotropia >or=30 prism diopters and onset before age 6 months were recruited prospectively. Eight of them underwent early surgery at <or=11 months of age, and eight underwent standard surgery at 11 to 18 months of age. Seven age-matched normal subjects served as the control. At 2 to 2.5 years of age, mVEPs were measured during monocular viewing of a grating that shifted between two positions with a lateral displacement of 90 degrees at 10 Hz. Nasotemporal mVEP asymmetry was assessed by an amplitude asymmetry index and by the presence of a significant interocular phase difference.


RESULTS
The mean asymmetry index and interocular phase difference in the early surgery group were comparable to that in age-matched control subjects, and they were significantly lower than those in the standard surgery group.


CONCLUSIONS
Early surgery for infantile esotropia promotes the development of cortical visual motion processing, whereas standard surgery is associated with abnormal mVEPs. The results provide additional evidence that early strabismus repair is beneficial for cortical development in human infants.
Gerth
Christina
C
Department of Ophthalmology and Vision Science, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada.
Mirabella
Giuseppe
G
Li
Xiaoqing
X
Wright
Thomas
T
Westall
Carol
C
Colpa
Linda
L
Wong
Agnes M F
AM
D005074:Evoked Potentials, Visual / Q000502:physiology*; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D020417:Nystagmus, Congenital / Q000503:physiopathology / Q000601:surgery*; D009801:Oculomotor Muscles / Q000601:surgery; D011446:Prospective Studies; D013710:Tendons / Q000601:surgery; D013997:Time Factors; D014793:Visual Cortex / Q000502:physiology*