Discordant pursuit asymmetry and esotropia in monozygous twins.
OBJECTIVE
To report the relationship between infantile esotropia and asymmetry of monocular pursuit tracking.


METHODS
Observational family case series.


METHODS
A twin pair discordant for infantile esotropia was confirmed by DNA analysis to be monozygous at 99.95% probability. Digitally sampled electro-oculographic recordings of monocular horizontal pursuit eye movements were performed for the twins and their orthophoric father.


RESULTS
Mean directional asymmetry for right and left eyes was 31% and 5% for the esotropic twin, 10% and 8% for the orthophoric twin, and 5% and 6% for the father. The asymmetry was statistically significant only for the deviating right eye of the esotropic twin (P = 0.0217).


CONCLUSIONS
In this family, monocular pursuit asymmetry is probably not a heritable predisposition to infantile esotropia, but a consequence of early strabismus. Discordance of infantile esotropia and pursuit asymmetry in monozygous twins implicates environmental in addition to genetic causes.
Sharma
Pradeep
P
Department of Ophthalmology, University of California, Los Angeles, USA.
Rosenbaum
Arthur L
AL
Vives
Terre
T
Grody
Wayne W
WW
Demer
Joseph L
JL
D004247:DNA / Q000032:analysis; D004200:Diseases in Twins; D004585:Electrooculography; D004948:Esotropia / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007223:Infant; D015835:Ocular Motility Disorders / Q000235:genetics* / Q000503:physiopathology; D011698:Pursuit, Smooth / Q000502:physiology; D014430:Twins, Monozygotic / Q000235:genetics*; D015348:Vision, Binocular
D004247:DNA