title: Motion detection in normal infants and young patients with infantile esotropia.
abstract: The purpose of this study was to investigate asymmetries in detection of horizontal motion in normal infants and children and in patients with infantile esotropia. Motion detection thresholds (% motion signal) were measured in 75 normal infants and in 36 eyes of 27 infants with infantile esotropia (ET), using a forced-choice preferential looking paradigm with random-dot patterns. Absolute motion detection sensitivity and asymmetries in sensitivity for nasalward (N) vs. temporalward (T) directions of motion were compared in normal and patient populations, ranging in age from 1 month to 5 years. In normal infants, N and T thresholds were equivalent under 2.5 months of age, whereas a superiority for monocular detection of N motion was observed between 3.5 and 6.5 months of age. The nasalward advantage gradually diminished to symmetrical T:N performance by 8 months of age, matching that of adults. No asymmetry was observed in 15 normal infants who performed the task binocularly, hence, the asymmetry was not a leftward/rightward bias. In the youngest infantile ET patients tested, at 5 months of age, a nasalward superiority in motion detection was observed and was equivalent to that of same-age normal infants. However, unlike normals, this asymmetry persists in older patients. This greater asymmetry in infantile ET represents worse detection of T than N motion. This is the first report of an asymmetry in motion detection in normal infants across a wide age range. Initially, motion detection is normal in infants with infantile esotropia. Cumulative abnormal binocular experience in these patients may disrupt motion mechanisms.
authors.affiliation: Department of Psychology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA. robosworth@ucsd.edu
authors.forename: Rain G
authors.initials: RG
authors.lastname: Bosworth
authors.forename: Eileen E
authors.initials: EE
authors.lastname: Birch
mesh_terms: D000375:Aging / Q000502:physiology; D002657:Child Development / Q000502:physiology; D002675:Child, Preschool; D004948:Esotropia / Q000503:physiopathology*; D006257:Head; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009039:Motion Perception / Q000502:physiology*; D009666:Nose; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D011930:Reaction Time; D012684:Sensory Thresholds; D015348:Vision, Binocular / Q000502:physiology; D015349:Vision, Monocular / Q000502:physiology