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Torsional optokinetic nystagmus in strabismus
Author(s) -
PROUDLOCK FA,
FAROOQ SJ,
MCLEAN RJ,
GOTTLOB I
Publication year - 2008
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2008.4425.x
Subject(s) - optokinetic reflex , strabismus , nystagmus , monocular , audiology , medicine , eye movement , torsion (gastropod) , monocular vision , ophthalmology , optics , anatomy , physics
Purpose Torsional optokinetic Nystagmus (tOKN) in patients with strabismus since childhood has not been previously evaluated.The authors investigated the optokinetic response in horizontal, vertical and torsional directions in strabismus patients and in age‐matched normal volunteers. Methods Monocular torsional, horizontal and vertical eye movements were recorded in 16 subjects with childhood strabismus and 15 normal volunteers.Constant velocity horizontal (nasalward and temporalward) and vertical(upward and downward) OKN stimuli were used at 10°/s, 20°/s and 40°/s.Torsional(intorsion and extorsion)OKN stimuli were rotated at velocities of 40° and 400°/s. Results OKN responses from strabismus patients produced significant asymmetric responses in horizontal and vertical directions. The nasalward response was significantly greater than the temporalward and upward response was greater than downward. A significant high incidence of absent tOKN was present in both intorsion and extorsion. Eight of the 15 patients tested did not respond to any stimulus in either direction in their non‐dominant eye and 4 showed no response in their dominant eye. Conclusion Torsional OKN is dramatically affected in the presence of strabismus with a high incidence of no response. The possibility of a lack of development in the binocular cortical structures that respond to torsional motion could explain these findings.