Distance alternate-letter suppression test for objective assessment of sensorial status in intermittent exotropia.
OBJECTIVE
To investigate the value of distance alternate-letter suppression testing in the objective assessment of fusional control of intermittent exotropia.


METHODS
A total of 71 consecutive patients with intermittent exotropia (study group) and 112 normal subjects (control group) underwent a series of measurements including distance alternate-letter suppression testing, Worth 4 Dot test at distance and near, and distance and near stereo acuity tests to see whether sensorial behavior differed in the study and control groups. The distance alternate-letter suppression test and distance stereo acuity tests were performed using the Mentor B-VAT II-SG Video Acuity Tester and Binocular Vision Testing System. The TNO test was used to measure near stereo acuity.


RESULTS
Seventeen patients with intermittent exotropia (24%) presented suppression with the distance alternate-letter suppression test, but none of the normal subjects (p<0.001, chi2 test). Only, three patients (4%) showed suppression on the Worth 4 Dot test at distance, and all had fusion on the Worth 4 Dot test near. Patients with intermittent exotropia had significantly diminished distance stereo acuity compared to normal subjects (p<0.001). Normal subjects and patients had good near stereo acuity (p>0.05). Patients with intermittent exotropia who had fusion with the distance alternate-letter suppression test had significantly better distance stereo acuity than patients who had suppression (p<0.001).


CONCLUSIONS
Distance alternate-letter suppression testing and distance stereo acuity tests may be useful as objective measures for assessing sensory loss in patients with intermittent exotropia.
Yildirim
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C
Department of Ophthalmology, Pamukkale University School of Medicine, Denizli, Turkey. yildirimc@hotmail.com
Altinsoy
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HI
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003867:Depth Perception / Q000502:physiology; D005099:Exotropia / Q000503:physiopathology*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D014787:Vision Tests; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*