Abstract
P 101
The Brückner reflex in induced esotropia
Christian Vieregge, Qasem Alhammouri, Michael Gräf
Klinik und Poliklinik für Augenheilkunde, Standort Gießen, Universitätsklinikum Gießen und Marburg GmbH, Gießen
Objective
The Brückner reflex allows for detection of amblyogenic factors. Brückner stated manifest strabismus to become apparent by the brighter fundus red reflex in the deviated eye. We evaluated the sensitivity to detect esotropia of 2° to 10° by this criterion.
Methods
Five well trained examiners performed the test on 5 emmetropic and 5 slightly myopic orthotropes at a distance of 1 m using a direct ophthalmoscope. By symmetrically placing base-in prisms in a trial frame in front of both eyes, esotropia of 2°-5°, 7,5° and 10° was simulated. In a sequence that was unpredictable for the examiner, the subjects were fixing the ophthalmoscope light either with the right eye or with the left eye. As a control condition, base-out prisms with a power of 0.5° were placed on front of both eyes of each subject which were easily compensated by fusional convergence. The examiner had to decide whether there was a difference in Brückner reflex between both eyes and if so, which pupil was brighter. The test was noted as positive, when the examiner considered the reflex different in both eyes.
Results
Esotropia of 2-5° was detected in 62 of 100 trials. In 48% of trials the brighter reflex was found in the deviated eye. Esotropia of 7.5° and 10°, resp., was detected in 85% and 93%, resp., with the brighter reflex in the deviated eye in 76% and 86%, resp., of the 100 trials. To achieve these detection rates very slight inter-ocular differences in the Brückner reflex had to be considered. The rate of false positive findings in the 300 control conditions was 36%.
Conclusions
The Brückner reflex does not allow for reliable detection of esotropia within the range of microstrabismus. To achieve a sensitivity of 62%, very discreet differences had to be considered pathologic. Therefore specificity was only 64%. The deviated eye was correctly identified in only 48%. Thus, the Brückner reflex is not sufficient as a single instrument in screening for strabismus.
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