Watzke-Allen slit beam test in macular holes confirmed by optical coherence tomography

Objective: To examine the role, validity, and interpretation of Watzke-Alle n slit beam testing in patients with idiopathic senile macular holes. Methods: Thirty-seven consecutive patients with 40 full-thickness macular h oles, confirmed on optical coherence tomography, were prospectively recruit ed. The Watzke-Allen slit beam test was used centrally and on the rim of th e macular hole in both vertical and horizontal orientations. Results: In 24 eyes, the beam was reported as thinned in both vertical and horizontal orientations when placed directly over the center of the macular hole. In 9 eyes, the Watzke-Allen slit was reported as broken in both vert ical and horizontal orientations. In 6 eyes, the beam was reported as broke n in one orientation and thinned in the other. In 1 eye, the beam was repor ted as kinked but not thinned or broken. When the beam was placed on the ed ge of the macular hole, all patients reported a displacement or bowing of t he beam away from the center of the hole. Conclusions: These findings confirm tangential traction of photoreceptors f rom a central foveal dehiscence as the causative mechanism in the developme nt of the majority of macular holes. Careful interpretation of the Watzke-A llen sign may offer a technique for preoperatively determining visual progn osis.