Friedburg D
Klin Monbl Augenheilkd. 1981 Feb;178(2):85-8. doi: 10.1055/s-2008-1055304.
Thirty-nine patients with convergent microstrabismus and 24 patients with central organic scotoma underwent measurements of stereo acuity. Stereopsis at distance was measured by means of a polarization haploscope using "plane-tests" and random dot tests respectively. For near stereopsis were used commercially available tests (Titmus Test, TNO-Test). Organic scotomata can be divided into "circumscribed central scotomata" and "sievelike scotomata", the latter leading to poorer performance in random dot tests. Large plane tests yielded better results than small ones. In microstrabism we found stereo acuities similar to those of patients with "sievelike scotoma". The results support the theory of displacement of fusion within Panum's area in microstrabismus leading to decreased local stereopsis due to decreased concentration of stereo units at the border of Panum's area.