The efficacy of muscular exercise in increasing the strength of the skeletal muscles is so apparent to physiologists and to the laity alike that by a fallacious analogy the idea has an inherent appeal to almost all patients when it is applied to the problems of ocular dysfunction. The deceptive simplicity of this idea has permitted orthoptic training to assume a place in ocular therapeutics almost as secure as the ophthalmologic panaceas—yellow mercuric oxide and boric acid—substances which are regarded with superstitious reverence as "something good for the eyes." It is hardly necessary to point out that wrong diagnosis, poor refraction, vertical muscular imbalance and aniseikonia1 are frequently responsible for the failure to obtain the relief from symptoms for which orthoptic training is so glibly prescribed.
We agree with Hofmann and Bielschowsky2 that the limits of the fusion movements are not rigid and that their amplitudes may
HICKS AM, HOSFORD GN. ORTHOPTIC TREATMENT OF SQUINT. Arch Ophthalmol. 1935;13(6):1026–1037. doi:10.1001/archopht.1935.00840060108010