A New Classification of the Motor Anomalies of the Eye (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1897 Excerpt: ...accurate, for, owing to the fact that the visual lines tend to diverge when the gaze is directed Upward and to converge when they are directed downward, an exophoria otherwise eomitant will show an increase in the upper and a decrease in the lower portions of the field of fixation. (2) A deviation which remains constant or nearly so while the eyes are performing parallel movements is due, not to an anomaly of individual muscles, but to an anomaly of some one of the associated movements of the eyes. (3) A deviation which increases as the eyes are converged denotes a convergence-anomaly, and one which increases as the eyes are passing from convergence to parallelism a divergence-anomaly. Transformation of Non-comitant into Comitant Deviations. Non-comitancy in parallel movements might be remedied by restricting or increasing the action of the unaffected eye in the same sense as that in which the action of the affected eye is restricted or increased;. e. by converting the anomaly from one of Class I. into one of Class II. This is done in actual practice when, e. g. in a paralysis of the superior oblique of the right eye we tenotomize its associated antagonist, the inferior rectus of the other eye, thereby weakening the latter artificially in precisely the same sense and to the same extent that the right eye is weakened naturally. In nature a similar, though less perfect, result is commonly attained by the development of a spasm of the direct antagonist or of a pair of antagonistic muscles in the eye affected. Thus in a paralysis of the right externus, which produces a deviation confined to the right half of the field of fixation, is usually followed after a time by a spastic contraction of the right internus, which produces a deviation of the same character in...