A PHOTOGRAPHIC METHOD OF MEASURING THE ANGLE OF SQUINT* BY

MEASUREMENT of the angle of deviation in squint is usually made either objectively or subjectively by means of the major amblyoscope. This instru-ment has the disadvantage that, although the fixation object is optically at infinity, the known proximity of the apparatus may stimulate convergence (see, for instance, Schapero and Levy, 1953). The readings vary from operator to operator, especially by the objective method, and may differ widely from the visual estimate made by a practised surgeon from observa-tion of the corneal reflex. An attempt has been made to avoid some of these difficulties by assessing the angle of squint by photographic means. This also provides a permanent record which may be compared with similar records obtained later. The method to be described, though more time-consuming than that using the synoptophore, requires a minimum of co-operation from the patients, in that they are simply required to fix a small light. It places on a quantitative basis the method employed in visual estimation of the angle by the position of th