Modified Dynamometer.

RENEWED interest in ophthalmodynamometry during recent years has revealed difficulties in the actual technique which may be attributable, at least in part, to the dynamometer in common use, designed by Bailliart (1917). Many of these troubles have their origin in the lack of control over the instrument that is so frequently experienced. This is especially common when the operator is in the early stages of acquiring the technique. Another fault, less readily appreciated, is the ease and speed with which the dynamometer spring loses its "tone" and becomes inaccurate. This loss may be so marked that the instrument can no longer be relied upon to give the same reading when applied to the eye with identical pressures on two consecutive occasions. In an effort to improve this situation the author has modified Bailliart's dynamometer in the light of recent experience in the Dynamometry Clinic at the Manchester Royal Eye Hospital. The instrumentt (Fig. 1) is basically similar to the Bailliart model, but differs from it in certain respects.