How Optical Correction Tends to
Decrease 6° Esophoria in a Child
Assume binocular muscle test made before optical correction shows
6° Esophoria.
+1. Sph. = -1. Cyl. Ax. 180.
Next, locate faulty muscle by making a duction test, which shows how abduction of left eye is made to equal that of right eye, change being made quarterly with treatment lenses in accordance with following rule. Note as abduction is increased, esophoria is reduced.
Rule—prescribe a quarter diopter increased sphere for each degree of imbalance or 0.25 × 6 equals:
+1.50 added to optical correction.
1/1/19 (assumed date) prescribed treatment lenses equal:
+2.50 = -1. × 180°.