At what age should patients with strabismus be operated on? This question is frequently propounded to all who are particularly interested in this phase of ophthalmology. The answer to it is not so simple as the questioner often thinks. He usually expects some concrete age to be set, but an intelligent opinion can be given only after consideration of many factors. I shall briefly review a few of the things one should know before arriving at a decision to operate.
A complete diagnosis of the motor anomaly is the first essential. Such a study should include an accurate measurement of the amount of the deviation at 20 feet (6 meters) and at 13 inches (33 cm.). For this determination I strongly urge the use of the screen and parallax test of Duane. The accuracy of this method has long been known, yet many still neglect to use it. The cruder