Reversible mydriasis during strabismus surgery in children.

A study was made of changes in pupil diameter during strabismus surgery performed on 84 children aged from 1 to 12 years. Several factors influencing the appearance of reversible changes in pupil diameter during surgery were examined. The pupil diameters of both eyes were inspected during the course of the operation, and the reactions of manipulated eyes were compared to those of the non-manipulated eyes. Two types of general anesthesia were used, inhalation anesthesia and combined intravenous-inhalation anesthesia, depending upon the patient's body weight. Patient's age and sex, type of anesthesia, surgical procedure and the manipulated eye muscles were documented. The study demonstrated that mydriasis did not occur in patients operated under combined intravenous-inhalation anesthesia, while 74% of those operated solely under inhalation anesthesia developed mydriasis. This mydriasis only occurred during surgical manipulation of the eye muscles. The amount of traction on the other muscles, and the depth of anesthesia were not related to pupil diameter.