Indoor and Outdoor Far Distance Measurements in Intermittent Exotropia

Abstract

Is bright sunlight a factor causing increased deviation or decreased fusion control in intermittent exotropia? Patients were tested at 60 feet indoors and retested at 60 feet outdoors. The data was analyzed to see whether the decrease in fusion control was due to the far distance fixation or the brightness of the surround. 82% of our patients had no change in fusion control from normal room illumination to bright sunlight. 82% of our patients had no change in far distance measurements from indoors to outdoors. 70% had neither a change in control nor a change in measurement. Indoor 20 feet distance measurements were also compared to the indoor 60 feet distance measurements. 79% of patients classified as divergence excess increased their deviation an average of 9^Δ from 20 feet to 60 feet.

• intermittent exotropia
• fusion control
• far distance
• sunlight