Evaluation of the Contrast Sensitivity Function in Patients with Intermittent Exotropia

Abstract

Normal individuals when exposed to a bright light will partially close both eyes and complain of photophobia while patients with an intermittent exotropia will, under the same conditions, close one eye more, namely the habitually deviating eye. The reason for this distinctive behaviour remains unexplained. The purpose of this study was to evaluate the contrast sensitivity function in intermittent exotropes in order to examine whether an impaired contrast sensitivity could help us understand the mechanisms underlying this anomaly. Our results showed that the habitually deviating eye of our intermittent exotropes had a reduced contrast sensitivity when compared to the fellow eye or to the contrast sensitivity measured in normals.

• exotropia
• contrast sensitivity function