What does exotropia mean?
Exotropia is a type of strabismus, or eye misalignment, in which one or both eyes turn outward, away from the nose. It contrasts with esotropia, the inward-turning misalignment commonly known as being cross-eyed. Exotropia may be present constantly or intermittently, often becoming more apparent with fatigue, distance viewing, or bright light, and it ranges from mild and cosmetic to severe enough to impair binocular vision and depth perception. Causes include refractive errors, weak or imbalanced eye muscles, and impaired vision in one eye. Treatment depends on severity and may involve corrective lenses, vision therapy, patching, botulinum toxin injections, or surgery on the extraocular muscles. Derived from Greek roots meaning 'an outward turning,' the term is used almost exclusively in medical settings, where clinicians distinguish subtypes such as intermittent, congenital, and sensory exotropia.
nounA form of strabismus in which one or both eyes deviate outward, away from the nose. It is the opposite of esotropia, in which the eye turns inward.
- A strabismus in which one or both eyes turn outward, away from the midline of the face.
"The ophthalmologist diagnosed intermittent exotropia after noticing that her right eye drifted outward when she was tired."
"Intermittent exotropia often becomes more noticeable when a child is daydreaming or exposed to bright sunlight."
"After patching therapy failed to correct his exotropia, the surgeons recommended strabismus surgery to realign the eye muscles."
Rarely pluralized; usually treated as an uncountable condition, though 'exotropias' can appear when discussing distinct clinical types.
"The clinic treats various exotropias, from congenital to sensory forms."
From the Greek for 'a turning outward,' exotropia is the clinical name for what was once colloquially called 'wall-eyed' — and it's literally the mirror image of cross-eye.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of exotropia
The word exotropia derives from New Latin, combining the Greek prefix 'exo-' meaning 'outward' with '-tropia', from Greek 'tropē' meaning 'turn'. It was coined as the precise opposite of 'esotropia', which uses the prefix 'eso-' meaning 'inward'. Both terms entered English medical vocabulary in the nineteenth century as ophthalmology developed a systematic terminology for eye-muscle disorders. They share the root 'tropē' with words such as 'tropism' and 'heliotrope'.
How exotropia is actually used
Strictly a medical and ophthalmological term, used in clinical and formal contexts; lay speakers are more likely to say 'walleyed' or 'an eye that drifts outward.' The adjective form 'exotropic' is common in medical writing.
Easily confused with exotropia
Esotropia is the inward turning of an eye toward the nose, whereas exotropia is the outward turning away from it.