The 401 on Strabismus
Strabismus is classified in three ways: the direction the eyes turn, frequency (constant or intermittent), and if it's the same eye (unilateral) or different eye (alternating). Below are the various directions an eye can turn and their respective names.
- Esotropia is when one or both eyes turn inward.
- Exotropia is when one or both eyes turn outward.
- Hypotropia is when one or both eyes turn downward.
- Hypertropia is when one or both eyes look upward.
The two most common types of strabismus include accommodative esotropia and intermittent exotropia. The former occurs with farsightedness due to extra focusing that causes the eyes to turn inward, and the latter is an inability to coordinate both eyes together, causing them to point beyond the object viewed.
- Those with accommodative esotropia complain of double vision, will tilt or turn their head to see better, and close or cover one eye when looking at things close up.
- Those with intermittent exotropia may develop headaches, have difficulty reading and eye strain, or close one eye when viewing objects at a distance or in bright light.
It is important to have tests performed if strabismus is suspected, especially if the person affected is a child. Typically, strabismus appears by age three but can happen later in life as well. Visual maturation happens by age eight, so it's important to be treated as early as possible because, unlike some conditions, strabismus cannot be outgrown and will get progressively worse.