Krembil Neuroscience Centre (KNC)
Strabismus and Ocular Motility
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Our Adult Strabismus and Ocular Motility Clinic represents the first clinic of it's kind in Canada. Patients with abnormalities of the extraocular muscles are assessed and treated with numerous modalities such as surgery and botulinum toxin. This clinic works in close conjunction with our Neuro-Ophthalmology Unit.
What is Strabismus?
Strabismus is the medical term for eyes that are not straight. An eye can turn in either the horizontal or vertical direction. Thus, there are different possible misdirections:
- If the eye turns inward it is often called a “crossed eye” and the medical term for this is “esotropia”.
- If the eye turns outward it is sometimes called a “wall-eye” and the medical term for this is “exotropia”.
- If one eye is higher than the other eye the medical term is “hypertropia”.
- An eye can drift at an oblique angle such that it is misaligned in both the horizontal and vertical directions at the same time.
Causes of Strabismus:
An adult may have strabismus that has persisted from the time he or she was a child, and it either was not successfully treated in childhood or else has recurred after being in a satisfactory state for a period of time. However, strabismus in adults can arise from many
other conditions, including:
- Loss of vision in one eye, as a result of diseases in the eyes such as cataracts, glaucoma, or retina abnormalities
- Trauma to the eye or the eye socket, causing damage to the muscles of the eye or the nerves that send messages to move the eye muscles
- Neurologic disorders, such as strokes and head trauma that affect the signals from the brain to the eye muscles
- Other medical conditions such as diabetes or thyroid disease in which the muscles ornerves that move the eyes do not function properly.
Treatment of Strabismus:
Depending on the type of strabismus and its cause, several options are available:
- No intervention at all! There are some conditions that either improve on their own or do not cause enough difficulty to justify therapy.
- Glasses: Correcting vision with glasses can lead to improved alignment and reduced symptoms in some cases, just as seen in children.
- Prisms: These are optical devices that can be pasted onto glasses or ground into glasses to help move the images seen by the two eyes closer to each other, allowing single vision.
- Eye exercises: Some forms of adult strabismus can be helped by exercises for the focussing of the eye muscles.
- Botox: Injections of eye muscles with Botox, which relaxes overacting muscles, can realign the eyes in some cases where the angle of misalignment is not excessive.
- Surgery: Eye muscle surgery can be performed on any of the eye muscles to restore normal alignment
- Patching or eye occlusion: In cases of double vision or eyestrain where surgery or other interventions are not possible, patching or some other occlusive device (such as a frosted lens) may be the only means to provide visual comfort.


