At Scheie Eye Institute, neuro-ophthalmologists are experts at treating adult strabismus. The pediatric ophthalmologists at Children's Hospital of Philadelphia combine the expertise of ophthalmology, neurology and pediatric ophthalmology to treat strabismus in children.
What is strabismus?
Strabismus is the medical term for misaligned eyes -- a condition that occurs in three to five percent of the population. The eyes may turn inward (crossed, aka esotropia), outward (splayed, aka exotropia) or be vertically misaligned (hypertropia). In some cases, each eye may alternate between looking straight ahead and turning. As a result, the eyes do not work together. Each sees a different image, rather than the normal single fused image.
Strabismus can occur at anytime -- infancy, early childhood or adulthood. In some adults it may be a worsening of a childhood misalignment and may result in double vision. Children are rarely afflicted with strabismus-related double vision because their brains are able to process the image from one eye while suppressing the vision in the other.
Some individuals use the term "lazy eye" to refer to strabismus, but this
latter term is also used to refer to amblyopia.
Causes of Strabismus
The most common causes of strabismus in adults:
- Childhood history of strabismus (with or without previous surgery)
- Orbital disease such as thyroid eye disease
- Previous stroke or previous neurosurgical procedure
- Head trauma
- Diseases that affect the nerves, such as multiple sclerosis
- Poor vision in one eye
Symptoms of Strabismus
The main symptom of strabismus is a misaligned or turned eye, although significant misalignment may be present without a visible difference in the position of the two eyes.
Depending upon their age at the onset of the disease, people with strabismus may or may not experience double vision (diplopia), but adults frequently experience this symptom.
Children below the ages of six or seven usually do not develop double vision although they may sometimes appear to be squinting. A child's brain has the unique ability to suppress the image in one eye; essentially viewing the world through one eye at any given time. In many cases they begin to favor one eye, in these instances the other unused eye can develop a condition known as strabismic amblyopia.
The ability to suppress the vision in one eye is maintained for life. However, people who suppress the vision in one eye do not develop true depth perception (stereopis). Most people function well in life without depth perception because they learn to use other visual cues to compensate for their lack of stereopsis.
Patients with strabismus may experience symptoms that seem vague including trouble focusing, eyestrain, images jumping, difficulty tracking on a page, or loss of peripheral vision.