It has been estimated that up to 4% of the adult population has strabismus, and strabismus surgery is commonly performed on Medicare-aged patients. Childhood strabismus may persist into or recur in adult life. Adults may also develop new-onset strabismus as a result of such varied conditions as microvascular cranial neuropathies, trauma, thyroid-related ophthalmopathy, cerebrovascular disease, or as a consequence of previous ocular or orbital surgery such as a scleral buckling procedure.
The clinical presentation of strabismus in adults can vary from an asymptomatic intermittent or constant deviation to symptomatic diplopia, asthenopia, and a compensatory head posture. Despite significant signs and symptoms, surgical treatment of strabismus is often delayed. One study has reported that almost half of adult patients delayed surgical treatment for a year or more, with an average delay of 19.9 years (range, 1 to 72 years) between the onset of strabismus and the time of surgery. Often the reason for delaying surgical intervention was misinformation about the success of strabismus surgery in adults.
The most common systemic conditions associated with new-onset strabismus in adults are microvascular diseases such as diabetes mellitus and hypertension. Abducens palsy is the most common cause of acquired cranial neuropathy in adults. Sequential cranial nerve palsies caused by microvascular diseases have been reported. Examples of other medical conditions that can be associated with strabismus in adult patients include thyroid disease, myasthenia gravis, giant cell arteritis, Parkinson disease, and cerebrovascular disease.