A squint, medically known as strabismus, is a condition where the eyes do not align properly and point in different directions. One eye may look straight while the other turns inward, outward, upward, or downward. Strabismus can often be corrected or significantly improved through various treatment options. Successful correction depends on the underlying cause and the age at which treatment begins. Early diagnosis and intervention are extremely important for preventing long-term visual impairment.
Understanding Misalignment and Associated Risks
Correction is necessary primarily to prevent serious visual complications, not just for cosmetic reasons. When the eyes are misaligned, they send two different images to the brain. To avoid seeing double, the brain of a young child often suppresses, or ignores, the image from the misaligned eye.
This suppression leads to amblyopia, a permanent loss of vision in the affected eye if untreated. If strabismus develops in adulthood, the brain is less able to ignore the disparate images, often resulting in diplopia, or double vision. Misalignment can also cause poor three-dimensional (3D) vision, eye strain, and headaches.
Strabismus is classified by the direction of the eye turn: esotropia (inward), exotropia (outward), hypertropia (upward), and hypotropia (downward). The misalignment can be constant or intermittent. It may be present from birth or acquired later due to factors like refractive errors, muscle dysfunction, or neurological issues.
Non-Invasive Correction Strategies
For many patients, especially children, non-invasive methods are the first line of treatment and can often be sufficient for correction.
Prescription Eyewear
Prescription eyewear is highly effective when misalignment is caused by an uncorrected refractive error, known as accommodative esotropia. The extra focusing effort required to see clearly triggers an inward turn. Appropriate glasses reduce this focusing demand, which can resolve the squint entirely.
Patching (Occlusion Therapy)
Patching is a primary treatment used to address amblyopia resulting from the squint. This method involves covering the stronger eye for a specific number of hours each day. This forces the brain to use and strengthen the visual pathways of the misaligned eye, improving vision in the weaker eye.
Vision Therapy
Vision therapy, also known as orthoptics, involves a tailored program of exercises and visual activities. These exercises are designed to improve the coordination and focusing abilities of the eyes. This is useful for intermittent squints and issues like convergence insufficiency, where the eyes struggle to turn inward for near objects.
Botox Injections
Botox injections offer a temporary, non-surgical solution for certain cases of strabismus. Botulinum toxin is injected directly into a targeted, overactive eye muscle to temporarily weaken it. This relaxation allows the opposing muscle to achieve better alignment. The effect typically lasts for three to six months and is often used before considering surgery.
Surgical Treatment and Post-Operative Care
Eye muscle surgery is often the definitive treatment when non-invasive methods fail or for severe, constant deviations. The procedure adjusts the length or position of the six extraocular muscles that control eye movement. Surgery is generally performed on an outpatient basis under general anesthesia, though adults may sometimes receive local anesthesia with sedation.
The two main surgical techniques are recession and resection. Recession is a weakening procedure where the muscle is detached and reattached further back, reducing its pulling force. Resection is a strengthening procedure where a segment of the muscle is removed, effectively shortening it before reattaching it to its original insertion point. Both procedures are performed through a small incision in the conjunctiva, the clear membrane covering the white of the eye.
The timing of surgery is individualized, often occurring after non-surgical options have been exhausted, but sometimes performed early for severe congenital cases. Following the procedure, patients typically require a few days to weeks of rest. It is normal for the eyes to appear red and feel scratchy or sore for several weeks or even months. Patients are advised to avoid swimming for about two weeks to prevent infection.
While strabismus surgery is highly successful in achieving alignment, a small percentage of patients may require a second procedure, especially in complex cases. The surgery aims to improve both cosmetic appearance and functional vision, including depth perception.