Strabismus, commonly known as crossed eyes, is a condition where the eyes do not align properly when looking at an object. This misalignment occurs because the six muscles surrounding each eye, which control eye movement, are not working together effectively to keep both eyes centered. While often associated with childhood, strabismus can persist into adulthood or develop later in life due to various factors, including stroke, trauma, or thyroid disease. Surgical correction aims to adjust the tension of these extraocular muscles to achieve proper alignment and function.
Primary Goals of Adult Strabismus Correction
The decision to pursue strabismus surgery in an adult is generally driven by two distinct, yet often interconnected, primary objectives. One major goal is to achieve cosmetic improvement, which involves physically straightening the eye so that the misalignment is either eliminated or significantly reduced. This visual correction can have a substantial positive impact on a patient’s self-perception and social interactions.
The second objective is functional improvement, primarily focused on eliminating or reducing double vision, known as diplopia. When the eyes are misaligned, they send two different images to the brain, which the adult visual system may not be able to suppress, leading to bothersome symptoms. Successful surgery can allow the eyes to work together, restoring binocular vision. In cases where diplopia cannot be fully eliminated, the surgery aims to reduce the misalignment to a small enough angle that it can be managed with prism glasses.
Measuring Surgical Success Rates
The success of strabismus surgery in adults is assessed based on whether the procedure meets the predetermined cosmetic and functional goals, often measured by the final angle of eye alignment. Many studies report a high rate of anatomical success, with satisfactory alignment achieved in approximately 70% to 90% of adult patients after a single procedure. Satisfactory alignment is typically defined as a residual deviation of less than 10 prism diopters, which is a small enough misalignment to be aesthetically acceptable and often functionally manageable.
It is important to understand that successful alignment does not always mean perfect alignment, but rather an outcome that resolves symptoms and satisfies the patient. For patients experiencing diplopia, functional success is measured by the elimination of double vision in the primary gaze position, or the ability to fuse images with minimal optical aids like prism glasses. Patients whose strabismus is due to underlying neurological issues or restrictive eye conditions, such as thyroid eye disease, may fall on the lower end of the success range due to the complexity of their condition.
A significant majority of patients, often exceeding 85%, report being satisfied or very satisfied with the outcome, highlighting the positive effect of the surgery on their quality of life. Surgeons often use adjustable sutures, where the eye muscle can be fine-tuned hours after the initial operation while the patient is awake. This technique is particularly helpful for complex or re-operative cases, contributing to the high reported success rates.
Recovery and Expected Post-Surgical Experience
The recovery period following adult strabismus surgery is generally straightforward, with most patients noticing an immediate change in eye position. The procedure is typically performed on an outpatient basis, allowing the patient to return home the same day. Patients should expect the eye to be noticeably red for several weeks, as the redness is a normal reaction to the manipulation of the eye muscles.
During the first week, it is common to experience moderate discomfort, often described as a scratchy or gritty sensation, and mild pain that can usually be managed with over-the-counter pain relievers. Swelling and bruising around the eye can also occur but typically begins to subside significantly within the first few days. Post-operative instructions usually include using antibiotic and anti-inflammatory eye drops for a prescribed period to prevent infection and manage inflammation.
Temporary double vision may occur immediately after surgery as the brain adjusts to the eyes’ new alignment, but this often resolves as the muscles heal. Most adults are able to return to desk work or light activities within one week. Activities that could introduce infection, such as swimming, are restricted for about four weeks, and contact sports are prohibited for up to six weeks to allow the eye muscles to fully heal without trauma.
Durability and Need for Follow-Up Procedures
The longevity of the surgical result is a common concern, as the eye muscles may gradually shift or “drift” back toward the original misaligned position over time. This tendency for the eye to regress means that the initial successful alignment may not always be permanent. The risk of the eyes returning to a noticeable deviation is influenced by the original cause of the strabismus and the size of the initial misalignment.
Because of this potential for drift, a secondary or enhancement procedure is sometimes necessary to fine-tune or maintain the alignment. The rate of reoperation in adults is generally reported to be between 8.5% and 10.13% within the first one to five years following the initial surgery. This rate tends to be slightly higher for more complex cases, such as those involving vertical misalignment or patients who have had previous strabismus surgeries.
While the majority of patients achieve a durable result after one surgery, the possibility of requiring a follow-up procedure is discussed during the initial consultation. The need for a second surgery does not indicate a failure of the first, but rather reflects the dynamic nature of eye muscle balance and the body’s healing response. Even when a second surgery is required, the overall long-term success rate for achieving a stable and satisfactory result remains high.