Adult strabismus is a condition where the eyes are misaligned, pointing in different directions instead of working together to focus on the same object. It affects adults who either developed the condition in childhood or acquired it later in life due to a medical event like a stroke, nerve damage, or thyroid disease. Unlike children, whose brains can sometimes suppress the image from the misaligned eye, adults with strabismus almost always experience double vision because their brains have already learned to process images from both eyes simultaneously.
Types of Eye Misalignment
Strabismus is classified by the direction the misaligned eye drifts. When one eye turns inward toward the nose, it’s called esotropia. When it turns outward, it’s exotropia. Vertical misalignment also occurs: one eye sitting higher than the other is a hypertropia, and one sitting lower is a hypotropia. Some people have a combination of horizontal and vertical misalignment.
The misalignment can also be constant or intermittent, and it may change depending on which direction you’re looking. When the degree of misalignment shifts with gaze direction, it’s called incomitant strabismus. Most adult strabismus falls into this category, which has important implications for treatment.
What Causes It in Adults
Some adults with strabismus have had the condition since childhood. It may have appeared early in life, corrected itself during development, and then resurfaced with age. As the eye muscles weaken over time, a previously controlled alignment problem can “decompensate,” meaning the brain and muscles can no longer maintain the correction they managed for years.
New-onset strabismus in adults usually traces back to a specific medical cause. Circulation problems from diabetes, high blood pressure, or mini-strokes can impair blood flow to the eye muscles or the nerves that control them. Damage to the cranial nerves (the third, fourth, or sixth) from poor blood supply, head injuries, or pressure from a growth is a common trigger. Thyroid disease can cause strabismus even when thyroid hormone levels are well controlled, because inflammation and swelling in the eye socket tissues restrict normal movement. Brain tumors and direct trauma to the eye or orbit are less common but serious causes.
How It Feels and What You Notice
The most recognizable sign is eyes that visibly point in different directions, but the sensory symptoms are often more disruptive to daily life. Double vision is the hallmark complaint. You may see two overlapping or side-by-side images of a single object, making reading, driving, and navigating stairs difficult or unsafe. Blurry vision and a loss of depth perception are also common, affecting tasks like pouring a drink or judging distances while walking.
Many adults describe a pulling or tugging sensation around the eye, or a general weakness in the area. To compensate for the misalignment, you might find yourself tilting or turning your head into an unusual position to see clearly. This head posture can become habitual and lead to neck and shoulder strain over time.
How It’s Diagnosed
An eye doctor performs a sensorimotor examination that measures both the direction and the degree of misalignment. The standard tool is a prism and alternate cover test: you focus on a target while the doctor alternately covers each eye and holds prisms of increasing strength in front of the misaligned eye until the shift is neutralized. This gives a precise measurement in prism diopters.
If one eye has significantly reduced vision, that test can be misleading because the weaker eye may not fixate properly. In those cases, a different approach uses a small light reflected off the cornea to estimate alignment. The misalignment is typically measured while the better-seeing eye is focused on a target, since that angle is the one that matters most for planning any correction.
Prism Glasses: A Nonsurgical Option
For small degrees of misalignment, prism lenses built into your glasses can redirect light so that both eyes receive the image in the same spot. This can relieve double vision, reduce visual confusion, and restore some depth perception. The benefit only lasts while you’re wearing the glasses, though. Prisms compensate for the misalignment but do not correct it.
Prism glasses have real limitations. If the misalignment is large, the lenses become thick and optically distorting. More importantly, because most adult strabismus is incomitant (the misalignment changes depending on where you look), a fixed prism correction only works for one gaze direction. You might see clearly when looking straight ahead but still have double vision when glancing to the side or down at a book. For these reasons, prisms work best as a temporary solution or for people with mild, stable misalignment.
Botulinum Toxin Injections
Injecting a small amount of botulinum toxin into an overacting eye muscle can temporarily weaken it, allowing the opposing muscle to pull the eye back toward alignment. The toxin’s direct effect wears off within about three months, but in some cases the improved alignment persists long after the drug is gone. When the injection overcorrects the alignment (pushing the eye too far the other direction), that induced shift gradually resolves over six to twelve weeks.
This approach is most commonly used for horizontal misalignment that isn’t caused by muscle restriction or paralysis. Success rates with a single injection tend to be lower in adults than in children who receive injections in both eyes. Botulinum toxin injections can serve as a standalone treatment for smaller deviations or as a bridge while waiting for a more permanent surgical correction.
Strabismus Surgery
Surgery is the most common treatment for significant adult strabismus. The procedure repositions one or more of the six tiny muscles attached to the outside of each eyeball, tightening some or loosening others to bring the eyes into alignment. It’s performed under general anesthesia, and a technique called adjustable sutures gives the surgeon a meaningful advantage in adults: the muscle is secured with a knot that can be modified after you wake up. While you’re alert and able to report what you see, the surgeon fine-tunes the muscle position, either immediately in the recovery area or in a follow-up visit within the first week. This two-stage approach offers greater precision and can reduce the need for repeat operations.
Success rates vary by the type of strabismus. Esotropia (inward turning) responds best, with about an 80% success rate for achieving satisfactory alignment. Vertical strabismus is close behind at roughly 78%. Exotropia (outward turning) and combined types are harder to correct, with success rates around 57% to 58%. Overall, about 18% of patients need a second surgery, typically around 19 months after the first.
What Recovery Looks Like
Most people need a few days to a couple of weeks off from work and daily activities. Your eyes will likely be red and feel sore or scratchy for several weeks as the surface heals. Driving is off the table for one to two weeks. Once you’re fully recovered, which generally takes a few weeks total, you can return to all your usual activities without restrictions.
The Psychological Side
Strabismus in adults carries a real psychosocial burden that often goes unmentioned. Visible eye misalignment affects how people perceive eye contact, and many adults with strabismus report heightened self-consciousness in social and professional situations. Research using validated self-consciousness surveys has shown that adults experience measurable increases in social anxiety and public self-consciousness related to their condition.
Corrective surgery appears to help on this front as well. A study evaluating patients before and after strabismus surgery found significant improvement in both social anxiety scores and public self-consciousness scores following the procedure. The strongest psychological benefits were seen in patients with esotropia and in those who were college-educated or in long-term relationships. Private self-consciousness (how you reflect on yourself internally) also trended toward improvement, though the change was smaller. These findings suggest that the benefits of treatment extend well beyond sharper vision and straighter-looking eyes, reaching into how comfortable people feel in their own skin around others.