Strabismus
Understanding Strabismus: Types and Symptoms
In children, strabismus often appears as a visible crossing or wandering of one or both eyes. You might notice that your child tilts their head to see better or closes one eye in bright light. They may also complain of double vision or have trouble judging distances when reaching for objects.
Adults with strabismus may experience sudden onset of eye misalignment after an injury, stroke, or other medical event. Some adults have had mild misalignment since childhood that becomes more noticeable or symptomatic over time. Double vision is more common in adults than children because the adult brain has a harder time suppressing the image from the misaligned eye.
Many infants look crossed because of a broad nasal bridge or epicanthal folds. This is called pseudostrabismus and the eyes are actually aligned. A simple light reflex test during the exam helps tell the difference.
Any constant eye turn after 3 to 4 months of age is not normal and should be evaluated. If you notice a white pupil in photos, very poor red reflex, or a new head tilt with the eye turn, seek prompt care.
Strabismus is classified by the direction the eye turns. Esotropia means the eye turns inward toward the nose, while exotropia describes an outward turn toward the ear. Hypertropia refers to an upward turn, and hypotropia indicates a downward turn.
- Constant strabismus is present all the time
- Intermittent strabismus appears only sometimes, such as when tired or sick
- Alternating strabismus switches between eyes
- Unilateral strabismus always affects the same eye
When your eyes do not work together as a team, your brain receives two different images. In young children, the brain often learns to ignore the image from the misaligned eye to avoid confusion. This suppression can lead to amblyopia, also known as lazy eye, where vision in the ignored eye fails to develop properly.
Depth perception relies on both eyes working together to judge distances accurately. People with strabismus may have difficulty with tasks like catching a ball, pouring liquid into a cup, or parking a car. The earlier we treat strabismus, the better the chance of preserving or restoring binocular vision and depth perception.
If sudden double vision occurs with any stroke warning sign, call emergency services. Certain symptoms signal that you need urgent evaluation by our eye doctor. Sudden onset of double vision in an adult can indicate a stroke, aneurysm, or other serious neurological problem. Rapid or painful eye movement along with misalignment may suggest an underlying infection or inflammation.
- Abrupt double vision that starts within hours or days
- Eye misalignment following a head injury or accident
- Severe headache or confusion along with crossed eyes
- Drooping eyelid or pupil size difference accompanying the misalignment
- Vision loss in one or both eyes
- Face droop, arm weakness, speech trouble, severe imbalance, or thunderclap headache
- White pupil in a child's photo along with an eye turn
- Severe, painful new droopy eyelid with a larger pupil
Risk Factors and Causes of Eye Misalignment
Strabismus often runs in families, suggesting a genetic component to the condition. If you or your partner had crossed eyes as a child, your children have a higher chance of developing strabismus. We recommend early vision screenings for children with a family history so we can detect and treat misalignment before it affects vision development.
Certain genetic syndromes that affect muscle function, nerve signaling, or brain development also increase the risk of eye misalignment. These include Down syndrome, cerebral palsy, and other conditions that impact muscle tone and coordination throughout the body. Congenital cranial dysinnervation disorders such as Duane syndrome and congenital fibrosis of the extraocular muscles can cause eye misalignment.
Several health problems can interfere with the nerves and muscles that control eye movement. Thyroid eye disease can cause swelling and restriction of the eye muscles, leading to vertical or horizontal misalignment. Diabetes may damage the nerves that control eye movement, resulting in sudden onset strabismus.
- Brain tumors or increased pressure inside the skull
- Stroke or transient ischemic attack
- Myasthenia gravis and other neuromuscular disorders
- Severe refractive errors like high farsightedness
- Cataracts or other vision problems that blur sight in one eye
- Prematurity and low birth weight
- Cranial nerve palsies involving the third, fourth, or sixth nerves
- Anisometropia and unequal visual input between the eyes
In infants and young children, strabismus often develops because the eye muscles or the brain pathways controlling them have not matured properly. Some babies are born with misalignment, while others develop it during the first few years of life as the visual system is still developing.
Adults typically develop strabismus due to injury, disease, or age-related changes in the eye muscles and nerves. A new misalignment in adulthood always warrants a thorough medical evaluation to rule out serious underlying conditions. The cause guides our treatment approach and helps predict outcomes. New vertical or torsional diplopia in adults requires careful neurologic and orbital evaluation to rule out nerve palsy or restrictive disease.
Diagnostic Tests and Evaluation
Our eye doctor will start by taking a detailed history about when you first noticed the misalignment and whether it is constant or comes and goes. We will ask about any symptoms like double vision, headaches, or difficulty with tasks that require depth perception. A review of your medical history and any family history of eye problems helps us understand potential causes.
A cycloplegic dilated refraction is essential in children and many adults to detect uncorrected farsightedness or anisometropia that can cause or worsen esotropia. A dilated exam also evaluates the retina and optic nerve for causes of reduced vision.
The physical examination includes checking how each eye moves in all directions and observing how your eyes work together. We will assess your vision in each eye separately and look for signs of amblyopia. A thorough evaluation of the front and back of your eyes helps us rule out other conditions that might contribute to misalignment.
We use several techniques to measure the exact amount and direction of eye misalignment. The cover test is a fundamental assessment where we cover one eye at a time while you look at a target, then observe how the eyes move when uncovered. This reveals which eye is misaligned and in what direction.
- Prism measurements quantify the angle of deviation in prism diopters
- Hirschberg test evaluates alignment by observing light reflections on the corneas
- Krimsky test uses prisms to center the corneal light reflexes
- Measurement in different gaze positions shows if the deviation changes with eye position
- Prism alternate cover test at distance and near to quantify deviation
- Measurement in the nine cardinal positions of gaze to detect incomitance
- Bielschowsky head tilt test for vertical deviations
- Double Maddox rod to assess torsion
- Forced duction and force generation testing when restriction or paresis is suspected
We perform tests to determine whether your eyes can work together and how well your brain fuses the images from both eyes. Stereopsis testing measures your depth perception using special images or patterns that can only be seen when both eyes cooperate. Worth 4-dot test helps us understand if you are suppressing vision in one eye or experiencing double vision.
Ocular motility testing checks the strength and coordination of each eye muscle by having you follow a moving target in different directions. We also assess convergence, which is the ability of your eyes to turn inward when looking at near objects. These tests help us design the most effective treatment plan for your specific type of strabismus. We may also use Bagolini striated lenses or a synoptophore to assess fusion and suppression.
The severity of strabismus depends on several factors beyond just the angle of deviation. We consider whether the misalignment is constant or intermittent, whether you have any ability to align your eyes on your own, and whether you have developed amblyopia or double vision. The impact on your daily activities and quality of life also influences our treatment recommendations.
Large angle deviations generally require more aggressive treatment, but even small misalignments can cause significant symptoms if they result in double vision. We also evaluate whether the deviation is stable or getting worse over time. All these factors help us determine the urgency and type of intervention you need.
Imaging or lab testing is ordered when the presentation suggests an acquired neurologic or orbital cause.
- Acute third nerve palsy, especially with a large pupil or pain: urgent vascular imaging
- Nonresolving or progressive sixth nerve palsy, multiple cranial neuropathies, or other neurologic signs: brain and orbital imaging
- Trauma with restricted eye movements or suspected orbital fracture: CT orbit
- Suspected thyroid eye disease with restriction or proptosis: thyroid evaluation and orbital imaging when indicated
- Fluctuating diplopia and ptosis: testing for myasthenia gravis
- New diplopia in adults over 50 with headache, scalp tenderness, or jaw claudication: urgent ESR and CRP to evaluate for giant cell arteritis
Vision Therapy for Strabismus
Vision therapy involves a series of customized exercises designed to improve eye coordination and strengthen the connection between your eyes and brain. These exercises challenge your visual system to develop better alignment and teamwork between the eyes. Some activities use special lenses, prisms, or filters to make your eyes work harder to fuse images.
Computer-based programs and hands-on activities help retrain the neural pathways that control eye movement and binocular vision. Over time, these exercises can reduce the amount of misalignment and improve your ability to maintain eye alignment and depth perception. Vision therapy works best when the brain still has the flexibility to form new connections and adapt to changes.
Vision therapy tends to work best for people with small to moderate intermittent strabismus who still have some ability to align their eyes. Convergence insufficiency, where the eyes struggle to turn inward for near work, often responds well to vision therapy exercises. Children and adults with good vision in both eyes and no significant amblyopia typically see better results than those with severe vision differences between eyes.
- Intermittent exotropia in selected patients for symptom control and improved control of the deviation, with limited effect on the angle
- Convergence insufficiency causing eye strain during reading
- Small residual misalignment after previous surgery
- Mild deviations in motivated patients willing to do home exercises
Orthoptic therapy is most effective for convergence insufficiency and decompensated phorias. It has limited benefit for constant tropias.
A vision therapy program usually includes weekly or biweekly sessions in our office combined with daily exercises at home. Each session lasts about 30 to 60 minutes and is supervised by a trained therapist who adjusts the difficulty based on your progress. You will work on activities that challenge eye teaming, focusing, and tracking skills.
Home exercises reinforce what you learn in office visits and might include using special targets, balance boards, or computer programs. The exercises become progressively more challenging as your skills improve. Consistency is key, so we work with you to develop a schedule that fits your daily routine and keeps you engaged with the therapy process. Therapy is typically delivered by an orthoptist or optometrist and coordinated with your ophthalmologist.
Most programs last 12 to 24 weeks. Symptom relief, such as reduced eye strain, may be noticed within a few weeks, but durable changes require consistent practice.
Best evidence supports office-based therapy with home practice for convergence insufficiency. Results for intermittent exotropia are mixed, with therapy aimed at symptom control and improved control rather than a lasting reduction in angle. Constant large-angle deviations rarely respond to therapy and usually require surgery.
Surgical and Medical Treatment Options
Strabismus surgery involves adjusting the position or tension of the muscles that control eye movement. The surgeon may strengthen a weak muscle by shortening it, or weaken an overactive muscle by repositioning its attachment point on the eyeball. Most procedures are performed on the outer surface of the eye and do not involve entering the eyeball itself.
The surgery is typically done under general anesthesia for children and may use local anesthesia with sedation for adults. We carefully calculate how much to adjust each muscle based on measurements taken during your examination. The goal is to align your eyes as closely as possible and restore binocular vision if your visual system is capable of it. In many adults, adjustable sutures allow fine tuning of alignment during a short adjustment session after surgery. Not all cases are candidates for adjustable sutures.
Risks include over or undercorrection, persistent or new diplopia, infection or scarring, slipped or lost muscle requiring urgent repair, rare scleral perforation, and anterior segment ischemia when multiple rectus muscles are operated on in older adults. Many patients need more than one surgery over time.
Your ophthalmologist or strabismus surgeon may recommend surgery when the misalignment is large, constant, and unlikely to improve with vision therapy alone. Very young children with constant esotropia often need surgery to give their developing visual system the best chance at learning binocular vision. Adults with sudden onset strabismus that does not resolve after treating the underlying cause may also need surgical intervention.
- Constant large angle deviations present since early childhood
- Strabismus that has not responded to glasses, patching, or vision therapy
- Misalignment causing severe double vision that glasses cannot correct
- Restrictive strabismus from scarring or thyroid eye disease
- Significant cosmetic concerns affecting social interactions and self-esteem
Some forms of strabismus, especially those related to uncorrected farsightedness, improve significantly with glasses alone. Accommodative esotropia occurs when the eyes cross while trying to focus up close, and the right prescription can often eliminate or reduce this type of misalignment. We may prescribe bifocal lenses if the crossing is worse at near than at distance. A cycloplegic refraction is used to determine the full hyperopic correction. High AC/A esotropia often benefits from bifocals for near tasks.
Prism lenses bend light before it enters your eye, which can help reduce or eliminate double vision without changing eye position. Small prisms can be incorporated into your regular glasses to make it easier for your brain to fuse the images from both eyes. While prisms do not cure strabismus, they can improve comfort and function in cases where the deviation is too small for surgery or as a temporary measure while planning other treatments. Fresnel press-on prisms are useful as a temporary option to trial prism strength or while planning surgery.
Botulinum toxin injections may be considered in specific cases as an alternative to traditional strabismus surgery. The injection temporarily weakens an overactive eye muscle, allowing the opposing muscle to pull the eye into better alignment. This approach can be useful for some types of acute strabismus or as a test to predict surgical results.
The effects typically last three to six months before the muscle function returns. While this treatment avoids incisions, it requires expertise in injection technique and is not appropriate for all types of strabismus. We discuss this option when it aligns with current evidence and might offer advantages over traditional surgery for your specific situation. Common temporary side effects include droopy eyelid, vertical deviation, dry eye from incomplete blink, and over or undercorrection; repeat injections may be needed.
In many cases, we recommend combining surgical correction with pre-operative or post-operative vision therapy. Surgery can align the eyes mechanically, but your brain still needs to learn to use both eyes together effectively. Vision therapy before surgery can improve any remaining binocular vision skills and make post-surgical fusion easier.
After surgery, vision therapy helps stabilize the new alignment and reduces the chance of the eyes drifting back to their previous position. This combined approach often produces better long-term outcomes in appropriately selected patients, especially in those who had some binocular potential before surgery. We create an individualized plan that sequences surgery and therapy in the order that makes the most sense for your situation.
Recovery, Follow-Up Care, and Home Support
After surgery, your eye will be red and may feel scratchy or sore for several days to a few weeks. Your surgeon will prescribe eye drops, often a steroid or a steroid-antibiotic combination, based on their routine. You can usually return to most normal activities within a few days, though we may restrict swimming and strenuous exercise for several weeks.
- Mild to moderate pain that improves with over-the-counter pain relievers
- Redness that gradually fades over two to four weeks
- Some double vision initially as your brain adjusts to the new eye position
- Temporary limitation in eye movement that typically resolves within weeks
- Blood-tinged tears and stringy discharge are common for a few days
- Visible knots or redness on the white of the eye are normal and fade over weeks
- Do not rub the eyes; consider a shield during sleep if rubbing is likely
- Do not drive until double vision has resolved and you feel safe to do so
Your active participation at home is essential for vision therapy success. We will teach you specific exercises to practice daily, and consistency matters more than the length of each session. Creating a regular time and comfortable space for exercises helps build the habit and keeps you on track.
Family members can support the process by encouraging practice without nagging and celebrating small improvements along the way. For children, making exercises fun and offering small rewards for completion can boost motivation. Keep a log of your home sessions so we can track compliance and adjust the program based on what you are actually able to accomplish at home.
We may recommend patching the stronger eye to prevent or treat amblyopia in the weaker eye, primarily in children. The number of hours per day depends on the severity of amblyopia and age. Atropine penalization or Bangerter filters can be alternatives to patching in selected cases.
Getting children to wear their patch can be challenging, but creative strategies help. Decorating patches with favorite characters, scheduling patch time during enjoyable activities like screen time, and giving positive reinforcement all improve compliance. For school-age children, we can provide a letter explaining the medical necessity of patching to share with teachers. Consistent patching produces better results than sporadic compliance.
Important safety points: never patch both eyes. Excessive patching in very young children can cause occlusion amblyopia in the better eye, so follow the prescribed hours closely. Adults rarely gain meaningful acuity from patching, though temporary occlusion may be used to control bothersome diplopia.
Strabismus treatment requires ongoing monitoring even after initial correction. We schedule follow-up appointments at regular intervals to check that your eyes remain aligned and that vision is developing properly. Children need more frequent visits during critical periods of visual development, while adults may need less frequent monitoring once stability is achieved.
Some patients need additional adjustments over time as they grow or as their eyes age. A second surgery is not uncommon, and this does not mean the first surgery failed. Your prescription for glasses or prisms may also need updates as your visual needs change. We partner with you for the long term to maintain the best possible alignment and visual function.
While most strabismus treatments are safe and effective, complications can occur. After surgery, contact us immediately if you develop increasing pain, discharge, or vision loss. Persistent or worsening double vision beyond the expected adjustment period may indicate that additional treatment is needed.
- Return of eye misalignment weeks or months after surgery
- Development of amblyopia despite patching and therapy
- Infection or excessive inflammation after surgical procedures
- Lack of progress after several months of vision therapy
- New symptoms like headaches or difficulty with balance
- Severe pain, nausea, or vomiting that does not improve with prescribed medication
- Fever or increasing eyelid swelling after surgery
- Eye bulging, worsening redness, or rapidly decreasing vision
- New inability to move the eye in a direction, suggesting a slipped muscle
Frequently Asked Questions
Treatment should begin as soon as strabismus is detected to give your child the best chance of developing normal binocular vision. The visual system is most adaptable in the first few years of life, so early intervention can prevent permanent vision problems. However, treatment can benefit people of any age, and adults can still achieve improved alignment and reduced double vision even if childhood strabismus was never addressed.
Adults with certain types of strabismus can benefit from vision therapy, especially if they have convergence problems or intermittent deviations. While the adult brain is less flexible than a child's, targeted exercises can still improve eye coordination and reduce symptoms. Surgery may be necessary for large or constant misalignments, but vision therapy can complement surgical correction or serve as the primary treatment for milder cases.
Some patients experience a drift back toward misalignment over time, especially if they had a large initial deviation or developed strabismus at a very young age. Wearing prescribed glasses, continuing eye exercises, and attending follow-up appointments help maintain alignment. If misalignment returns, additional treatment such as another surgery or renewed vision therapy might be recommended based on the degree of drift and symptoms.
Our decision depends on the type, size, and constancy of your misalignment, your age, the presence of binocular vision, and your treatment goals. Small intermittent deviations with preserved binocular function often respond to vision therapy, while large constant deviations typically require surgery. We consider your overall health, ability to comply with therapy, and how much the strabismus impacts your daily life when designing your personalized treatment plan.
Children can usually continue most sports during vision therapy and after the initial healing period following surgery. We may recommend protective eyewear during contact sports to safeguard the eyes, especially if your child wears glasses. After surgery, we typically advise avoiding swimming and activities with high risk of eye trauma for three to four weeks. Once cleared, returning to physical activities can actually help reinforce the eye coordination skills developed through treatment.
No. Do not drive until double vision is controlled with a patch or prism, or until it has resolved after treatment. Your clinician will advise when it is safe to return to driving based on your visual function.
Getting Help for Strabismus
If you or your child shows signs of eye misalignment, schedule a comprehensive eye examination with our eye doctor. Early evaluation allows us to determine the cause and severity of the strabismus and recommend the most appropriate treatment for your situation. We will guide you through every step of care, from initial diagnosis through treatment and follow-up, to help you achieve the best possible visual outcome and quality of life.