Adult strabismus: causes, symptoms and treatment

25/11/2025

What is it?

Strabismus is an eye condition in which there is a lack of parallelism or alignment of the eyes, so that each one looks in a different direction.

It can be classified into different types. According to its direction, strabismus may be: convergent or esotropia (the deviated eye turns inwards), divergent or exotropia (the deviated eye turns outwards), or hypotropia (the deviated eye turns downwards). The deviation may appear constantly or intermittently, and may appear only at times of tiredness, fever, or lack of attention. Finally, it may be comitant, when the deviation is the same in the different positions of gaze, or incomitant, when the degree of deviation varies depending on the direction of gaze.

Although it is a condition commonly associated with childhood, strabismus can develop at any age: it is congenital if it appears before 6 months of age, acquired in childhood if it begins from the age of 2–3 years, or adult-onset if it begins in adulthood.

Causes of strabismus in adults

Adult strabismus may appear due to decompensation of childhood strabismus or may be secondary to other factors such as:

•  Neurological diseases: myasthenia gravis, multiple sclerosis or other neuromuscular diseases
• Systemic diseases: thyroid disease (thyroid orbitopathy or Graves’ disease), diabetes mellitus, arterial hypertension
• Eye diseases: high myopia
• Tumours of the central nervous system
• Cerebrovascular accidents: cerebral infarctions or haemorrhages
• Trauma: cranioencephalic or orbital trauma
• Previous eye surgery: cataracts, glaucoma, retinal detachment, eyelids (blepharoplasty), strabismus…
• Associated with age: due to laxity of the tissues involved in eye movement
• Sensory strabismus: due to low vision in one eye

Symptoms of acquired strabismus

The symptoms in adults differ from those found in childhood strabismus, since in children the brain is in full visual developmental stage and has greater plasticity, meaning it adopts suppression mechanisms (switching off one eye) to avoid diplopia (double vision) and confusion.

An adult patient with acquired strabismus may present various clinical manifestations, including:

• Diplopia or double vision: perception of two images of the same object
• Overlapping or confusion of images
• Problems with depth perception: difficulty judging distances
• Eye fatigue or asthenopia: a sensation of tiredness or discomfort in the eyes
• Headache: due to constant effort to try to compensate for the lack of alignment of the eyes
• Loss of binocular vision: reduced ability of the eyes to work together, leading to a reduction in the effective visual field
• Torticollis: abnormal head position to avoid double vision or to relieve symptoms
• Low self-esteem and increased risk of anxiety/depression: due to the psychosocial impact of the cosmetic defect caused by the deviation

In cases of decompensated childhood strabismus in adulthood, as well as in sensory strabismus, the patient does not usually experience double vision, although at times they may report asthenopia or eye discomfort.

Diagnosis

For correct diagnosis, a complete examination by a specialist ophthalmologist is essential in order to:

• Assess visual acuity and refraction (hyperopia, myopia, astigmatism)
• Examine the anterior and posterior segments of the eye
• Study eye motility and the coordination of both eyes with the visual brain (sensory examination)
• Rule out, in certain cases, the presence of systemic disease by means of neuroimaging tests and carry out joint assessment with other specialists

Treatment

Treatment will depend on the type and cause of the strabismus, and includes different therapeutic options such as:

1. Corrección óptica

Use of glasses or contact lenses. These may help correct or improve alignment in certain types of strabismus, such as accommodative strabismus.

2. Prisms

“Special” wedge-shaped lenses that modify the direction of light rays and therefore the image. They do not change the position of the eyes but relieve double vision, so they do not correct the underlying problem. They are useful in cases with small deviation angles.

3. Visual therapy

Ejercicios específicos para mejorar la coordinación binocular en determinados casos como las exoforias o exotropías intermitentes de baja magnitud con insuficiencia de convergencia fusional.

4. Botulinum toxin

A neuromodulating substance that temporarily paralyses the muscles, applied to those with excess activity to achieve rebalancing of muscle action and eye alignment. It is indicated in certain types of strabismus, such as oculomotor palsies.

5. Extraocular muscle surgery

Allows restoration of ocular parallelism and cooperation between both eyes, improves spatial perception and visual field, relieves symptoms, corrects torticollis, and improves cosmetic appearance.

6. Treatment of the underlying cause

In some cases, strabismus may require a multidisciplinary approach involving an ophthalmologist, internist, and neurologist. In some of these cases, treating the primary medical condition may itself resolve the eye alignment.

Adult strabismus compromises not only vision but also quality of life and can be highly disabling for those who suffer from it. The presence of a deviated eye can cause significant insecurity in personal relationships, and the symptoms it causes can make daily tasks such as reading or driving difficult.

Contrary to what many people believe, strabismus can be successfully treated at any age. At the Barraquer Ophthalmology Centre, we have a team specialised in the diagnosis and treatment of adult strabismus through both medical and surgical procedures.

Although it is an eye condition that cannot always be prevented, periodic check-ups with a specialist will allow early diagnosis and treatment, a better prognosis, and will prevent the development of future complications.

Dr. Idoia Rodríguez Maiztegui, ophthalmologist at the Barraquer Ophthalmology Centre