{"id":1858,"date":"2026-10-20T08:53:11","date_gmt":"2026-10-20T08:53:11","guid":{"rendered":"https:\/\/laseristanbulclinic.com\/eye-glossary\/strabismus\/"},"modified":"2026-10-20T12:57:23","modified_gmt":"2026-10-20T12:57:23","slug":"strabismus","status":"publish","type":"page","link":"https:\/\/laseristanbulclinic.com\/en\/eye-glossary\/strabismus\/","title":{"rendered":"Strabismus (Squint): What It Is, Types, Causes, Symptoms and Treatment"},"content":{"rendered":"\n
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  1. Home<\/a><\/li>
  2. Knowledge centre<\/a><\/li>
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  4. Strabismus (Squint): What It Is, Types, Causes, Symptoms and Treatment<\/span><\/li><\/ol><\/div>\t\t\t

    Strabismus (Squint): What It Is, Types, Causes, Symptoms and Treatment<\/h1>\n\t\t\t\t\t\t

    Medically reviewed by {{surgeon}}<\/span> \u00b7 {{review date}}<\/span><\/strong> ({{surgeon’s title and specialty}}<\/span>). Last updated {{date}}<\/span>.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

    \"Illustration<\/figure><\/div>\n\t\t\t<\/div><\/div>\n<\/section>\n\n\n\n\n
    \n\t\t<\/svg>Definition<\/span>\n\t\t\t

    Strabismus<\/strong> (noun; also called squint, crossed eyes or wall eyes)<\/em>: strabismus is a misalignment of the eyes, where one eye points in a different direction from the other. The NHS describes it as eyes that point in different directions, with one eye turning in, out, up or down while the other looks straight ahead. It can be present all the time or come and go, and it affects children and adults. At Laser Istanbul Clinic, squint in children and adults is assessed and operated on by Prof. Dr. Ahmet Sat\u0131c\u0131.<\/p>\n\t\t\t

    Squint versus squinting.<\/strong> In British English, “squint” is the everyday word for strabismus. “Squinting” (narrowing your eyes to see better or against bright light) is a different thing and is not a medical condition. If one eye visibly drifts, that is strabismus and needs an eye specialist.<\/p><\/div>\n\t<\/div><\/div><\/div><\/div><\/section>\n\n\n\n\n

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    Strabismus (squint): key facts<\/h2><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t
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    <\/svg>Medical name<\/span><\/dt>
    Strabismus; “squint” in UK usage, “crossed eyes” for an inward turn<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>What it is<\/span><\/dt>
    Eyes that do not line up: one eye turns in (esotropia), out (exotropia), up (hypertropia) or down (hypotropia)<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>How common<\/span><\/dt>
    About 2.1% of children (Royal College of Ophthalmologists); about 4% of the US population (AAPOS)<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Main types in children<\/span><\/dt>
    Roughly 60% turn inwards and 20% outwards (Royal College of Ophthalmologists)<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Main risk to a child's sight<\/span><\/dt>
    Amblyopia (lazy eye), because the brain can start to ignore the misaligned eye<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Usual first treatment<\/span><\/dt>
    Glasses if the squint is linked to a focusing problem, then treatment of any lazy eye, then eye muscle surgery if a turn remains<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Specialist<\/span><\/dt>
    Ophthalmologist with squint expertise, often working with an orthoptist; at Laser Istanbul Clinic, Prof. Dr. Ahmet Sat\u0131c\u0131<\/dd><\/dl><\/div>\n\t\t\t<\/div>\n\t\t<\/div><\/div><\/div><\/section>\n\n\n\n\n
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    What is strabismus? Types of strabismus<\/h2>\n\t\t\t

    Strabismus is named by the direction the eye turns, and by whether the turn is constant or intermittent.<\/strong> AAPOS lists the main groups as horizontal (esotropia and exotropia) and vertical (hypertropia and hypotropia), plus special forms such as Brown syndrome, Duane syndrome and palsies of the cranial nerves that move the eye.<\/p>\n\t\t\t

    Type<\/th>What happens<\/th>Key facts<\/th><\/tr><\/thead>
    Esotropia<\/strong> (“crossed eyes”)<\/th>One eye turns inwards, towards the nose<\/td>EyeWiki (American Academy of Ophthalmology) separates infantile esotropia (starting before 6 months of age), accommodative esotropia (linked to uncorrected long-sightedness, the most common subtype) and acquired forms<\/td><\/tr>
    Exotropia<\/strong> (“wall eyes”)<\/th>One eye turns outwards, towards the ear<\/td>AAPOS describes intermittent exotropia, where the eye drifts outwards when the person is tired, ill or not paying attention, and sensory exotropia, where one eye has much reduced vision. Intermittent exotropia affects about 1% of the general population and makes up about 75\u201390% of exotropia (EyeWiki)<\/td><\/tr>
    Hypertropia<\/strong><\/th>One eye sits higher than the other<\/td>A vertical turn, which can follow a nerve palsy or an eye muscle problem<\/td><\/tr>
    Hypotropia<\/strong><\/th>One eye sits lower than the other<\/td>The same misalignment seen from the other eye: a hypertropia in one eye is a hypotropia in the other<\/td><\/tr>
    Constant or intermittent<\/strong><\/th>The turn is present all the time, or only sometimes<\/td>The Royal College of Ophthalmologists classes strabismus as intermittent or constant, infantile or acquired, accommodative or non-accommodative, comitant (same angle in every direction of gaze) or incomitant (changes with gaze direction)<\/td><\/tr><\/tbody><\/table><\/div>

    Tropia and phoria.<\/strong> A tropia<\/em> is a visible turn. A phoria<\/em> is a tendency for the eyes to drift that the brain normally keeps in check. EyeWiki describes intermittent exotropia as progressing from exophoria (a latent drift) to exotropia (a visible one).<\/p>\n

    Is it true strabismus or “pseudostrabismus”?<\/h3>\n

    Pseudostrabismus is when the eyes look as if they are not straight, but they actually are. AAPOS says it is usually caused by a flat nose bridge and small skin folds at the inner corners of a baby’s eyes, which are most noticeable in photographs when a child looks sideways. It needs no treatment and often improves as the child grows, but only an eye examination can tell the two apart, and AAPOS advises regular check-ups because these children can develop true strabismus later.<\/p><\/div>\t<\/div><\/div><\/div><\/section>\n\n\n\n\n

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    What causes strabismus (squint)?<\/h2>\n\t\t\t\t\t\t

    Strabismus has many causes, and in most cases the cause lies in how the brain controls eye movement rather than in the eye muscles themselves.<\/strong> AAPOS states that most cases come from abnormal neuromuscular control of eye movement in the brain, and less often from a problem with the muscles.<\/p>\n\t\t\t\t\t\t

    In children,<\/strong> the NHS lists these causes:<\/p>\n