Strabismus (Eye Turn)

Strabismus is a condition where the eyes are not always aligned in the same direction.

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One eye may turn inward, outward, upward or downward, and the eye turn may be present all the time or only at certain times, such as when tired, unwell or focusing at a particular distance.

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Strabismus is sometimes called a “lazy eye,” but this is different from amblyopia, where vision is reduced in one eye because normal visual development has been disrupted.

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What Are the Different Types of Strabismus?

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Eye turns are usually described by the direction the eye moves:

• Esotropia – the eye turns inward;

• Exotropia – the eye turns outward;

• Hypertropia – the eye turns upward;

• Hypotropia – the eye turns downward.

An eye turn may be:

• constant – present most or all of the time;

• intermittent – only present at certain times;

• present mainly at near or distance;

• present in one eye or alternate between both eyes.

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What Causes Strabismus?

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Strabismus can develop for many different reasons.

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These may include:

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• differences in how the eye muscles or nerves control eye movement;

• significant glasses prescriptions;

• difficulties coordinating both eyes together;

• neurological or developmental conditions;

• reduced vision in one eye;

• injury or illness.

In some children, there may be no single obvious cause.

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What Are the Signs of Strabismus?

Signs may include:

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• an eye that appears to turn inward, outward, upward or downward;

• closing or covering one eye;

• tilting or turning the head to see more comfortably;

• double vision;

• difficulty judging depth or distance;

• reduced vision in one eye;

• an eye turn that becomes more noticeable when tired, unwell or concentrating.

Young children may not report symptoms because they often adapt to the way they see.

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How Can Strabismus Affect Vision?

When the eyes are not pointing in the same direction, the brain receives two different images.

In children, the brain may adapt by reducing attention to the image from one eye, which can increase the risk of developing amblyopia.

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Strabismus can also affect binocular vision and depth perception, although the impact varies depending on the type, frequency and age at which the eye turn developed.

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Adults who develop strabismus later in life are more likely to experience double vision because their visual system has not had time to adapt.

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How Is Strabismus Treated?

Treatment depends on the type and cause of the eye turn, the person's age and how the eyes are functioning together.

Management may include:

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• Prescription glasses;

• Prism lenses to help manage double vision or eye alignment in selected cases;

• Amblyopia treatment, such as patching or atropine, when reduced vision in one eye is also present;

• Vision Therapy or Orthoptic exercises in selected cases to improve specific binocular vision or eye movement skills;

• Strabismus surgery where appropriate to improve eye alignment.

Some people may require more than one type of treatment.

How Can Eyetreat Help?

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An Orthoptic Assessment can measure eye alignment, eye movements, binocular vision and vision in each eye to better understand the type and impact of the strabismus.

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Following the assessment, we can explain the findings and discuss appropriate management options. Where required, we can also work alongside your Optometrist or Ophthalmologist as part of your treatment plan.