Services / Paediatric ophthalmology / Treatment of strabismus

Treatment of strabismus



What is strabismus?

Strabismus is characterized by misalignment of the eyeballs and lack of coordination of their movements. The muscles that move the eyeballs do not work precisely, and as a result the presence of strabismus prevents proper vision. Causes of this condition include trauma, visual impairment, congenital defect, ocular nerve palsy and cataracts.

It is important to remember that the popular claims that strabismus is ‘normal’ and that it is possible to ‘grow out of’ strabismus are simply not true. The treatment of strabismus should be undertaken as soon as possible! With timely treatment, parallel eye alignment can be achieved and good binocular vision can be maintained. Delaying the treatment or ignoring it altogether can lead to permanent loss of binocular vision.

What might concern parents?

Young children often do not understand what it means to ‘see properly’. This is why parents should observe them all the more carefully.

When a child squints their eyes and blinks frequently, rubs their eyes, complains of frequent headaches, watches TV, or looks at the computer or telephone screen from too close a distance, an appointment should be made with a paediatric ophthalmologist.

You should be particularly alert to these signals if either parent has a refractive error, or if there is strabismus or visual impairment in the close or extended family.


Diagnostics and ophthalmic examinations in the treatment of strabismus
The treatment of strabismus in children should be undertaken as soon as possible, as sometimes the symptoms of strabismus appear as early as when children are 3 months of age.

Strabismus occurs in various forms, e.g. as covert, concomitant or paralytic strabismus. The most characteristic symptom of strabismus is a visible misalignment of the eyeballs and sometimes an intermittent ‘escape of the eye’ to the side or nose. However, this symptom is not visible in the case of so-called covert strabismus. You should therefore be alert to any worrying signs in your child, such as headaches, eye pain, squinting the eyes, rubbing them frequently, tilting the head, holding a book too close to the eyes, watching television or looking at a monitor from too close a distance. Ophthalmic examinations for strabismus are not painful, but can be tiring for the child. They therefore require cooperation and discipline on the part of the young patient. At Retina, the parent can accompany the child throughout the consultation, and we try very hard to make the stress of the examination as low as possible for the child.

How to prepare the child for an eye examination?

  • if the child is of school age, talk to them a few days before the appointment and explain why they need to have an eye examination,
  • it is a good idea to make your child familiar with the ophthalmologist, e.g. by showing his or her photo on a website, pointing out on a map where he or she works, and talking much as possible about the planned appointment,
  • younger children can be prepared for an ophthalmic consultation by getting engaged in games that resemble an eye examination, e.g. following a moving light source, pointing from a distance to an object or colour and naming it.

 Treatment of strabismus

The treatment begins with making diagnosis and identifying the cause of the strabismus. The aim of treatment is to align the eyes correctly and thus achieve the best possible binocular vision.

Strabismus interferes with the formation of correct images in the brain, making stereoscopic (spatial) vision difficult or sometimes completely impossible. At the beginning the ophthalmologist must determine whether the child’s problems with vision are related solely to the visual impairment or also to the strabismus, as low vision can be an independent health condition, or it can accompany strabismus.

Visual impairment is treated by fitting appropriate glasses, covering up the better (dominant) eye and orthoptic exercises. The treatment of strabismus and the treatment of visual impairment require teamwork.

An ophthalmologist performs an eye examination and determines the cause of strabismus, then an optometrist compensates for the refractive error with corrective glasses, and finally an orthoptist conducts vision improvement exercises and assigns exercises to be done at home. The whole process is supervised by an ophthalmologist.

When accommodative strabismus is diagnosed often all that is needed to cure the problem is prescription of the right corrective glasses. Accommodation is the eye’s ability to automatically adjust focus from seeing things at a distance to seeing nearer objects. Children with accommodative esotropia are usually hyperopic i.e. wear corrective glasses with plus power. The eyes cross only when they do not wear their glasses.

Sometimes the strabismus is so severe that the treatment starts with a surgery during which the eyes are aligned.

Only when they are properly aligned, corrective glasses are fitted and vision improvement exercises can be started. In complicated forms of strabismus even several surgeries may be necessary.

What to expect at the basic initial examination for strabismus?

At the beginning the ophthalmologist takes a general medical and ophthalmological history from the child’s parent. The parent is asked about the most important medical facts, illnesses and burdens in the family, and possibly goes through the results of examinations performed in other clinics (if there are any).

The doctor then performs tests for:

  • visual acuity – the test involves identifying from a distance pictures presented on a special board; the pictures gradually decrease in size.
    Young children identify drawings of animals or objects, older children read special signs.  Visual acuity test allows for approximate determination of refractive error and it helps to establish whether the child has problems with distance or near vision in addition to the visible strabismus.
    Visual acuity test is not performed in children who are unable to understand instructions, as the patient’s cooperation with the doctor is crucial here.
  • refractive errors  – the test is performed after paralysing the accommodation of the eye, i.e. after dilating the pupils. This is done with mydriatic eye drops containing atropine or cyclopentolate. In young children the drops are generally instilled 3 times a day for 2-3 days before the examination. In older children, from around 10 years of age, mydriatics for adults are administered immediately before the visit. The use of medication that paralyses accommodation causes temporary blurring of near vision (usually lasting from a few hours up to 3 days). When eye examination requires pupil dilation it is necessary to ask the ophthalmologist whether the child can participate in school activities afterwards.
  • fundus examination – the test is performed after paralysing the accommodation of the eye, so it is often done together with the refractive error test. It aims to exclude changes in the retina and optic nerve. The test is performed with a magnifying tool called ophthalmoscope (a device shaped like a larger pen, with a powerful point light source and magnifying lens) at very close proximity to the patient’s eye. The doctor shines a bright light into the patient’s eye while observing what is happening in the posterior segment, i.e. at the bottom of the examined eyeball. The examination takes a few minutes and is completely painless.
  • synoptophore test – the test is performed with a synoptophore, which is a device that measures the angle of strabismus and helps to determine the level of binocular vision. The device consists of two separate telescopes through which a child sees two different images. For example, they see a lion with one eye and a cage with the other. The task for the child is to ‘put the lion in the cage’ – by performing the task correctly the child demonstrates binocular vision. At the beginning of the test both images are backlighted with the same intensity. Attention is paid to the reflection of the light on the cornea – it should fall on the centre. When the light reflection is symmetrical, one of the images is switched off. The position of the eye should not change when the image disappears. If the eye starts to “run away”, the telescope is adjusted so that the light again falls on the centre of the cornea.

The light is turned on and off until the setting movement of the eye stops. The setting of the telescopes marks the angle of the strabismus. In addition, the synoptophore is used to establish whether the images from the two eyes merge, so we can check whether the child has stereoscopic (i.e. spatial) vision.

Caution: mydriatic eye drops must not be used in children with previously diagnosed closed-angle glaucoma!

Is strabismus surgery safe for children?

Strabismus surgery is one of the relatively safe ophthalmic procedures. It involves strengthening, weakening or moving specific ocular muscles. In a nutshell, we can say that a weaker muscle is strengthened and a stronger one is weakened. The procedure is performed simultaneously on 1-3 muscles of one eye.

The surgery can be performed on one or both eyes, sometimes one procedure is enough, sometimes more are needed – it depends on the type of strabismus and the individual needs of a particular patient. The surgical correction of strabismus takes between 1 and 2 hours and is always performed under general anaesthesia in an operating theatre, with an anaesthetist and full medical staff present.

After the surgery the child spends approximately 2 -3 hours in the recovery room, after which they are discharged and can go home the same day. Due to sanitary regulations, the parent cannot accompany the child during the surgery – they wait in a dedicated place near the recovery room.

Recovery after strabismus surgery takes several days. During this time the patient must avoid sudden stooping down and tensing of the abdominal muscles. Patents are not allowed to touch, rub or put pressure on the operated eye/eyes and must be careful when washing their face.

It is also recommended to abstain from doing sports. For a few days after the surgery the patient may experience slight pain or discomfort in or around the eye, sometimes bruising, haematomas and tenderness may appear in the eye area.