"One of the causes of strabismus is family inheritance, since one can have a certain predisposition to suffer from this problem".


Strabismus is a loss of parallelism between both eyes. Strabismus therefore affects both eyes.

However, it is common for one eye to be dominant, to have the best visual acuity and to be directed straight ahead; while the other eye will usually have some degree of amblyopia, lower visual acuity, and be in a non-parallel position.

If the non-dominant eye is in an internal position to the optical center, it is called convergent strabismus; if external to this center, divergent strabismus; if superior or inferior, vertical strabismus.

What are the symptoms of strabismus?

An adult person, with a complete development of vision, who presents a strabismus of paralytic or mechanical cause will see the same object in two different positions, this is called double vision or diplopia.

Children in period of visual development, before the vision of an object in two different positions will respond with the suppression of the vision of one of the two eyes, this way they will not see double, and yes they can develop a lazy eye. If there is also a refractive defect, myopia or hyperopia, which can vary the angle of strabismus, it is necessary to correct this with glasses or contact lenses. 

Vertical strabismus, can be cause of torticolis, abnormal positions of the head, that will be tried to correct when the strabismus is treated surgically. It is not useful to force the child to put his head straight, since he uses this position to see better.

The most common symptoms are:

  • Double vision.
  • Crossed eyes.
  • Uncoordinated eye movements.
  • Torticollis.

Do you have any of these symptoms?

You may suffer from strabismus

What are the causes of strabismus?

  • Muscular paralysis: These are the cause of the so-called paralytic strabismus, either congenital or acquired. In the adult age they cause double vision.
  • Essential or idiopathic: they are the most frequent. It is an affectation of the ocular motor system of unknown origin.
  • Refractional: caused by an alteration of the accommodation-convergence relationship. If there is hyperopia, there is excessive accommodation to keep the image clear, which can lead to excessive convergence. They are totally or partially corrected with glasses. Strabismus that is corrected with glasses should not be operated.
  • Sensory interference: any injury that prevents a correct visual acuity can interfere with the correct development of the oculomotor balance, producing strabismus. A retinoblastoma, the most frequent malignant intraocular tumour in children, can be manifested by the appearance of a convergent strabismus.
  • Mechanical: due to anomalies in the muscles, sheaths. They are rare.

How is strabismus diagnosed?

There are strabisms that are very evident, the angle of strabismus is very big. We can diagnose a strabismus by evaluating where the corneal reflexes are projected in both eyes, and if in one eye the reflex is centered or deviated from the other.

The ophthalmologist will evaluate the angle of strabismus with the use of the so-called occlusion test or cover-test and the aid of prisms.

In every strabismus there is a risk of developing an amblyopic eye, this occurs if there is a dominant eye.

Special care should be taken to rule out amblyopia, since it is essential to begin recovery as soon as possible and to maintain it throughout the period of visual development.

How is strabismus treated?

The sensory treatment is aimed at correcting the refraction defects, and achieving a balanced and correct visual development in both eyes as well as treating or preventing the development of amblyopia.

Depending on the type of strabismus, if it is convergent, all the optical correction must be corrected in the case of hyperopia and astigmatism in a pair of glasses, which should be worn at all times.

For divergent strabismus, the ophthalmologist will indicate, depending on the type of refractive defect and vision, the correction the child should wear. For children, low-brow glasses, preferably made of paste, are recommended. It should also be taken into account whether there is an amblyopia, and how to treat it.

Depending on the type and degree of amblyopia, the occlusions will be used; or methods of penalization if the amblyopia is slight, or is recovered to avoid recurrences.

The penalty can be: optics with additional corrections in the glasses, or with interposition of filters or lacquers in the glasses that make it difficult for the dominant eye to see.

The treatment of the angle of deviation will depend on the type of strabismus. The strabismus that are called accommodative or refractional, are corrected with the glasses, in this case it will not be necessary to operate.

Only those strabismus that are not corrected with glasses and are significant will be operated on. The surgery can be performed once the child has been explored on different occasions, and the type and degree of strabismus is known. It is advisable to recover first the amblyopia and then intervene the strabismus.

In some cases of very small angles, or after surgery if there are small hiccups or hypercorrections can be used botulinum toxin. It is also being used in some very young children, < 1.5 years with congenital wide-angle strabismus.

Where do we treat it?


The Department of Ophthalmology
of the Clínica Universidad de Navarra

Equipped with the latest technology, the Department of Ophthalmology has the necessary equipment, both technical and human, to offer comprehensive and specific assistance to each patient.

We are one of the few centers that have a microsurgery laboratory for the improvement of clinical practice.

Organized in specialized units

  • Cornea and eye surface
  • Retina
  • General Ophthalmology
  • Refraction defects
  • Oculoplastic
  • Pediatric ophthalmology
Imagen de la fachada de consultas de la sede en Pamplona de la Clínica Universidad de Navarra

Why at the Clinica?

  • More than 30 years of experience.
  • Experts in the diagnosis and treatment of ocular pathologies.
  • With the security and guarantee of a prestigious hospital.

Our team of professionals