Orthoptics

The word Orthoptics comes from the Greek "Ortho" and "Optika", which translates into the expression "right eyes" and is therefore closely related to strabismus.

Orthoptics is a recent speciality, which is dedicated to the study of binocular vision by identifying, qualifying and quantifying the anomalies of vision and ocular motility. Due to its specificity, orthoptics is an area of ophthalmology in which synergy between the orthoptist and the ophthalmologist is essential.

Binocular vision anomalies can affect children and adults, however it is in the first years of life that we must guarantee a correct development of the visual system in order to avoid a compromise of the binocular vision. Therefore, orthoptics is a very useful complementary speciality to paediatric ophthalmology.

Within the field of Orthoptics, we find several pathologies that affect binocular vision such as Strabismus, Amblyopia (lazy eye) and Convergence Insufficiencies.

Strabismus corresponds to an oculomotor imbalance where there is a visual disjunction. In this pathology both eyes cannot fix the same object simultaneously. Strabismus can be vertical or horizontal. It can also be permanent or intermittent (it is not always present), and alternating (if it is deviated in one eye or the other) or not alternating (if the deviation is always in the same eye). In order for therapy to be planned and applied correctly, a precise diagnosis of the clinical case must be made.

It is often associated with strabismus, amblyopia, (aka lazy eye). It is usually unilateral and occurs when the eye has not developed the correct vision acuity. It is generally due to refractive errors with anisometropia (significant difference in graduation between the two eyes) or due to deprivation (such as a congenital cataract). It has its genesis in the fact that these situations have not been corrected in childhood, as they can go unnoticed. When they lead to strabismus (the amblyopic eye has a tendency in children to bend due to disuse) they are more easily detected and eventually corrected.

Intermittent strabismus is associated with excessive convergence or the absence of binocular vision (because it has not developed correctly).

Over-convergence strabismus appears in most cases in children with severe hyperopia. It is caused by excessive accommodation that the child has to make when fixing close up which in turn forces excessive convergence. It is easily resolved by the use of glasses and orthoptic treatment.

Insufficiency of convergence is the inability to obtain and/or maintain adequate binocular convergence without excessive effort, especially when reading. It is characterised by a decrease in the fusion amplitudes (the distance in space at which the images of each eye can be maintained together), near and far convergence and a near point of convergence (the closest point at which the images can be maintained together) of 10 cm or more. Symptoms manifest themselves mainly in near vision. The patient may report headache complaints, generally frontal and evening (at the end of the day), blurred vision and/or diplopia (two images). The appropriate orthoptic treatment will allow the patient to achieve stable binocular vision that is more comfortable for him after several treatment sessions.

The Orthoptic Assessment with or without Synoptophore is an examination in which the binocular vision and its anomalies are studied in a very complete way.

The behaviour of the two eyes is studied simultaneously, identifying and measuring any deviations. The use of the synoptophore allows a more complete evaluation of the three degrees of binocular vision.

It evaluates and simulates simultaneous perception, the capacity of the brain to perceive two images at the same time.

The fusion, the ability to join the two images into one.

Finally stereopsis, in which the brain understands the images in space, their shape and the relationship between them in the three dimensions.

This specialised orthoptic examination makes it possible to qualify and quantify the existing deviations.

The synoptophore is very important in orthoptic treatment for stimulation of fusion amplitudes and/or amblyopias.

Alterations in binocular vision are not always evident. Orthoptic assessment is required when symptoms such as difficulty in concentrating when reading, visual tiredness, headaches after visual effort, dizziness and difficulties in three-dimensional vision are present.

The rehabilitation of binocular vision disorders is the main objective of orthoptic treatments. They consist of stimulating binocular vision through exercises that force both eyes to function simultaneously.

The most common treatment is for convergence insufficiency. The treatment is divided into twelve sessions of short duration (approximately 20 minutes), over several weeks, in which exercises that stimulate convergence to near and far are applied. The treatment is usually finished when the patient is able to control convergence. One month after the end of the treatment, a new evaluation is performed in order to confirm if there are still associated complaints and if the near convergence point and fusion amplitudes have normalised.

In cases of amblyopia in children, occlusion of the "good" eye is recommended in order to stimulate the eye with less visual acuity. This treatment is extremely important and should be accompanied by orthoptic treatment, with the use of the synptophore to stimulate the eye and its connection with the other eye in order to promote binocularity. There are other exercises that can be associated, such as the Weiss booklets and the Heidinger brushes, all aimed at stimulating the central fixation, that is, the fixation in the fovea (the central part of the macula where the image is formed).

The treatment of amblyopia is very important but also difficult for children to accept, both functionally and aesthetically. These children are sometimes subjected to discrimination, especially at school and with their peers. They also have difficulty, at least initially, in carrying out their daily tasks by seeing with only the worse eye (in cases of occlusion). It is up to the doctor, the orthoptist and the parents to find strategies to help the child overcome these obstacles. Otherwise it will not be possible to recover the vision in its entirety, in terms of binocularity, which may later reflect on the well-being of the future adult, especially in the professional activity that he or she will choose.

In cases of strabismus, once the amblyopia has been treated, it may be necessary to perform a surgical intervention on the muscles which move the eye to treat the deviation, making it easier for the two eyes to work together. The child must be followed afterwards by the orthoptist who will evaluate the need of further treatments in order to guarantee the re-establishment of binocularity.

As the speciality of orthoptics is a complementary science to ophthalmology, the most suitable professionals for monitoring are orthoptists.

At CPO you can count on a team of three Orthoptists, who work together with all the ophthalmologists.