Orthoptic visit of G.Bertelli

Generality

The orthoptic examination is an eye examination that serves to diagnose the muscular and sensory deficits that affect the visual apparatus.

This evaluation is divided into various tests and involves, among other things, the examination of visual acuity .

The orthoptic examination is useful for understanding the causes that determine the various forms of strabismus, accommodation and convergence defects and amblyopia (also known as "lazy eye"), also intervening on the resulting symptoms, such as alterations of the visual field, postural abnormalities and double vision .

The orthoptic examination can also be useful in the presence of other ocular problems (eg traumatic incidents, particularly strenuous work for the eyes, dyschromatopsia, etc.) and allows you to plan the most appropriate rehabilitation path for the patient.

What's this

The orthoptic examination is a very important ophthalmologic evaluation that allows the identification of binocular vision anomalies, verifying the degree of collaboration between the two eyes . This test is used, in particular, to confirm or exclude the presence of disorders of the neuromuscular apparatus and the alterations deriving from them (such as strabismus, amblyopia, suppression mechanisms and ocular paralysis).

The orthoptic examination involves the evaluation of ocular motility, in the sense of:

Three-dimensionality ("stereopsis");
Convergence;
Movements that allow the eyes a unitary vision;
Accomodation.

Why do you run

The orthoptic examination is useful for the diagnosis or evaluation of the risk factors that can predispose to:

Disorders that reduce or prevent binocular vision, such as strabismus and amblyopia;
Severe visual impairments ( low vision );
Astenopia or visual fatigue syndrome, which can affect those who spend many hours on the computer or digital devices for work or leisure.

The orthoptic examination is an assessment aimed at both children and adults .

Diagnostic scope

The orthoptic examination is useful above all to highlight the restrictions in the movement of the extraocular muscles in the various gaze positions, both for each individual eye and when they work together (examination of ocular motility).

The examination checks the convergence of the gaze and, in cases of strabismus, allows us to quantify the extent of the deviation, identify which muscle causes diplopia (double vision) and follow the evolution of the clinical picture over time.

The orthoptic examination also evaluates the sensitivity to chromatic contrast and dyschromatopsia (difficulty in the perception of colors).

Orthoptic treatment of visual rehabilitation

As far as the therapeutic field is concerned, the orthoptic examination plays an important role in the monitoring of amblyopia (a condition that produces unilateral reduction of vision), since it follows the evolution of the improvement of visual capacity by intervening, depending on the specific case, with orthoptic exercises or possible bandages. The orthoptic is also useful for the definition of rehabilitative pathways in patients suffering from neurological pathologies or who have suffered a head injury, as well as providing support in the event of postural changes, dyslexia or learning disabilities .

Orthoptic visit: when is it indicated?

The orthoptic examination is important for the diagnosis of various pathologies, which affect binocular vision, reduce motor skills (in particular, in driving or in manual dexterity tasks that require speed and precision) and, in the child, may cause a delay in the development (as in walking and speaking).

In this regard, it should be noted that this exam is part of the protocol dedicated to pediatric prevention :

In the first 6-8 months of life, the orthoptic examination serves to exclude the presence of congenital pathologies or high visual defects that can cause important damage to vision, but if they are detected and treated early they are easier to manage.
If everything goes smoothly, the next check should be made between two and three years . In this age group, the child is able to distinguish simple symbols and, if managed in a quiet manner, collaborates with the eye doctor, for which it will be easier to assess the presence of any sight defects, such as amblyopia.
In pre-school age (5-6 years), the ophthalmologist checks eyes even more accurately than the previous one: the child, in fact, in addition to recognizing drawings and letters, can interact with the doctor by answering his questions. The control serves to verify that the development of the visual system is proceeding correctly and that there are no difficulties in binocular cooperation such as to influence reading and writing.

In adulthood, the orthoptic examination is aimed at people suffering from general or specific diseases of the visual system that induce symptoms such as diplopia, visual field alterations or postural defects.

Altered Values - Causes

The orthoptic examination allows to highlight the conditions that alter coordination and ocular motility and affect binocular vision, determining:

Lazy eye (amblyopia);
Anisometropia (condition in which the two eyes have a different refraction);
Double vision (diplopia);
Strabismus and other convergence defects of the visual axes of the two eyes;
nystagmus;
Ocular paralysis.

Following the orthoptic examination and other tests, the doctor will prescribe the most appropriate treatment for the disorder he has encountered. The orthoptic examination is also able to control the evolution of already diagnosed pathologies.

How the exam takes place

The orthoptic examination is an exam that is carried out, in an outpatient procedure, by the ophthalmologist (eye disease specialist) or by the orthoptist (health professional who supports the doctor in performing the tests).

After a thorough medical history, the evaluation begins with a check aimed at excluding the presence of limitations of the muscles responsible for moving the eyeballs, both for each single eye and in simultaneous vision.

Subsequently the ability to fix objects on approach ( convergence ) and that there are no points in the space in which the vision is split is checked .

During the examination, the doctor verifies the visual acuity, that is, how much the patient is able to see clearly; in general, the patient is asked to recognize some optotypes (graphic symbols, E of Albini, letters or numbers) arranged at a precise distance.

Once this first phase has been completed, the orthoptic examination involves the execution of specific tests that allow to deepen the clinical picture.

The main orthoptic tests

The most used orthoptic techniques include:

Stereopsis : during the orthoptic examination, this test evaluates the sense of depth and the three-dimensional vision, which can be defective if there is no correct synergy between the two eyes (as can happen, for example, for very different visual defects in an eye) and the other).
Convergence : it is an orthotic test that evaluates the ability of the two eyes to perform a harmonic and symmetrical movement when they are stimulated to converge, making an object that progressively approaches the tip of the nose be fixed. This evaluation is very useful in those who use a video terminal for a long time. As far as the convergence movement is concerned, the orthoptic examination can also verify the fusion amplitudes, that is the collaboration capacity of the two eyes in merging two distinct images into a single image and maintaining this uniqueness even when they are stimulated to converge or diverge.
Examination of ocular motility (MOE) : during the orthoptic examination, check the functionality of the muscles that move each eye, in the main gaze positions. This test allows to highlight a limited ocular motility, the possible misalignment of the eyes and the nystagmus. The examination of ocular motility serves to identify the presence of hyper and / or hypofunction to the extraocular muscles (such as, for example, the deficiency of the external rectus muscle, which is involved in the paralysis of the VI cranial nerve), coordinated movement anomalies of the two eyes (eg convergence deficit), particular conformations of the facial massif such as to induce pseudo or real strabismus (eg epicanthus, orbital strabismus, etc.).
Test for the study of diplopia : this evaluation of the orthoptic examination verifies the manifestation of double vision (a single image is perceived as double) and its relative nature (horizontal, vertical and oblique). Therefore, the doctor pays particular attention to the way the eyes concentrate and move together to focus a visual stimulus (alignment, convergence and focus). Any deficits found may suggest the presence of injuries to the eye or eyelid, an orbital or retrobulbar disorder, etc.
Cover test : serves to highlight the presence of strabismus, classifying them in posters (always present) or latent (they emerge only in certain circumstances), in addition to indicating in which direction the ocular deviation (convergent, divergent, vertical or torsional) occurs. If combined with the use of a prism stick, the cover test allows to measure the power of the prism lens needed to compensate for the deviation.
Screen examination of Hess Lancaster and Gracis : in the presence of strabismus, this orthoptic examination test serves to quantify the degree of deviation and the state of the muscles affected by the problem. This examination is preliminary to surgery.
Test for the evaluation of the sensoriality: it examines the binocular relationships and the retinal correspondence of the two eyes (that is, how much they "collimate" the two images that are formed on the retina of the two eyes). This test allows to detect the presence of vision sensory abnormalities such as suppression (ie an eye is not used due to the poor quality of the image it provides to the brain). The fusional and accommodative performance is altered in the case of strabismus and / or amblyopias.

How long does it last?

The duration of the orthoptic visit is variable, but, generally, it takes 15-20 minutes.

What does the report contain?

The diagnostic conclusion is reported in the report of the orthoptic examination prepared by the ophthalmologist.

Preparation

The orthoptic examination is performed during an eye examination. To undergo the examination, there is no special preparation by the patient.

Some tests can be performed without the instillation of eye drops, so that the ophthalmologist can assess how the eyes respond under normal circumstances.