In optics, convergence is the symmetrical and simultaneous movement of the two eyes towards the nose in near vision. Essential in binocular vision, this movement is associated with the accommodation reflex (accommodation-convergence reflex). It results in a reflex action of the eyes which focus themselves to see closely and follow an object with their gaze. So that the two eyes converge in a synchronized way towards the nose to offer a single sharp image.
Nevertheless, it happens that the eyes get out of sync and that the vision tends to split in this particular case: this is hypoconvergence.
Hypoconvergence, or convergence insufficiency, is a toculomotor ruble< /a> current caused by the oculomotor muscles. The latter, weakened or unbalanced, do not allow the eyes to synchronize and converge correctly during near vision. Thus, the eyes deviate outward and the vision doubles. This is called exophoria: a disorder of ocular parallelism that causes the eyes to deviate outward under certain conditions. This disorder does not appear and has no impact on the eye at rest. It is often compared to strabismus except that in the case of strabismus, the misalignment of the eyeballs is permanent.
Thus, convergence insufficiency only affects near vision. It is for this reason that this disorder has spread and intensified since screens have become an integral part of our daily lives. In other words, vision will not be affected other than when a person is on their phone, reading a book, working on their computer, or any other task requiring close vision.
Convergence insufficiency is the heterophoria that affects the most people. ‘people. The problem now is that a large part of the population affected by this disorder is not aware of it. Insofar as the body compensates for the disorder by adapting the posture of the individual to continue to see correctly, the lack is not felt. Nevertheless, many symptoms that are more or less bothersome for everyday life are associated with it. Pain appears because the posture taken is bad. It is therefore necessary to detect hypoconvergence in order to relieve pain and avoid certain more problematic consequences.
There are various symptoms caused by convergence insufficiency. They depend a lot on the age of the person.
Indeed, the brain compensates in order to see correctly in close vision despite the disorder, but this causes:
Depending on age and symptoms, the impact of this convergence insufficiency on the person’s posture and daily life can be more or less significant.
Let’s take two examples.
On the one hand, eye fatigue which causes complications in reading and concentrating. This is a significant problem, especially for children during learning. This can cause difficulties in remaining attentive and especially visuo-spatial dyspraxia (this is a dyspraxia that affects vision due to a lack of visuo-motor coordination and difficulties in locating oneself in space).
On the other hand, cervical and back pain. They are generally due to the fact that the body, like the brain, compensates for the disorder. The body adapts its posture to see correctly up close. Thus, the person will get into the habit of tilting the head to the side when reading to see clearly, bending the back to get even closer to an object: the body adopts a bad posture strong>. This postural imbalance not only causes pain but also pathologies in the medium term: scoliosis, hernia, sciatica, low back pain, etc.The detection and correction of an exophoria
All the symptoms mentioned above can be the cause of convergence insufficiency. In this case, it is strongly recommended to make an appointment with an ophthalmologist in order to make a complete evaluation of the vision. During this examination, the specialist will do an ocular convergence test . If an insufficiency is diagnosed, the patient is usually referred to an orthoptist. Orthoptic follow-up is a treatment based on rehabilitation exercises of the ocular muscles. During the sessions, these muscles are stimulated with the aim of regaining coordination in near vision. However, the patient must continue the exercises recommended by his orthoptist at home after the end of the sessions. If the disorder is weak, the person can be directly advised to do these exercises at home, without having to go through regular orthoptic sessions.
It also sometimes happens that the specialist prescribes the patient corrective glasses to alleviate the deficit.
To its various treatments can finally be added an osteopathic follow-up. The osteopath will treat the patient’s postural disorders caused by the exophoria. It can be an important step in order to reduce his symptoms, improve his posture and work on the functioning of the eyes in the postural system of plumb. Convergence disorder can cause imbalances in posture, so both should be treated together.
Finally, the postural balance sheet is an alternative to take into account in case of insufficient convergence. This method will not treat the disorder but will allow the practitioner to diagnose if other sensors in the postural system are responsible. In addition, he will be able to detect the impact that the disorder has had on posture. Thus, the patient can be redirected to other specialists in order to correct his posture and relieve pain.