As Heterophoria This is understood to mean a latent squint that can only be seen with one-eye vision. With binocular vision in both eyes, the latent visual defect is involuntarily compensated for by the motor and sensory alignment of the two eyes through active muscle power. If binocular vision is interrupted and the direction of vision of both eyes can no longer be coordinated, most people experience a slight divergence in the visual axes of both eyes.
What is heterophoria?
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When both eyes are aligned to a point in the distance, our motor and sensory adjustment mechanisms for both eyes via the outer eye muscles ensure that the two axes of vision are precisely aligned.
Without these adjusting mechanisms, the image would otherwise be out of focus or even a double image. When the distant point approaches us and we continue to fixate it with both eyes, both lines of sight are gradually turned inwards by a few arc seconds and, in extreme proximity, by several degrees of angle.
If there is no active alignment of the visual axes when a point is fixed in the distance, and thus also the motorized adjustment mechanism of the eyes, around 80 percent of people experience a slight twisting of the visual axis of the non-active eye. De facto, this results in a slight squint.
The deviation of the line of sight of the inactive eye can be rotated slightly inwards, outwards or upwards or downwards about all three spatial axes. Combinations of the misaligned or decoupled viewing axes between inside / outside and above / below are also possible. Usually it is the Heterophoria only by a few arc seconds to a few degrees of angle by which the viewing axes deviate from parallelism.
causes
Three possible causal complexes are held responsible as the trigger and cause of the heterophoria, after which the latent strabismus is named and classified. A distinction is made between static, accommodative and neurogenic heterophoria. The static cause complex includes all anatomical components such as the eye socket (orbit) and the position and nature of the holding apparatus of the eyeball.
Accommodation heterophoria can be caused by refractive errors or by a certain form of farsightedness. Neurogenic factors for the development of a heterophoria can consist in nervous transmission problems of visual impulses.
A disturbed further processing of the signals in ganglia or in the CNS can also be a possible cause. This leads to a limited or completely unusual "image processing". Reduced neurological processing of the neuronal impulses usually also leads to the inability of the sensory image fusion of both eyes.
Symptoms, ailments & signs
In the vast majority of cases, heterophoria is only weakly pronounced. Errors in the non-parallelism of the two lines of sight when accommodating at a distance are corrected symptom-free by the motor-sensory adjustment mechanism in binocular vision. Only when the heterophoria is more pronounced is the external eye muscles so stressed by the active adjustment mechanism that unspecific symptoms appear.
Some of the symptoms and signs observed can consist, for example, in the form of headaches and blurred vision because the unconscious adjustment mechanism of the external eye muscles is overwhelmed. If the heterophoria is even more pronounced, dizziness, lack of concentration and increased sensitivity to glare can also set in.
Typically, the signs and symptoms that are grouped under the term asthenopia only appear during the day.This is most likely related to gradual fatigue in the external eye muscles.
Diagnosis & course of disease
In normal cases, in which there are no symptoms of heterophoria, this type of ametropia remains undetected and has no consequences. An examination and clarification is only recommended when symptoms increase during the course of the day. Common devices with which any kind of squint (strabismus) can be examined and clarified with differential diagnosis are the chart projector, haploscope and the much more complex phase difference haploscope.
The latent ametropia of heterophoria usually shows no further course because it often exists from birth due to anatomical features. In those cases when it was acquired due to diseases of the nervous system or due to diseases of the external muscles of the eye, the course depends on the further development of the underlying disease.
Complications
With heterophoria, the patient usually has a squint. Squinting can particularly affect children, who often lead to bullying or teasing. The patient's quality of life is generally reduced and everyday life is made more difficult. It is not uncommon for the heterophoria to cause dizziness, as the patient can only see blurred.
The visual impairments also make daily activities more difficult and restricted. Furthermore, in many cases there is headache or so-called double vision or veil vision. Concentration also decreases due to the disease, which can have a negative impact on everyday life and school performance, especially in children. Many sufferers feel dizzy and have increased sensitivity to light.
When treating heterophoria, there are usually no particular complications. The treatment takes place primarily through visual aids or surgery and does not lead to further complications. However, in most cases the surgical interventions can only be performed in adulthood, which is why children are still dependent on the visual aids.
When should you go to the doctor?
For many people, heterophoria has no disease value and does not require treatment. Up to 80% of people live with the diagnosis of heterophoria and do not notice any restrictions or complaints in everyday life. Since they describe themselves as symptom-free, no medical care is required in these cases. It is only necessary to see a doctor as soon as there are impaired vision or other complaints. If you see double vision or vision is blurred, see a doctor.
If the field of vision is perceived as blurred or unclear, it is advisable to consult a doctor. If the visual discomfort increases in intensity or scope over time, an eye test should be performed immediately. If the general risk of accidents increases or if there is an increasing number of incorrect assessments of distances, a doctor's visit is necessary. If the usual lettering on traffic signs can no longer be deciphered, this is an indication of impaired eyesight, which should be investigated.
If you have other symptoms such as headache, a feeling of pressure in the head or burning eyes, these symptoms should be discussed with a doctor. If there are disturbances in concentration, increased irritability or if tiredness sets in prematurely despite adequate night sleep, further examinations are recommended to clarify the cause.
Doctors & therapists in your area
Treatment & Therapy
There are basically three different forms of therapy for heterophoria worthy of treatment. As a passive therapy, the use of individually made glasses comes into question. The latent ametropia can be completely or partially compensated for by the lenses. This relieves the motor-sensory adjustment mechanism of the eyes, so that the typical signs of fatigue do not occur and the symptoms recede quickly.
In other cases, special eye training can already lead to success. It is a targeted eye muscle training, with which convergence training, i.e. inward movements of the eyes (near accommodation) and the avoidance of double vision, are trained. In addition to many other exercises, the visual training also includes visual relaxation exercises. The third form of therapy consists of a surgical procedure that mainly involves corrections to the external muscles of the eye.
The corrections are made in such a way that the visual axes of the two eyes are as parallel as possible after the procedure in a relaxed state. This relieves the eye muscles during distance accommodation so that there should no longer be any signs of fatigue.
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The prognosis for heterophoria can be classified as favorable. In many cases, spontaneous remission occurs after a few hours. The patient often experiences no symptoms whatsoever. The sensory stimuli are processed correctly in the brain despite the squint, so that the person concerned does not experience any impairments. The squint is perceived by those present, although the person affected does not experience any noticeable changes in vision at the moment.
Often a full recovery is already given with a sufficient night's sleep. The eye is no longer able to present its full functionality due to overexertion or overtiredness. After a restful sleep, the disruptive factors are regenerated and, therefore, full performance occurs again afterwards.
If the heterophoria was triggered by heavy alcohol consumption, complete regression is linked to the breakdown process of the pollutants from the organism. Consequential damage to the eye or permanent visual impairment is not to be expected with heterophoria. Rather, the process of squinting is seen as an indication of the body being overburdened. It occurs in almost everyone in their lifetime and is not considered to be a concern. If the heterophoria occurs more frequently, the triggering cause should nevertheless be examined more closely, as there is usually a fundamental need for action.
prevention
Direct preventive measures that could prevent the development of heterophoria do not exist. The disease develops immediately after birth due to minor genetic abnormalities or it is acquired through special neuronal or muscular diseases. This means that only indirect preventive measures are conceivable that minimize the risk of a corresponding muscle or nerve disease.
Aftercare
With heterophoria, those affected are primarily dependent on a quick and, above all, an early diagnosis, as this is the only way to prevent further complications or further worsening of the symptoms. There is also no independent healing, so treatment must be carried out in every case. Further follow-up measures are usually not available to those affected.
Parents in particular have to recognize the disease in their children at an early stage and then consult a doctor immediately. In most cases, the symptoms of heterophoria are relieved relatively well by wearing glasses. Those affected have to wear their glasses or contact lenses permanently so that the ametropia does not get worse.
Regular examinations and controls by an ophthalmologist are also very useful. In some cases, however, surgery is also necessary. After such an operation, the person affected must rest and take care of his body. Here you should refrain from exertion or physical activity in order not to unnecessarily stress the body. As a rule, the heterophoria does not reduce the life expectancy of the person affected.
You can do that yourself
Heterophoria does not always have to be treated by a doctor. If you have a slight squint, targeted eye muscle training is often sufficient. This special vision training is instructed by a specialist and can be continued independently at home. In addition, visual relaxation exercises are used, such as visual meditation or similar measures.
If the squint causes symptoms such as headaches or dizziness, it usually helps to close your eyes for a few minutes. Herbal remedies can be used for severe complaints. For example, headaches can be relieved by using essential oils. Mineral earth can also reduce the throbbing and at the same time prevent dizziness. If the concentration is insufficient, plenty of water should be drunk. A proven alternative from homeopathy is the remedy Belladonna, which can be taken in consultation with an alternative practitioner.
However, if the symptoms increase, heterophoria must be treated surgically. Then the best self-help measure is to take care of the affected eye after the procedure. According to the doctor's instructions, special care products can be used that relax the irritated eye and prevent infection. If there are any signs of inflammation, the responsible ophthalmologist must be informed.
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