Nonstrabismic binocular visual anomaly_ fusion convergence dysfunction

Nonstrabismic binocular visual anomaly: fusion convergence dysfunction

Fusional vergence dysfunction (FVD) is an easily overlooked abnormality of binocular vision that sometimes cannot be grouped into a specific type, and the patient's symptoms and test findings are not always identical. Therefore, the diagnosis of this dysfunction is much more difficult than the diagnosis of insufficient and over-strong collections. Fusion convergence dysfunction generally occurs in school-age adolescents but can also occur in adults, especially when patients have binocular visual dysfunction, such as insufficient aggregation, prolonged in a compensatory state, prone to symptoms. Clinically, such patients can be found to have normal AC/A, distant and near optic heterogeneous oblique within the normal range, and often fusion convergence function within the normal range, but the flexibility of fusion may be problematic. 1. Symptom 1: Blurred vision during distance vision and/or near vision. 2. Discomfort after working in close proximity. 3. Symptoms worsen over time and can be more pronounced every night. 4. After using your eyes at close range for a long time, your concentration decreases and you can't concentrate. 5. You want to avoid working in close proximity for long periods of time as much as possible. 6. Initial binocular visual examination (eg, occlusion test, convergence proximity, stereopsis examination) does not explain some of the visual-related symptoms. 7. Pain above the eye every night or after studying work at close range. 2. SignsSome signs may not necessarily appear in each patient's body, and in addition, the time of each follow-up visit is different, and the examination results may not be exactly the same. Common signs are as follows. 1. Normal or near-abnormal heterogeneous measurements Measurements of heterogeneous skew may not be consistent at the beginning and end of the test. 2. Decreased positive and negative fusion convergence function During the convergence function measurement, it was found that the patient recovered slowly between the convergence and divergence function tests. 3.AC/A AC/A is mostly normal. 4. Convergence perisporum slightly decreased (generally greater than 6 cm) or normal. 5. Negative relativity regulation (NRA) and positive relativity regulation (PRA) were both decreased. (Normally, the NRA is +2.50 and the PRA is -3.50). 6. Accommodative flexibility test (+2/-2 D reversal slap) The flexibility of binocular accommodative flexibility was significantly worse than that of monocularity, and the patient was slower to eliminate blurred images of both positive and negative lenses. 7. Convergence and dispersion flexibility test (application of 3BI/12BO prism) The convergence and dispersion flexibility decreases, generally less than 15 cycles/min. 3. Diagnosis: Examination at different times of the day, the results may not be completely consistent, such as some signs appear only in the evening, and the examination in the morning may not be meaningful. 1. Take a medical history - find out the patient's age, reading habits, whether the symptoms are related to these functional causes, severity (whether it affects close reading and work), triggers at the time of symptoms, accompanying symptoms, alleviating factors, and whether there are some neurological symptoms at the same time. 2. General ocular examination and refractive examination If the patient has uncorrected refractive error, refractive correction should be performed first, and then binocular vision function test should be performed on the basis of refractive correction. 3. Observe some symptoms outside the eye Exophthalmos may be a manifestation of hyperthyroidism, and there may be vertical ocular deviation when the head is tilted. 4. It is necessary to understand the binocular vision of distant vision If the patient has obvious symptoms of distant vision, the degree of heterosis and the extent of fusion convergence must be tested. 5. Measurement of near binocular vision function includes occlusion test, near horizontal heterogeneous oblique measurement, converged proximal measurement, AC/A, fusion convergence and dispersion range, adjustment flexibility, adjustment amplitude measurement, convergence and dispersion flexibility measurement, etc. The convergence perimeter test and the flexibility test must be repeated after all examinations to understand the effect of fatigue on the test results. 6. Stereopsis Measurement of stereopsis is also required, as a decline or loss of the chain of stereopsis may indicate the presence of strabismus. 7. Ciliary muscle palsy dilated refraction can rule out latent refractive error. 4. Differential diagnosis 1. Uncorrected refractive error Farsightedness, myopia, astigmatism, especially anisometropia in both eyes, will affect the effectiveness of binocular visual function. 2. Binocular unequal image This is a relatively rare situation, because the size of the binocular image is unequal, beyond the scope of binocular fusion. It is usually seen in both eyes with large anisometropia or after surgery, such as after cataract surgery. After other binocular vision abnormalities have been ruled out, if the patient has significant factors contributing to binocular unequality, some optical approach must first be used to eliminate binocular inequality. 3. Vertical heterogeneous imbalance in the vertical direction can easily affect fusion and lead to secondary binocular vision dysfunction. Patients may sometimes have a tilted head position, which often indicates the presence of a vertical oblique bucket, and the use of prism may improve symptoms. 4. Hyperthyroidism: Exophthalmos may present with some signs and symptoms of near-eye vision dysfunction. However, the results of each follow-up examination are unstable and fluctuated, and cannot be classified as a specific binocular vision dysfunction, and the symptoms and signs are more obvious after repeated tests, and patients may be accompanied by symptoms such as proptosis, eyelid insufficiency, diplopia, and blurred vision. 5. Treatment principle 1. Glasses Fusion convergence dysfunction is easy to appear in some patients who have not undergone refractive correction and latent hyperopia, so for some symptomatic patients with low-grade hyperopia, ciliary muscle palsy pupil dilation examination must be performed, and then refractive correction must be performed. 2. Prism If the patient has a vertical offset, prism correction is required before training. 3. Visual training, such as Brock, reverse beat, etc.。