In adults, evidence of the effectiveness of various non-surgical interventions is less clear.Both positive fusional vergence (PFV) and negative fusional vergence (NFV) can be trained, and vergence training should normally include both. Surgical correction options are also available, but the decision to proceed with surgery should be made with caution as convergence insufficiency generally does not improve with surgery. Bilateral medial rectus resection is the preferred type of surgery. However, the patient should be warned about the possibility of uncrossed diplopia at distance fixation after surgery. This typically resolves within one to three months postoperatively. The exophoria at near often recurs after several years, although most patients remain asymptomatic. Reading difficulty
In some cases, convergence Insufficiency can be the underlying cause of difficulty learning to read. As a result of the eyes not converging on the same point for sustained periods of time when reading, words can appear blurry or double because the brain is receiving two different images. Convergence insufficiency is not a learning disability. However, some children with the condition who are struggling to learn to read can be confused for having dyslexia due to difficulty learning to read. Children struggling with symptoms such as letters appearing blurry or double and experience tiredness or headaches when reading should consult an optometrist. Prevalence
Among fifth and sixth grade children convergence insufficiency is 13%. In studies that used standardized definitions of convergence insufficiency, investigators have reported a prevalence of 4.2% to 6% in school and clinic settings.
Convergence insufficiency is a sensory and neuromuscular anomaly of the binocular vision system, characterized by a reduced ability of the eyes to turn towards each other, or sustain convergence. Symptoms
The symptoms and signs associated with convergence insufficiency are related to prolonged, visually demanding, near-centered tasks. They may include, but are not limited to, diplopia (double vision), asthenopia (eye strain), transient blurred vision, difficulty sustaining near-visual function, abnormal fatigue, headache, and abnormal postural adaptation, among others. In some cases, difficulty with making eye contact have been noted as a complaint amongst those affected. Note that some Internet resources confuse convergence and divergence dysfunction, reversing them. Diagnosis
Diagnosis of convergence insufficiency is made by an eye care professional skilled in binocular vision dysfunctions, such as an orthoptist, to rule out any organic disease. Convergence insufficiency is characterized by one or more of the following diagnostic findings: patient symptoms, high exophoria at near, reduced accommodative convergence/accommodation ratio, receded near point of convergence, and low fusional vergence ranges and/or facility. Some patients with convergence insufficiency have concurrent accommodative insufficiency—accommodative amplitudes should therefore also be measured in symptomatic patients. Convergence insufficiency can cause difficulty learning to read. Treatment
Convergence insufficiency may be treated with convergence exercises prescribed by an eyecare specialist trained in orthoptics or binocular vision anomalies (see: vision therapy). Some cases of convergence insufficiency are successfully managed by prescription of eyeglasses, sometimes with therapeutic prisms. Pencil push-ups therapy is performed at home.