Convergence insufficiency

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Convergence Insufficiency
Other namesConvergence disorder
SpecialtyOphthalmology, optometry Edit this on Wikidata

Convergence insufficiency is a sensory and neuromuscular anomaly of the

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,

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.[citation needed] Note that some Internet resources confuse convergence and divergence dysfunction, reversing them.[citation needed
]

Diagnosis

Diagnosis of convergence insufficiency is made by an eye care professional skilled in

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.[1][2][3]

Treatment

Convergence insufficiency may be treated with convergence exercises prescribed by an eyecare specialist trained in orthoptics or binocular vision anomalies (see:

eyeglasses, sometimes with therapeutic prisms
.

Pencil push-ups therapy is performed at home. The patient brings a pencil slowly to within 2–3 cm (0.79–1.18 in) of the eye just above the nose about fifteen minutes per day five times per week. Patients should record the closest distance that they could maintain fusion (keep the pencil from going double as long as possible) after each five minutes of therapy. Computer software may be used at home or in an orthoptist's/vision therapist's office to treat convergence insufficiency. A weekly 60-minute in-office therapy visit may be prescribed. This is generally accompanied with additional in-home therapy.[4]

In 2005, the Convergence Insufficiency Treatment Trial (CITT) published two randomized clinical studies. The first, published in

asthenopic symptoms of convergence sufficiency both in adults and in children.[8] A 2020 Cochrane Review concludes that office-based vergence/accommodative therapy with home reinforcement is more effective than home-based pencil/target push-ups or home-based computer vergence/accommodative therapy for children. In adults, evidence of the effectiveness of various non-surgical interventions is less clear.[9]

Both positive fusional vergence (PFV)[10] and negative fusional vergence (NFV)[11] can be trained, and vergence training should normally include both.[12][13] 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.[1][3][2]

Prevalence

Among fifth and sixth grade children convergence insufficiency is 13%.[14] In studies that used standardized definitions of convergence insufficiency, investigators have reported a prevalence of 4.2–6% in school and clinic settings. The standard definition of convergence insufficiency is exophoria greater at near than at distance, a receded near point of convergence, and reduced convergence amplitudes at near.[4]

See also

References

  1. ^ a b "Convergence insufficiency - Symptoms and causes". Mayo Clinic. Retrieved 2022-05-26.
  2. ^ a b devora. "Does Convergence Insufficiency Impact Reading?". Optometrists.org. Retrieved 2022-05-26.
  3. ^ a b "Convergence Insufficiency | National Eye Institute". www.nei.nih.gov. Retrieved 2022-05-26.
  4. ^
    PMID 18300086
    .
  5. PMID 15642806.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  6. S2CID 9507706
    .
  7. PMC 2821445
    , NIHMSID:NIHMS153855
  8. PMC 3861273
    .
  9. PMID 33263359
    .
  10. S2CID 1634449
    .
  11. PMID 3740204
    .
  12. ISBN 978-0-7817-7784-1
    .
  13. S2CID 79967219
    .
  14. PMID 10498006
    .

External links

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