Convergence insufficiency (CI) is an exodeviation that is greater at near fixation than at distance fixation. It is characterized by poor fusional convergence amplitudes and a remote near point of convergence (normal fusional vergence amplitudes are given in Chapter 7, Table 7-1). This sometimes results in symptoms of asthenopia, blurred near vision, and diplopia during near work, usually in older children or adults. Convergence insufficiency is a common complication of Parkinson disease. Rarely, accommodative spasms occur when accommodation and convergence are stimulated in an effort to overcome the CI.
Treatment of symptomatic CI typically involves orthoptic exercises. Base-out prisms can be used to stimulate and strengthen fusional convergence amplitudes. Stereograms, “pencil push-ups,” and computer-based or office-based convergence training programs are all viable options. If these exercises fail, base-in prism reading glasses may alleviate symptoms. Surgical treatment, usually medial rectus muscle resection, may be indicated in patients whose problems persist despite medical therapy.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.