Inconsistent diagnostic criteria for convergence insufficiency

Convergence insufficiency (CI) is a common entity but seems to be an ill-defined diagnosis that incorporates many near-vision symptoms. The current literature often varies in its criteria for diagnosis. Without a clear definition and standardization of the clinical examination, there is the potential for misdiagnosis and/or the inclusion of other diagnoses as CI. The purpose of this study was to assess the uniformity of diagnostic criteria in a well-defined practice environment.

The medical records of individuals diagnosed with CI between June 2007 and November 2014 who were patients of 6 fellowship-trained strabismologists in private practices and at Wills Eye Hospital clinics were reviewed retrospectively. Exclusion criteria included any previous treatments for CI, prior strabismus surgery, or other causes for strabismus, including cranial nerve palsies. The following data were collected: age, sex, race, age at diagnosis, past medical and family history, relevant symptoms, visual acuity, near point of convergence (NPC), strabismus measurements, and fusional amplitudes at distance with base-out and base-in prisms.

A total of 387 patients fit our inclusion criteria and were analyzed in our study. There was no uniformity across clinicians in the clinical evaluation and diagnosis of patients with CI. The amplitude of the NPC was highly variable, and most clinicians did not assess the quality of the convergence movement or perform convergence fusional amplitude testing in making the diagnosis of CI.

Our review has demonstrated the range of criteria within one group of practitioners to diagnose CI. This may reflect our current understanding and the need for an evidence-based definition of the disease and its diagnosis.