What question did this study set out to answer?

To evaluate whether vision training helps patients with convergence insufficiency meet Sheard's criterion.

March 21, 2026

Effect of Vision Training on Patients Who Fail Sheard's Criterion

Key Points

To evaluate whether vision training helps patients with convergence insufficiency meet Sheard's criterion.
Administered in-office and at-home vision training program to 100 patients.
Assessed patients' ability to meet Sheard's criterion post-training.
Analyzed outcomes based on additional criteria such as Percival's, symptom elimination, and stereopsis improvement.
84 out of 100 patients met Sheard's criterion after training.
Improvement was noted in symptoms and stereopsis for many patients.
Failure to meet Sheard's criterion was associated with the presence of subjective symptoms.

Abstract

Abstract One hundred convergence insufficiency patients who did not meet Sheard's criterion at near were given a program of in‐office and at‐home training. The objective was to see if they would meet Sheard's criterion after training. Results were analyzed in terms of the numbers successfully meeting this criterion as well as other criteria, i.e., Percival's, elimination of symptoms, improvement of stereopsis, and elimination of fixation disparity. Of the 100 patients, 84 successfully met Sheard's criterion after therapy. Failure to meet Sheard's criterion correlated well with having subjective symptoms.

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