Are near visual signs and symptoms in multiple sclerosis compatible with convergence insufficiency?

Abstract

Clinical relevance: Optometric management of neurodegenerative diseases is essential since visual signs, such as double vision, visual acuity reduction, or oculomotricity dysfunctions, are usually present in these subjects over the course of the disease. The present paper can guide clinicians in better managing their patients with multiple sclerosis. Background: Patients with multiple sclerosis present near vision symptoms that may be related to binocular anomalies, but these symptoms have not been investigated and related to specific signs. The aim of the present study was to evaluate the binocular vision in subjects with multiple sclerosis, and to analyse if the near visual signs and symptoms observed are compatible with those found in convergence insufficiency, as occurs in other neurodegenerative diseases. Methods: A total of 57 multiple sclerosis patients and 26 healthy controls were examined and classified as potentially compatible with convergence insufficiency according to the signs and symptoms. Clinical diagnosis of convergence insufficiency was established when subjects met the following criteria: NPC breakpoint more than 6 cm, PFV ≤ than 15Δ (base-out), and exophoria greater at near than at distance at least 4Δ. Convergence Insufficiency Symptom Survey (CISS) was administered to assess the symptomatology considering a score ≥16 as positive. Results: According to the CISS score, 54,4% of the multiple sclerosis subjects revised showed a suspect of convergence insufficiency, with a median score of 27 (IQR 9), whereas only one subject from control group (3.8%) showed this suspect. According to the diagnostic criteria based on signs, only 15.8% of multiple sclerosis patients had a real diagnosis of convergence insufficiency. Conclusion: Multiple sclerosis patients showed symptomatology compatible with convergence insufficiency, but this was not supported by the signs which showed a more esophoric tendency. The discrepancies between the signs and symptoms could be due to the questionnaire used including items that are also related to the cognitive function and other ocular abnormalities.