Visual system disorders and musculoskeletal neck complaints: a systematic review and meta-analysis.

Accommodation disorders and nonstrabismic binocular dysfunctions affect patients' binocular system and visual performance. These visual disorders could be associated with musculoskeletal discomfort in the neck and shoulder area. The purpose of this systematic review and meta-analysis was to ascertain the relationship between visual system disorders and the musculoskeletal system of the neck. The review protocol is available in PROSPERO (CRD42018112771). All articles selected examined the relationship between neck conditions (chronic neck pain and whiplash) and the visual system in adult populations. Studies with optometric or physiotherapeutic measurements were included. Bias risk was evaluated with the modified Cochrane Collaboration Tool and Study Quality Assessment Tool. To provide complete quality assessment evidence, the authors applied the GRADEpro Guideline Development Tool. The literature search was conducted in November 2018 and yielded 745 studies among all the databases. Out of these studies, 21 were finally included. Most of the studies presented a moderate methodological quality. Only one high-quality trial was found. Based on a qualitative assessment, our systematic review and meta-analysis revealed that all included studies established a relationship between the visual system and musculoskeletal system of the neck. However, the methods for the measurement of the visual system lacked uniformity.