Prism Prescription in Strabismic and Non-Strabismic Cases

This systematic review investigates the clinical effectiveness, prescription techniques, outcomes, and complications associated with prism therapy in both strabismic and non-strabismic binocular vision disorders. Prism lenses remain a key non-invasive intervention for managing ocular misalignment and vergence anomalies, but clinical variability in application and outcomes necessitates a comprehensive synthesis of current evidence. A systematic search was conducted across PubMed, Embase, Cochrane Library, Scopus, and Google Scholar for studies published between January 1990 and June 2025. Inclusion criteria encompassed randomized controlled trials, observational studies, and case series evaluating prism use in strabismic or non-strabismic patients. A total of 498 records were identified, with 38 studies meeting all inclusion criteria. Data extraction and quality assessment were conducted using standardized forms, and risk of bias was evaluated with the Cochrane Risk of Bias Tool and Newcastle–Ottawa Scale. Prism therapy in strabismic cases demonstrated effectiveness in alleviating diplopia, improving fusion, and providing cosmetic alignment in patients with small, comitant deviations. Fresnel and ground-in prisms were commonly employed. In non-strabismic cases, particularly convergence insufficiency and vertical phoria, prisms effectively reduced symptoms such as eye strain, blurred vision, and difficulty with near work. However, outcomes varied with dosage, adaptation, and patient compliance. Complications such as prism adaptation, diplopia persistence, and suppression were noted across both populations. Prism therapy is effective in selected strabismic and non-strabismic cases when guided by appropriate clinical evaluation and patient selection. The evidence supports conservative, individualized prescription practices with close monitoring. Further highquality trials are needed to establish standardized protocols and long-term outcome data for prism use in diverse patient populations.