Clinical profiles of binocular vision disorders and the efficacy of prism-vergence therapy in management of diplopia

Background: Binocular vision disorders (BVDs), encompassing both strabismic and non-strabismic entities, are a frequent cause of diplopia and visual discomfort. Evidence on the clinical spectrum of BVDs and the therapeutic benefit of combining prism correction with vergence therapy remains limited.Aim: To assess the clinical profile of strabismic and non-strabismic BVDs and to evaluate the effectiveness of combined prism correction and vergence therapy in patients presenting with diplopia.Materials and Methods: This study comprised two arms. The retrospective arm included 513 patients aged 6–60 years who attended a Binocular Vision Therapy Clinic between March 2024 and February 2025. All patients underwent comprehensive sensory-motor evaluation, including ocular alignment, fusional vergence, and accommodative function testing. The prospective interventional arm included 66 symptomatic diplopia patients treated with prism correction combined with home-based or office-based vergence therapy. Outcome measures included ocular alignment (prism diopters), sensory fusion, stereoacuity, and prism dependence.Results: A total of 579 patients were evaluated. In the retrospective cohort, non-strabismic BVDs accounted for 60.2% of cases, while strabismic BVDs constituted 39.8%. Convergence insufficiency (19.7%) and accommodative insufficiency (11%) were the most common non-strabismic disorders. In the interventional group, 88.7% achieved motor and sensory fusion following combined therapy, with a statistically significant improvement in sensory fusion (p = 0.048). Complete discontinuation of prism use was achieved in 32.4% of patients, and 23.9% demonstrated reduced prism dependence. Home-based therapy was employed in 81.7% of cases.Conclusion: Non-strabismic BVDs are more prevalent in vision therapy clinics. Combined prism correction and vergence therapy is highly effective in managing diplopia, improving fusion and alignment while reducing long-term prism dependence. A structured, individualized binocular vision therapy protocol provides optimal outcomes in both strabismic and non-strabismic cases.