Prism Success in Patients with Diplopia and Retinal Pathology

Purpose: To evaluate the effectiveness of prisms in treating binocular diplopia in patients with retinal pathologies and to evaluate factors associated with treatment success. Methods: A retrospective chart review was conducted on patients ≥ 18 years with binocular diplopia and retinal pathology presenting between 2012– 2022. Patients prescribed prisms with ≥ 1 follow-up were included. Subjective prism prescriptions were compared to measured deviations. Associations between treatment success and clinical factors were analyzed. Results: Seventy patients (mean age 73.5 ± 8.6 years) were included, most with epiretinal membranes (54.3%) or prior retinal detachment (14.3%). Diplopia was eliminated in 65.7% of patients with prisms, though 43.5% of these patients required at least 1 prism change. For horizontal deviations, prescribed prisms were lower than measured deviations at both distance (Mean = 3.39 ± 4.23 PD vs. 5.33 ± 6.03 PD, p < 0.001) and near (Mean =1.99 ± 2.35 PD vs. 4.30 ± 6.05 PD, p =0.005). Vertical prism prescriptions were similar to measured deviations at distance (Mean = 2.34 ± 2.96 PD vs. 2.04 ± 2.37 PD, p =0.128), but higher at near (Mean = 1.99 ± 2.35 PD vs. 1.26 ± 2.47 PD, p =0.006). No significant associations were found between treatment success and type of retinal pathology, visual acuity, age, or prism type (Fresnel or ground-in) (all p > 0.05). Conclusion: Prisms effectively eliminated diplopia in most patients, though adjustments were frequently necessary. Discrepancies between measured and subjectively preferred prism magnitudes highlight the importance of careful, individualized prism trials.