Prism Success in Patients with Diplopia and Retinal Pathology

To evaluate the effectiveness of prisms in treating binocular diplopia in patients with retinal pathologies and to evaluate factors associated with treatment success.

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.

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).

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.