Prism Use in Adult Diplopia

Kammi B. Gunton; A'sha Brown


Curr Opin Ophthalmol. 2012;23(5):400-404. 

In This Article

Abstract and Introduction


Purpose of review: Prismatic correction to restore binocularity in adult diplopia can be challenging. This review summarizes the results of prismatic correction in adults based on the cause of diplopia.
Recent findings: Satisfaction with prismatic correction is achieved in approximately 80% of all adult patients with diplopia when combining the causes. Of patients with vertical diplopia, skew deviation and fourth nerve palsy have the highest satisfaction rates, 100 and 92%, respectively. Patients with thyroid eye disease and orbital blowout fractures associated with diplopia had the lowest satisfaction rates, 55 and 8%, respectively. With regard to horizontal deviations, patients with decompensated childhood strabismus with a combination of horizontal and vertical deviations and patients with convergence insufficiency had the lowest satisfaction rates, 71 and 50%, respectively.
Summary: Careful selection of patients for prismatic correction, management of patient's expectations, and continued follow-up to monitor the symptoms are critical to the successful use of prisms.


Adults with symptomatic diplopia often have severe functional disability. Patients with adult-onset strabismus lack the ability to create suppression scotomas to adapt to their deviation, thereby creating constant diplopia. The deviations may be incomitant with diplopia only in certain gazes. The deviations may be large and exceed normal fusional vergences. Restoring functional binocularity is critical for these patients. Binocularity may be achieved with a variety of treatment options including traditional ground-in prisms, Fresnel prisms, eye muscle surgery, occlusion, or a combination of these options. Resolution of diplopia in the primary position is usually considered the successful treatment. Secondarily, diplopia in downgaze needs to be addressed to restore functionality for reading. Patient expectations of treatment need to be addressed early in diplopia management.

The most appropriate treatment for a patient is selected with consideration of various factors including the cause of the diplopia, severity of symptoms, overall patient health, and cost considerations. Prisms correct strabismus by altering the pathway of light, moving images onto the fovea of the deviated eye or within a range to allow fusion of the images if possible. Prisms can be ground into spectacle lenses or a Fresnel prism can be applied. In general, prisms are considered effective for small, comitant deviations. Data is emerging for their use in larger and incomitant deviations as well. Prisms have also been used for the relief of symptoms in decompensated phorias and long-standing strabismus of childhood.

This article reviews the results of prism use in adult diplopia secondary to common causes. This includes vertical deviations secondary to fourth nerve palsy, thyroid eye disease, skew deviation, and blowout fracture as well as horizontal deviations secondary to sixth nerve palsy, decompensated phoria, divergence insufficiency, and convergence insufficiency.