A case study of choroideremia highlighting differential diagnosis and management with Fresnel prism therapy

Choroideremia, along with other choroidal and retinal dystrophies, produces a progressive peripheral visual field loss. This paper highlights how to approach the optometric evaluation of a field constricted patient, how to decide if Fresnel prism therapy is appropriate and how to manage the patient if it is.

The patient described in this case report is a 36-year-old white male who presented with a diagnosis of choroideremia. On examination, the patient was found to have visual acuity of 20/40 OD and 20/30 OS. His visual fields by Goldmann perimetry were 8 degrees OD and 10 degrees OS. Treatment and management included the fitting of Fresnel prisms.

The Fresnel prisms were utilized to successfully displace the images of objects toward the patient's central seeing visual field and to eliminate the excessive head turns that were often employed to enable him to view peripheral objects.

Many patients with constricted visual fields can be successfully managed with the use of Fresnel prisms.