Final answer:
Internuclear ophthalmoplegia is an eye movement disorder that may be present in patients with Friedreich ataxia, causing double vision.
Step-by-step explanation:
Friedreich ataxia is a genetic disorder that affects the nervous system, specifically the cerebellum. One eye movement disorder that may be present in patients with Friedreich ataxia is internuclear ophthalmoplegia. This is characterized by the failure of one eye to abduct while the other adducts during horizontal movement, resulting in double vision (diplopia).