What is Nystagmus?

Nystagmus is characterized by uncontrolled, repetitive movements of the eyes. These movements can occur in a variety of patterns, including side to side, up and down, or in a circular motion. This condition can affect balance and coordination, as it often results from issues in the vestibular system or neurological problems.

The other options describe different conditions or terms associated with eye movement or vision that do not align with the definition of nystagmus. For example, a fixed position of the eyes doesn't involve any movement, while cross-eyed refers to strabismus, a misalignment of the eyes that can cause each eye to point in a different direction. Temporary blindness is not a movement condition but rather a loss of vision. Thus, the involuntary movement described in the correct answer is the defining characteristic of nystagmus, clearly distinguishing it from the other choices.