What is the condition called when the eyes move rapidly in rhythmic jerks?

The condition characterized by rapid, rhythmic movements of the eyes is known as nystagmus. This movement can be involuntary and may manifest in various forms, such as side-to-side or up-and-down motion. Nystagmus can occur for a variety of reasons, including neurological issues, inner ear problems, or as a side effect of certain medications. Understanding nystagmus is important in veterinary medicine, as it can indicate underlying health issues in animals that require further diagnostic evaluation.

In contrast, strabismus involves misalignment of the eyes, where one eye may point in a different direction than the other, affecting binocular vision. Diplopia refers to double vision, where a person sees two images of one object, which is often a result of strabismus. Amblyopia, also known as "lazy eye," is a developmental condition where one eye has reduced vision, typically due to lack of use during childhood. Each of these conditions has distinct causes and implications, but nystagmus specifically pertains to the rapid, involuntary eye movements described in the question.