Which statement BEST defines nystagmus?

Which statement BEST defines nystagmus?

• A. Eye swollen shut
• B. Inability of the pupil to accommodate to light
• C. Involuntary lateral movement of eye
• D. Rapid decrease in visual activity

Answer: (C)

Nystagmus is the involuntary, rhythmic movement of the eyes. This movement can be horizontal, vertical, or rotary, and it persists despite trying to fixate on a target. The statement describing an involuntary lateral movement of the eye best captures this definition because it directly refers to the characteristic eye movement that defines nystagmus. The other options describe different eye or vision problems. Eyelid swelling refers to edema or trauma affecting the eyelids, not the eye movement itself. Difficulty with the pupil's ability to accommodate to light points to a pupillary or focusing issue rather than a rhythmic eye motion. A rapid decrease in visual activity describes sudden vision loss, which again is a different problem than nystagmus. In athletic care, spotting nystagmus can indicate vestibulo-ocular or neurological involvement, such as concussion, and prompts further assessment.

Nystagmus is the involuntary, rhythmic movement of the eyes. This movement can be horizontal, vertical, or rotary, and it persists despite trying to fixate on a target. The statement describing an involuntary lateral movement of the eye best captures this definition because it directly refers to the characteristic eye movement that defines nystagmus.

The other options describe different eye or vision problems. Eyelid swelling refers to edema or trauma affecting the eyelids, not the eye movement itself. Difficulty with the pupil's ability to accommodate to light points to a pupillary or focusing issue rather than a rhythmic eye motion. A rapid decrease in visual activity describes sudden vision loss, which again is a different problem than nystagmus. In athletic care, spotting nystagmus can indicate vestibulo-ocular or neurological involvement, such as concussion, and prompts further assessment.