Let’s see if this helps.

Some folks know that, as a fun side effect of my spinocerebellar ataxia, I have nystagmus, a condition characterized by involuntary, rapid, and repetitive eye movements—horizontal, vertical, or circular—often causing blurred vision, balance issues, and dizziness.

I’ve tried to explain what it’s like and have failed miserably. “Blurry” is wrong. “Imagine if your eyeballs jitter” only seemed to confuse people more.

Today I visited my new neuroophthalmologist and one of the tests, which was performed with an OCT (Optical Coherence Tomography) machine, gave me an idea. This isn’t exactly it (these are of a condition called oscillopsia, but it’s close enough to communicate the general idea.

This is what you see:

This is what I see:

EXCEPT: Imagine this is just one eye.

AND: Your eyes aren’t in sync. They jitter like this independently.

ALSO: The bouncing is a LOT faster. Watch this woman’s eyes closely and you’ll see the vibration (this is nystagmus):

I don’t if this helps or not, but it’s better than my explanations were before.