I saw this question arise recently in an online community.
Personally I wouldn’t mention it straight away, I don’t think it’s important. I remember receiving some advice once of a lady who shared her thoughts and she pointed out that if you share any condition you have, you are only putting yourself down, or bringing unwanted attention to an issue that shouldn’t be an issue.
Don’t mention it, unless it’s raised.
When I’ve been on dates and my date has said “oh your eyes move?” - I’ve simply followed up by stating:
“Yeah they do that, they dance around a bit, it’s an eye condition that I have”.
People ask because they are curious and usually have no bad intentions. It’s not something that should impact your relationship and if it does, the person is likely shallow.