The dress code for ARVO is casual, even when you are lecturing. One of the aims of the meeting is to foster communication among vision scientists in a casual atmosphere. Because the meeting is in Florida, most people will probably wear shorts and sandals. The one problem with that is that although the weather is hot and sunny outside, the air conditioning in the convention center is on high the entire week. Bring layers so that you can keep up with the changing “weather” conditions.
I have seen people lecture in wet bathing suits in the past, although I wouldn’t recommend it. Shorts (or light pants) and a nice shirt are typical. Ties are practically forbidden.
There is no better opportunity to meet friends/colleagues/collaborators in a casual setting. Take advantage of it!
See you at ARVO!
–Jeff