sorry i missed the play date
was Romeo playing alot (or doing what he did the last time *snort*)? maybe another dog got him in the eye? can you open the eye? do you see a scratch or anything in it? if you have saline you can flush the eye to see if maybe he just got alittle something in it.
if its still a problem in the morning, i'd take him to teh vet. he might have a scratch on his cornea.