Popeye, also known as exophthalmos or exophthalmia, is more a condition than it is a disease. In saltwater fish it may affect one or both eyes, appearing as if the eye has air or fluid trapped inside, around or behind it, causing the eye to enlarge and bulge out of its socket, as if under pressure. Duration of this condition can be anywhere from several days to several weeks.
http://saltaquarium.about.com/cs/com...a/aa053001.htm
Richard