Ok, first let me say, that a fish with creamy/white/cloudy eyes, is never a good sign. This is especially true when your fish has already suffered an injury, and the discoloration (cloudiness), has only developed afterwards. From the information you gave me, I have a few ideas as to what might have happened since the injury. But before I go on, I just need to clarify something -- you did remove your injured Oscar from the main tank into an isolation tank right? I hope so. And he/she is still in isolation right?? Please tell me you did not put him/her back into the main tank!??! If you did, move him/her back to islotaion imediatly!
OK- got that off my chest!
Moving on.............
The first of a few things that came to mind, was pop-eye. Now most of the time people associate this ailment solely with bulging eyes, as that is the most apparent of the disease. However, just because the eyes may not have bulged too extreme, I wouldn't check it off the list just yet. The reason I bring this disease up at all, is because POP-EYE, or Exophthalmia, is a symptom more than a disease in its self, and there is a viriety of things that could trigger this symptom. For instance; not enough water changes, resulting in build up of feces and decaying matter (though this should not apply, as you said you have kept up the water changes), Ichthyophonus ( this is different from Ichthyophthirius, which cause Ich/white spot disease), it is a cataract disease, which often leads to blindness. Also Ichthyosporidium (again, different from "ICH"), this strain is a parasitic fungus. Another "cause" related with pop-eye, is a secondary bacterial infection, parasitic infections caused by eye flukes, or simply metabolic disorders. Most of these "causes" probably do not play a role in your current situation, however, eye flukes may, thus being the reason i even mention pop-eye. Your fish may not have it now, and in truth, may not even develop pop-eye, but if your fish has contracted an infestation of eye flukes (which could be the cause for the hole in your fish's eye), then this is a secondary condition you are going to need to watch out for.
As far as the actual cause of the whiteness to the eye, my guess would be "cloudy eye", which once again, this is most likely a secondary infection (symptom). Usually it is cause by severe stress or trauma to the eyes (which we already know happened). Usually, when a fish develops this condition, if removed from the source of stress/aggression, it will clear in a few days on its own. The problem with this condition however, is that it is most often seen when there has been irritation to the eye (once again, we know this happened), and because of that, the eye becomes more vulnerable to bacterial/fungal infections. Not to mention that sight is obviously impaired, so any obstructions in the tank, can cause even more damage to the infected eye from the fish not being able to see clearly and bump into things. As far as treatment for this condition, I wouldn't suggest, nor deny any medications. Usually, it doesn't require anything other than the fish being in a peaceful, safe area, with great water quality.
Flukes affect the gills and skin of the fish, but can also infect the eyes, especially where an injury is present. Oscars and other big types of cichlids are extremly susseptible to these parasites. If left untreated, they can cause severe secondary infections, and result in total loss of the eye, and may spread (if haven't already) to the rest of the body, spelling disaster.
Its hard to say exactly, without having a picture to refference, but so far, I would say these could be some things you may be dealing with, or may soon see. If you could, please take some pictures of the infected areas so that I can have a visual. Without photos, I am only left to guess from your description. I hope some of this was of some help though, and would be happy to provide more info once you got a picture. I am also going to contact zoodiver, as he may also have some things to add to this ok. Don't stress, and don't stress the fish any more than absolutly necessary.
As far as aquatic vets in your area, I would first suggest checking out the website to the Montreal University at
www.medvet.umontreal.ca They have a ton of information pertaining to aquatic studies and so forth. From there, I would suggest contacting the marine directors and asking for referrals to local aquatic vets in your area. They may even have some available to the public right on campus. If you are within driving distance to the campus, I would suggest going there in person -- you always get better help in person, instead of the run-around on the phone, or via e-mail. So check it out, post a pic. and keep me posted to any changes, good or bad. talk to you soon.
--Emi
