Help With discus eye Desease

[Nadine]

I need help, this morning noticed that discuses in one of my two tanks are developing cloudiness on their eyes, some of then are having an opaque white circle covering the middle of their eyes (on the lenses I guess) and some have the circle opaque on the edges and cloudy in the middle. I have 7 fishes in this tank and all except 2 got struck with this desease in different degrees. But no sign of any other desease, the fish is active, they ate and are not turning dark
The fishes are all adults, the water temp is a steady 85F and I have not added any new fish or plants recently, I feed them Frozen BW.
Can somebody help, is it Bacterial or fugal? How should I treat it and am'I going to loose any fish over that, is the fish going to become blind?
Thank you in advance for your responses.
:cry:

[Merrilyn]

Have you checked your pH lately ?

A sudden drop in pH can do that to eyes.

How often are you doing water changes, and what percentage of the tank do you change.

[Nadine]

1/3 of the tank water change every 2 days or so, i have not checked the PH . I will.