Almost sounds like cloudy eye to me, but couldn't say for sure...Any chance to get a pic of the fish??? That would help tons with an ID on the problem.
You should post this question on the Marine Fish Discussion with Steve Skinner and get Steve's advice on this. I have had some success with melafix for a fuzzy dwarf lionfish, but the same med didn't help my Radiatas at all. You should go ahead and repost your question to Steve on his Forum http://www.reeffrontiers.com/forums/forumdisplay.php?f=15
Figure 20a. A P. mombasse with severely cloudy eyes. Sadly, the Mombasse lions are quite sensitive to deteriorating water quality, and are the proverbial "canary in a coal mine". These cloudy eyes can be successfully treated with an antibiotic regimen. Photo courtesy of buddamonk.