Good point chrisstie. I was just going to ask hybridgenius how many latz he has that are over a year and what he feeds them.
I can tell you that I fed mine mostly a homemade food mixture with various seafoods, vegetables, multivitamins, whole eggs, Selcon, Nori, etc. This was also given to my allaridi, akindynos, occ, percs., caps, GSM's, polymus, frenatus, etc. and they never went blind. Water temp. didn't seem to impact it either. Two pairs in 80's, two pairs in mid to low 70's. No visible eye injury ever and these were pretty calm fish.
I've only ever had two other fish that went blind. One white tail chrysopterus and one yellow belly blue tang.