Odontodactylus Scyllarus going blind?
 

So recently I noticed my O.scyllarus acting odd. He roams around the tank non stop, very active, which I know doesn't sound too bad and at first I thought he was just finding materials for an upcoming molt..

Then I tried waving my hand infront of the glass just to get his attention and noticed that he payed no mind to me. Infact he just ignores me entirely whenever I wiggle my finger or anything. Something didn't seem right, so I then decided to clean the glass, and noticed he didn't even pay mind to the blade, the thing usually they go ape**** when they see. Infact he was just walking around as if nothing was going on as I finished cleaning.

Then I decided to feed him some raw shrimp, and normally he would just take it, run and eat it.. instead it floated in his face twice, he ignores it and continues running around like a headless chicken looking for it, and then eventually he finds it, and attacks it as if he's making sure its dead and can't see for himself.

He's only like 4-5 inchs, I actually didn't keep a light on his setup at all, had him for almost a year now and no molt yet. His eyes are moving, but they don't seem to be seeing anything, when I look into them they seem fine and clear.

What causes this?