The eye was blurry because the ray is dead. The only thing on the tail was a bit of sand.....I inspected him closely and the only strange thing I saw was a green spot on his belly. He also had a white spot from when a fish nipped him (after he was dead) on his disc.
Ive seen rays die with that green spot on the belly. Not sure if it comes after death. Or if they die cause of it. But Its only happened to my on fresh imports. May it was a parasite? Maybe from the food? What were you feeding?