Traumatic optic neuropathy (TON) refers to an acute injury of the optic nerve secondary to trauma. The optic nerve axons may be damaged either directly or indirectly and the visual loss may be partial or complete.
In Minecraft, emerald ore is very hard to find and is found in small deposits in the Extreme Hills biome. You can usually find emerald ore between 13 and 31 blocks below the ground and close to lava. So if you see a pool of lava in the Extreme Hills biome, that is a great place to start mining downward.
Inspect the gem's color. A true emerald is deep green. Stones of a lighter hue are likely not emeralds at all, but green beryl. There are no guidelines, however, and jewelers and gem labs can sell green beryl as emerald. A true emerald will be darker than a glass Coke bottle.