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.
Emeralds can also be found in Villages, as they are the main currency used in the Villager trading system, replacing the Ruby, an item found in older versions of Minecraft. Emeralds can rarely be found in the chests of Desert and Jungle Temples, similarly to many other ore materials.