It is not a magic item, but a magic-imbued object.
This is the eye of a Silver Dragon Wyrmling.
A ritual, similar to Gentle Repose, has preserved this eye and caused the dragon’s own natural ocular properties to temporarily lie dormant.
Should the eye be inserted into another’s eye socket successfully, over time the Drake’s Eye’s nerve endings will attach to it’s host, as the host will become permanently attuned to the Drake’s Eye. This attunement grants the host 15 ft blindsight, as well as 60 ft darkvision. Once per day the host can make use of the dragon’s legendary capabilities to automatically succeed on a perception check (to notice the subtlest shift in the air as the invisible monster makes for the exit; to spot the fine wire running at the base of the open doorway; etc.).
It is recommended to cover the Drake’s Eye with a cloth strip, or an eyepatch for a period of time after it has been inserted into the new host’s eye socket. This will cause problems with depth perception (eg. disadvantage on Wisdom (Perception) checks that rely on sight, as well as disadvantage on ranged attack rolls, etc.) however, should the host be exposed to a very bright light (eg. daylight spell) or an effect that would blind them before the Drake’s Eye has attached itself to the host, the Drake’s Eye could become permanently blinded.