An undine is an ophthalmic irrigation device which was used to trickle a cleansing liquid over the conjunctival surface while controlling the flow with the thumb or finger over the filling hole. It has now been superseded by more modern equipment.[1] [2]
The undine is a spherical or pear-shaped glass flask generally about 2 to 3 inches in diameter with a 2 to 3-inch narrowing spout on one side and a collared opening on the top about half an inch wide.[3]
They were used predominantly from the 1930s to the 1960s after which single-use plastic disposable equivalents became available.[4] As glass undines require careful cleaning and sterilization after each use, single-use plastic equivalents were preferred as they are cheaper and require no careful handling.