YAG capsulotomy: A laser technique to correct blurred vision caused by cloudiness that may develop in the skin of the cataract left in the eye after cataract surgery; a laser is used to create a hole in the membrane to allow light to enter clearly focused onto the retina.

yohimbine: An extract of the bark of a West African tree sometimes used in treating erectile dysfunction. Yohimbine appears to increase blood flow to the penis and prevent blood from leaving it too quickly.