A transparent double convex (outward curve on both sides) structure between the iris and the vitreous humor. Two structures of the eye focus light onto the retina. The first is the cornea or front surface of the eye that provides about 65% of the focusing power of the eye. The human lens is located behind the iris and in front of the vitreous humour and provides the remaining focusing power for the eye. In younger patients (usually below age 45) the lens is able to adjust it's power allowing the eye to change it's focal length from distance to near.