Optimal folding axis for acrylic intraocular lenses.

Acrylic intraocular lenses (IOLs) are easier to insert than foldable lenses of other materials. In addition to material properties, the structure of acrylic lenses allows an optimal folding angle along the 10 to 4 o'clock axis. Folding the IOL along this axis simplifies the manipulation of the leading haptic during insertion and places the trailing haptic within the capsular bag before the folded optic is released.