What is a multi-piece IOL lens and what’s the use of it?

Intraocular lens implants (IOLs) are what are used to replace the aging, discolored natural lens. These are typically a smaller diameter and thinner than the natural lens they are to replace, so there is usually a pair of "feet" or haptics on either side that secure the IOL within the clear, cellophane-like envelope that once held the natural lens (called the "capsule").

An otherwise identical IOL can be selected in either a 3-piece or one piece version. The latter are easier and cheaper to manufacture so are largely replacing the former. However, a 3-piece IOL is more versatile in that it can be implanted not only within the capsule (the envelope) but in front of it as well, against the back of the iris. This is useful in situations where there may not be an intact capsule sufficient to hold an IOL securely. One piece IOLs often have square-edged haptics that can chafe and irritate the iris, so can only be used safely if there is an intact capsule.

_Written by J. Trevor Woodhams, M.D. - Chief of Surgery, Woodhams Eye Clinic