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The „Add-On” principle is the procedure of implanting a second intraocular lens in front of another one into one eye.

Conventional, primary IOLs are usually implanted into the capsular bag (4), the place where the natural lens is located before it is removed by cataract surgery. The Add-On lens is implanted into the sulcus ciliaris (3) in addition to the IOL already in the capsular bag. The sulcus ciliaris is the area that stretches across from behind the iris to the capsular bag, the original place of the natural lens.

Add-On IOLs have a special design. So they are a little lager than conventional IOLs, to ensure safe and secure fixation.

After surgery the patient will not feel the implant and it will not be visible to others. Both lenses should remain problem-free in the eye permanently. The first Add-On IOL was successfully implanted back in the year 2000.




The modern method to implant two IOLs into one eye may be reasonable in various situations.
Mainly Add-On IOLs are used to correct visual errors like myopia, hyperopia or astigmatism that remain after a cataract operation. Therefore visual performance is improved and patients are free from spectacles or contact lenses for far vision in daily life.

With the Diffractiva® Add-On model spectacle independence additionally for near distance is possible. Therefore the advantages of multifocal IOLs are also available for patients who already had a cataract procedure performed before multifocal IOL technology was available. It is surgically a lot easier and less traumatic to add an Add-On lens than to remove and replace a primary pre-existing lens, which is a big advantage of this system.

In contrast to visual corrections by laser (LASIK, etc.) no natural corneal tissue is ablated by correction using Add-On lenses. The eye’s cornea remains untouched apart from a small (and immediately self-sealing) incision of a few millimeters at the corneal rim. As no tissue is ablated the procedure is reversible and the Add-On lens can be removed any time.

The Add-On procedure is suitable at any time after cataract surgery, even if the previous cataract treatment dates back some years.

In cases where the cataract surgery is yet to be performed it may also be beneficial in some cases to implant two separate lenses during the one procedure into the eye – the capsular bag IOL and the additional Add-On lens. For example such could be the case with very high visual errors requiring high powers to maintain thin and foldable IOLs by splitting the power into two separate, thinner IOLs whose power add up again in the eye.
For further information regarding when and why this procedure might be suitable please contact your surgeon directly, as various different factors can affect this. Generally it can be said that your surgeon is given a variety of options, which assist him to treat every patient individually for the best possible outcome.