"Special" intraocular lens designs: why do they sometimes fail?

A variety of new "special" intraocular lens models to optimize the visual performance after cataract surgery have been introduced. The majority of these new intraocular lens designs require a good centration within the capsular bag and/or capsular elasticity. Today, the main post-operative complications after cataract surgery still arise from retained lens epithelial cells within the capsular bag, resulting mainly in anterior and posterior capsule opacification. Some special intraocular lenses are not designed to be effective against proliferating lens epithelial cells. Although lens epithelial cells can never be completely removed from the capsular bag, surgical quality is a major factor for success or failure of these intraocular lens designs.