Decentration associated with asymmetric capsular shrinkage and intraocular lens size.

An intraocular lens (IOL) may become displaced even when it has been implanted in the capsular bag. Asymmetric capsular shrinkage is one cause of lens decentration. To determine whether the IOL length influences the degree of decentration, we assessed the decentration of IOLs of different lengths in rabbits. After a D-shaped anterior capsulotomy that covered about half the area of an ordinary circular capsulotomy was performed in 19 eyes of ten white rabbits, a 14.0 mm IOL was fixated in the bag in one eye and a 12.5 mm IOL in the other eye. A circular anterior capsulotomy was performed in 16 eyes of eight controls and IOLs were similarly placed in the bag. Decentration of the 14.0 mm and 12.5 mm IOLs in the eyes with the D-shaped anterior capsulotomy did not differ eight weeks after the procedure. However, marked rotation from the initial position and decentration to the side opposite to that expected were observed in some eyes in which nodular opacification was observed. Both the 14.0 mm and 12.5 mm IOLs were markedly more displaced in eyes with the D-shaped anterior capsulotomy than in eyes with the circular anterior capsulotomy. These results confirm that asymmetric capsular shrinkage, which is affected by the anterior capsulotomy shape, influences post-operative IOL centration.