The role of capsulotomy and intraocular lens type on tilt and decentration of polymethylmethacrylate and foldable acrylic lenses.

The purpose of this study is to determine the effects of different anterior capsulotomy techniques and intraocular lens (IOL) types on IOL tilt and decentration. For this purpose the device using Purkinje reflections and photographic documentation were evaluated. A total of 107 cataractous eyes undergoing IOL implant surgery were divided into four groups based on the type of IOL and capsulotomy: group 1, single-piece polymethylmethacrylate (PMMA) IOL with a haptic distance of 13.50 mm; group 2, single-piece PMMA IOL with 12. 0 mm overall length; group 3, three-piece foldable acrylic IOL with 13.00 mm PMMA haptic distance; group 4, the same IOL as group 1. While continuous circular capsulorhexis was the type of capsulotomy in the first three groups, envelope capsulotomy was used in group 4. Mean tilt and decentration were significantly less when capsulorhexis technique was used in comparison with envelope capsulotomy. Mean tilt of group 1 (2.83+/-0.89 degrees) and mean decentration of group 2 (0.28+/-0.14 mm) were higher within the first three groups. The differences regarding both the IOL decentration and tilt between the first three groups were statistically significant. This study shows that if the IOLs were placed properly in the capsular bag after continuous circular capsulorhexis, foldable acrylic IOLs with PMMA haptics are superior in terms of tilt and decentration.