Abstract
Purpose:
Complete removal of lens epithelial cells (LEC) is a strategy to prevent posterior capsule opacification, the major complication of cataract surgery. Intraocular lens (IOL) stability within the capsular bag is important to good visual outcome. We therefore investigated how total LEC loss affects IOL stability within the capsular bag.
Methods:
Capsular bags were generated from human donor eyes by capsulorhexis and lens extraction followed by implantation of a single piece Acrysof IOL. Capsular bags with associated zonules and ciliary body were removed from the eye and secured by pinning the ciliary body to a silicone ring. Capsular bags were maintained in 6ml EMEM supplemented with 5%FCS and 10ng/ml TGFβ2 for ≥ 3 weeks. One bag of each pair was treated with 1µM thapsigargin, a calcium ATPase inhibitor; this was employed to destroy all LECs. Observations of LEC growth were captured by phase contrast microscopy. IOL stability within the bag was assessed by video microscopy. At end-point the bags were examined using scanning electron microscopy (SEM) and immunocytochemistry.
Results:
LECs in control capsular bags could be observed to migrate centrally closing the bag and fixating the IOL between the anterior and posterior capsules, as seen clinically. In addition a firm seal was formed at the rhexis edge between the anterior capsule and the underlying IOL. Application of thapsigargin to the capsular bags prevented cell growth and led to a complete loss of viable cells. Consequently, thapsigargin treated preparations did not exhibit adhesion between anterior and posterior capsules nor adhesion to the IOL surface. At end point these observations were confirmed by SEM and immunocytochemistry. Following a period of controlled orbital movement, the positioning within the capsular bag was unaffected in each test group. However, the IOL in the control group stabilized quicker than in the thapsigargin treated bags.
Conclusions:
LECs appear to aid stabilization of current IOL designs in the capsular bag. This study has important clinical implications for IOL design and for strategies to prevent posterior capsule opacification.
Keywords: 445 cataract •
567 intraocular lens •
652 posterior capsular opacification (PCO)