Abstract
Purpose: :
Finding a way to prevent secondary cataract formation presents a significant challenge in developing lens-based techniques to restore the accommodative ability of the human eye. The objective of the long-term animal study presented here is pharmacological intervention in polymer lens refilling surgery to prevent secondary cataract.
Methods: :
Polymer lens refilling surgery was performed on six eyes of 6 New Zealand white rabbits (age 12-15 weeks). In four eyes the empty capsular bag was treated during the surgery and after finishing phacoemulsification with an active LEC-treating viscoelastic mixture containing Actinomycin-D (AD) + D,L-Methotrexate (MTX) + Sodiumhyaluronate for 5 minutes. Ultrasound biometry, slit lamp examination, photodocumentation, and IOP measurements were performed under general anaesthesia after 1, 3, and 6 months and, for 3 years postperatively, every third month. The corneal endothelium was analysed by in vivo confocal laser scanning microscopy.
Results: :
All eyes were successfully filled using the developed surgical procedure. No complications occurred during wound healing. Without capsule treatment the first signs of opacification in the ACL rabbit eye are clearly observed 2 weeks post-op. After 6 weeks opacification was already maximal. All eyes treated with the viscoelastic AD + MTX mixture showed no posterior capsule opacification (PCO) at 12-months postop and no-to-low PCO 3 years postop. Some iris incarcerations were found in the plug area. Biometric relations pre- and postoperatively corresponded to each other, and anterior chamber depth and lens thickness were constant over the follow-up time. Shape, number, and distribution of corneal endothelial cells, and IOP, as well as the quality of fundus imaging were comparable before and after surgery. The animals (age 3.5 years) are still alive for follow up.
Conclusions: :
The lens refilling procedure is feasible in rabbit eyes without alterations in the cornea and anterior segment configuration. Without capsular bag treatment, rabbit eyes showed a strong PCO development starting directly after cataract surgery. An active LEC treatment with AD+MTX proved to be a valid method to prevent PCO in rabbits. Our findings can be seen as a good starting point from which to proceed with non-human primate studies.
Keywords: posterior capsular opacification (PCO) • accomodation • presbyopia