New photochromic foldable intraocular lens: preliminary study of feasibility and biocompatibility.

PURPOSE: To evaluate a new hydrophobic acrylic intraocular lens (IOL) with photochromic properties in vitro and in vivo in a rabbit model.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

METHODS

The photochromic optic change of 5 study IOLs was evaluated in vitro on ultraviolet (UV) light exposure. The tests were done in the dry state and during immersion of the lenses in a balanced salt solution. Six additional IOLs were implanted in the right eye of New Zealand rabbits. The left eyes were implanted with SA60AT or SN60AT IOLs (Alcon Laboratories, 3 each). After a clinical follow-up of 6 months, the rabbits were killed and their eyes enucleated. Three study IOLs and 2 control SN60AT IOLs were evaluated in vitro on UV exposure after explantation. The other IOLs and the rabbit eyes had histopathologic examination.

RESULTS

On in vitro UV light exposure, the optic of the study IOLs changed from colorless to yellow, turning again colorless on discontinuation of UV light projection. The same photochromic change was also observed on UV light exposure throughout the clinical follow-up of 6 rabbits, as well as after explantation of the IOLs. Postoperative clinical inflammatory reactions and cellular reactions on the surface of the explanted IOLs were similar in the study and control groups. No sign of untoward toxicity was observed in the histopathological sections of the rabbit eyes in all groups.

CONCLUSIONS

The new photochromic IOL turned yellow only on exposure to UV light; otherwise it remained clear. This lens was also found to be biocompatible.