1612: Regulation of Inflammation to Prevent Cataract Surgery Complications

Project Summary

Cataracts are a progressive change to the lens of the eye, resulting in cloudiness and interference with vision. Cataracts are the most common cause of blindness in dogs. Surgery and placement of an intraocular lens implant (IOL) can restore normal vision. Although every effort is made to remove as much lens material as possible during cataract surgery, it is inevitable that some lens cells remain. These cells will migrate and proliferate, resulting in the most common complication to surgery, posterior capsule opacification (PCO). PCO interferes with light transmission and results in secondary vision loss. Cataracts occur in all breeds and PCO occurs in 100% of canine post-operative patients. Unfortunately, there is no consistently effective treatment for canine PCO. Studies performed by us and others, have found that use of a commonly prescribed drug, Cyclosporine A (CsA) can decrease PCO formation and decrease post-operative inflammation. We believe that CsA may provide a safe and reliable option to prevent PCO in dogs. In a laboratory setting, we have concluded that because standard IOLs can only delivery substantial doses of drug for 24 hours and 5 days of drug delivery is needed to prevent PCO formation, commercially available IOLs are not an ideal way to deliver CsA inside the eye. We are working on characterization of a new biocompatible, biodegradable, injectable, and inert composite to be placed within the lens capsule following surgery. We have shown this composite has a good solid-to-gel transition that allows the compound to be injected during cataract surgery but remain within the capsule for extended periods of time postoperatively. We have successfully synthesized the gel in the laboratory and will continue examining the properties of the gel and its drug delivery capabilities. The second goal of our study was to evaluate the potential toxicity of CsA to other tissues within the eye. Our studies have shown that CsA exposure does not cause overt damage to the vulnerable corneal endothelial cells. We are continuing to build evidence that extended release of CsA will be safe for use inside the eye. This study supports the use of controlled release of CsA following cataract surgery, giving veterinary ophthalmologists a new method of restoring excellent long-term vision in dogs that have been blinded by cataracts.

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