Grant: Collaborative Health Research Projects (NSERC partnered)

"MEDICAL PROBLEM: Glaucoma, a degenerative disease of the optic nerve, is the leading cause of irreversible blindness in the world. In Canada alone, over 11,000 glaucoma operations are performed each year. A major limitation of current glaucoma surgery is the inablility to precisely adjust the amount of intraocular pressure (IOP) post-operatively. IOP must be lowered as precisely as possible because an IOP that is lowered excessively can lead to blinding complications. Traditional 'trabeculectomy' surgery involves the creation of a scleral flap (a guarding trap door of tissue) and a small opening (fistula) to permit fluid egress from the eye's rigid corneo-scleral layers. This fluid is then captured under the mucus membrane layer of the eye called the conjunctiva, and reabsorbed by the body. The scleral flap is secured with standard sutures; however, precisely gauging the suture tension to attain the desired pressure lowering is difficult. Hence, in an attempt to avoid overly low IOP, most glaucoma surgeons suture the scleral flap tightly and perform 'laser suture lysis' as needed to break the sutures and allow the scleral flap to loosen. Unfortunately, completely severing sutures in this manner is frequently associated with a precipitous drop in IOP and hence this approach fails to adequately address the need for precisely-controlled IOP lowering. OBJECTIVES: In response to the need for precise incremental IOP lowering, we have designed a new ""laser-adjustable"" device for implantation during glaucoma surgery. The new device integrates a miniature mechanical structure capable of redistributing the mechanical tension of the suture when the device interacts with laser light. This leads to a conformational change, which decreases the tightness of the suture without completely severing it. This allows for incremental and controlled IOP lowering. The laser required to alter the device is a safe and has been used for decades in eye care and is widely available in all ophthalmology departments. Our proposed project builds upon our initial work and will involve prototype optimization and testing."