Drainage Device Targeting Canine and Feline Glaucoma
VetDC has an exclusive world-wide licensing agreement with Aqueous Biomedical Inc. to develop and commercialize Aqueous’s patented glaucoma drainage device in animals. This device is implanted in the outer layer of the eye to relieve over-pressurization caused by glaucoma.
LabradorGlaucoma is one of the leading causes of blindness in dogs, affecting more than 700,000 dogs in the US alone. In most cases of glaucoma, the eye’s drainage system becomes clogged so the fluid cannot drain. As the fluid builds up, it causes increased pressure inside the eye. Left untreated, high pressure damages the optic nerve and can result in gradual or sudden blindness.
Unfortunately, this debilitating disease is currently neither preventable nor curable. The only treatment is to lower the pressure. As a first line of defense, topical medication, eye drops and oral medicines, are usually prescribed to help either increase the exit of fluid from the eye or decrease the production of fluid in the eye. Pet owners can expect to administer one to four doses per day indefinitely to maintain proper pressure – which is an extremely inconvenient and expensive proposition for pet owners – and the drugs themselves have many side effects.
If drugs fail to control the pressure, surgical procedures are usually performed to cut through or remove tissue from the eye to allow increased outflow of aqueous humor. The common problem with all surgical procedures is the associated build-up of scar tissue, which decreases fluid outflow, necessitating repeated surgeries.
To overcome blockage caused by scar tissue formation, ophthalmologists may recommend a drainage (shunt) implant that has a tube connected to a plate. The tube end is inserted into the anterior chamber of the eye to keep the eye’s drainage channel open. The plate end of the shunt is inserted between the sclera and the conjunctiva to create a pocket that when pressurized with aqueous fluid forms a blister-like (spherical) cavity called a bleb. A fibrous capsule forms around the cavity, allowing aqueous humor to slowly vent through its walls and reduce the pressure inside the eye. It should be noted that current marketed shunt devices have not been optimized for use in animals.
Conventional wisdom among shunt developers is that the spherical blister is a necessary structure to prevent excessive outflow of fluid. However, the blister itself can cause significant complications. The four leading complications with the use of shunt devices are initial hypotony (pressure too low), diplopia (double vision), choroidal involvement (vascular supply to the retina becomes engorged with blood at the risk of bleeding and detachment) and fibrosis of the filtration capsule (the outer layer of the capsule becomes too thick to effectively vent fluid). Due to these complications, shunts are typically employed only as a last resort to save vision, and are rarely utilized in canine subjects. The VetDC glaucoma drainage device may potentially overcome such complications by radically changing implant geometry.
The VetDC patented technology utilizes split-tube geometry to make a more efficient cylindrical filtration capsule than the spherical blister capsules created by large tube-plate shunts.