Professor Mark Daniell.
Critical research to improve corneal transplants for millions of patients worldwide is on the fast-track to clinical trial thanks to major funding from the Victorian Medical Research Acceleration Fund (VMRAF).
The Centre for Eye Research Australia’s corneal researchers and University of Melbourne colleagues have received the funding to accelerate the development of a surgical device known as ‘CorGel’, an ultra thin hydrogel film that is used to insert donor corneal tissue into a patient’s eye to restore vision. After surgery the gel dissolves safely into the body.
The $500,000 grant from VRMAF will make a major contribution to 18 months of preclinical work to refine and test CorGel in collaboration with the University and US eyebank EverSight.
“Our goal at the end of this 18 months is to get CorGel into a clinical trial and do the first human study,” says Professor Mark Daniell, CERA’s Principal Investigator Corneal Research.
Corneal disease is a leading cause of blindness
The cornea is the clear, front window into the eye. Damage to the cornea from injury and diseases such as Fuch’s Dystrophy is a leading cause of blindness globally, along with cataract, macular degeneration and glaucoma.
While damaged corneal cells cannot repair themselves in the human body, healthy donor corneal tissue can be successfully transplanted to restore sight. Corneal transplants are now the most common form of transplantation undertaken in hospitals today.
“About 12 million people in the world are blind from corneal disease,” says Professor Daniell. “And there’s probably four or five million people waiting for corneal transplants.”
There are different types of corneal transplant surgeries depending on where the damage is located. Historically, the surgery has involved cutting through all layers of the cornea to remove the affected part.
But where damage is limited to the innermost layer of the eye, a newer technique replaces only this layer, the endothelium. The procedure is called Descemet’s Membrane Endothelial Keratoplasty, or DMEK.
“The reason we like transplanting just the endothelial layer is that it gives quicker recovery, the vision is better and we see less rejection,” says Professor Daniell. “What was a 30 per cent rejection rate is now about 1 per cent with the DMEK operation.”
But it can be very difficult surgery, he says.
“Rather than transplant the whole cornea, we’ve taken just a single layer of cells from the donor, with some of the Descemet’s membrane on the back. And this graft membrane tends to scroll up when we insert it into the eye.”
Unscrolling the delicate graft membrane without damaging it is technically difficult, which reduces the chance of successful surgery. As a result, many ophthalmologists around the world have chosen other surgical procedures which aren’t as effective, says Professor Daniell.
The CorGel ‘scaffold’ keeps tissue flat
The CorGel device invented by the CERA team has the potential to be a game changer. Its key feature is that it keeps the donor corneal tissue flat when it is inserted into the eye.
“What our engineers have done is manufacture the CorGel film so it is ultra thin and transparent but tough enough to withstand surgery,” says Professor Daniell. “And when you put it in water it opens up nice and flat and so it is easy to position accurately.”
Donor corneal endothelium is stuck to the CorGel film ‘scaffold’, using a light activated bio-glue, and inserted into the back of the eye. The film is made from the same material as capsules – ‘PEG’ or polyethylene glycol – and dissolves into non-toxic by-products within a few weeks. “By that stage the cells will have attached and started to work as a corneal transplant,” says Professor Daniell.
“At the moment, about one quarter of endothelial transplants in Australia and the United States are done by DMEK,” he says. “But with CorGel all of these transplants could be done this way.”
The CorGel device has the potential to make DMEK surgery the default endothelial corneal transplant method around the world through being quicker, safer and more efficient. “It is technically the best surgery,” he says. “And this device aims to make the surgery so much easier that any corneal surgeon can do it.”