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Homegrown device offers hope for complicated corneal procedure

A team of Australian researchers has received half a million dollars in medical research funding to fast-track development of a novel surgical device that addresses a common problem in delicate corneal transplant procedures.

Corneal researchers at the Centre for Eye Research Australia (CERA) and University of Melbourne colleagues have received funding from the Victorian Medical Research Acceleration Fund (VMRAF) to accelerate the development of CorGel, an ultra-thin hydrogel film that is used to insert donor corneal tissue into a patient’s eye to restore vision.

The $500,000 grant will support 18 months of preclinical work to refine and test CorGel – which dissolves safely into the body after surgery – in collaboration US eyebank EverSight.

CERA’s principal investigator Professor Mark Daniell said their goal after 18 months is to progress CorGel to a clinical trial and conduct the first human study.

The device, he said, was borne out of a challenge that had arisen in association with newer corneal transplant techniques, such as Descemet’s Membrane Endothelial Keratoplasty (DMEK) procedure, which replaces only the endothelium. DMEK procedures have better outcomes but make for difficult surgery.

“The reason we like transplanting just the endothelial layer is that it gives quicker recovery, the vision is better and we see less rejection,” Daniell said, adding that a 30% rejection rate has dropped to about 1% with DMEK.

“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 causing damage is technically difficult, which reduces the chance of successful surgery. As a result, many ophthalmologists choose other surgical procedures which aren’t as effective, Daniell said.

Revolutionising DMEK surgery 

The CorGel device works to address this; a key feature being that it keeps the donor corneal tissue flat when it is inserted into the eye.

Daniell said engineers have manufactured the CorGel film to be ultra-thin and transparent, but tough enough to withstand surgery.

“And when you put it in water it opens up nice and flat and so it is easy to position accurately.”

The 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,” Daniell said.

“At the moment, about one quarter of endothelial transplants in Australia and the United States are done by DMEK – but with CorGel all of these transplants could be done this way,” he said.

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,” Daniell said. “And this device aims to make the surgery so much easier that any corneal surgeon can do it.”

More reading 

Sydney ophthalmologist develops synthetic gel for corneal injuries

Operating the corneal eye bank

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