Researchers at Dalhousie Medical School have discovered a drug to stop babies born with familial exudative vitreoretinopathy (FEVR) from going blind. FEVR is a hereditary disorder that prevents blood vessels from forming around the retina, reducing blood supply and causing progressive vision loss.

Professor Chris McMaster, head of the department of pharmacology, is optimistic as initial test on the animal models are successful. Going forward, they must now calculate the dosage and safety protocols of the drugs before clinical trials in children.

However, his breakthrough would not have been possible were it not for the ophthalmologist Dr. Johane Robitaille and her team’s 2002 seminal discovery of the FEVR gene mutations and its mechanism. Through mutating the FEVR gene, she found the veins and arteries in the retina were not developing properly. The landmark identification of FEVR allowed McMaster to build on her work to find a way to repair this mutation.

Working against FEVR’s pathology

Robitaille was enthusiastic about the new drug’s potential, saying that “This drug would enable the vessels in the retina to grow (in the newborns) and complete their development. We can facilitate that with this therapy, so that we can prevent the FEVR-related complications from happening. It would work directly against the pathology that causes the blindness.”

What makes McMaster's breakthrough significant is that while complications from FEVR can be managed, no treatment has been available. However, the drug has its limitations.

McMaster and Robitaille plans to start clinical trials for the drug within four years, but only in newborns screened positive for FEVR's genetic mutation, before any scar tissues surface. This is because the drug does not treat scar tissues, but prevents it from occurring. In FEVR, it is the scaring around the retina that causes the blindness.

Precision eye surgery performed successfully

But all hope is not lost for FEVR-affected newborns who have developed scar tissues. In September, doctors at John Radcliffe hospital in England successfully removed a membrane 1/100 of a millimetre thick from a patient's retina without damaging any part of the eye, using a robot.

Previously, this procedure was fraught with difficulties due to the high level of precision involved. With the robot, a 3D precision that is necessary to operate inside the human eye is achieved, and as a result, enables many previously infeasible eye surgeries to treat the eye and blindness.

“There is no doubt in my mind that we have just witnessed a vision of eye surgery in the future,” Professor Robert MacLaren, the lead surgeon said.

“Current technology with laser scanners and microscopes allows us to monitor retinal diseases at the microscopic level, but the things we see are beyond the physiological limit of what the human hand can operate on. With a robotic system, we open up a whole new chapter of eye operations that currently cannot be performed.”

“This will help to develop novel surgical treatments for blindness, such as gene therapy and stem cells, which need to be inserted under the retina with a high degree of precision,” he added.

FEVR drug may cure ROP as well

Upon passing clinical trials stages and into implementation, McMaster's team is hopeful that the same drug can be used to cure babies of the number one cause of blindness in developed nations: retinopathy of prematurity (ROP).

The pathology of ROP is similar to FEVR and if the drug works for FEVR, it may cure ROP too, Dr. Robitaille added optimistically.

In Singapore, approximately 30% of all premature babies develop ROP. In most cases ROS would recover without additional medical assistance, but 6% would require laser treatment. Close monitoring of ROP is necessary – conducted by Singapore National Eye Centre paediatric ophthalmologists – as up to 18% of the cases would progress into Stage 4 – 5, which requires swift and more complex treatment. MIMS

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