Retinal cures in sight

By Simon Jackson

Scientists at the University of Calgary published a new study last week which could shed new light into the causes of vision problems. The study in Human Molecular Genetics pinpoints the specific place in the retina where vision problems begin.

The U of C team, led by Dr. Torben Bech-Hansen stressed how excited they were with the findings, which could hold the key to a future cure for a wide range of visual impairments.

“We used genetics to investigate how the synapses in the eye help nerve cells to communicate,” said Bech-Hansen. “Damage to the retina looks the same under the microscope, whether it is the result of physical trauma–a detached retina–or a specific gene mutation.”

The team identified a calcium channel protein which passes signals through the eye. Using a mouse as a test subject they ‘turned on and off’ that calcium channel protein. They found the result mimicked the effects of night blindness in humans.

“The calcium channels are flags that we can follow, and are likely to lead us beyond the retina into other parts of the nervous system affected by human disease,” said Bech-Hansen. “We’re optimistic because there is a good chance to look at other aspects affecting vision, and perhaps even advance towards a cure.”

U of C graduate student Noelle Orton made many of the team’s observations.

“We make tiny slices of an eye where the calcium channel gene has been manipulated,” said Orton. “We then use an electroretinogram, or ERG, to test the synapses in the eye. Eyes in which the calcium channel is functioning properly show a strong ERG reading. Eyes in which the calcium channel is absent do not.”

The small team are building on initial observations made in 1998 when they discovered the gene. The current project is collaborative and includes researchers in both the U of C and Halifax. The team is focusing their study on a disease known as congenital stationary night blindness, which affects one in every 10,000 people.

Bech-Hansen stressed that although it is too early to say exactly what will come of the findings, it is possible that scientists could recreate the calcium channel for all patients in whom it is damaged or missing and the potential exists to cure a number of eye ailments.

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