An Engineered Virus Could Cure Color Blindness

Many people are looking for a correction of their color blindness. Gene therapy for color blindness passes first phase of human testing.

Can Lasik Fix Color Blindness?

Laser eye surgery is able to make physical changes to the cornea, a part of the eye that is not related to color vision deficiencies. While there are no surgical interventions or other cures known at this point for color blindness.

Can Red-green Colorblindness Be Corrected?

The most common form of color blindness is red-green color blindness. People with this condition have a hard time distinguishing between different shades of reds and greens. There's no cure for color blindness yet, and no medical treatments currently exist for inherited forms of color blindness.

SCIENTISTS ARE TESTING GENE THERAPY IN PEOPLE WHO SEE IN MONOCHROME (black, white, and shades of gray).

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In a small trial in Germany, an experimental gene therapy improved the vision of nine people with total color blindness, also known as known as achromatopsia. After receiving the gene therapy, the eight men and one woman in the trial could see some color, as well as more letters on a vision chart.

Developed by researchers at the Ludwig Maximilian University of Munich and University Hospital Tübingen, the therapy, which involves a genetically engineered virus, is designed to correct a defect in a gene known as CNGA3. Mutations in this gene are responsible for about one-third of all cases of total color blindness.

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Gene therapy uses viruses because of their natural ability to get inside cells. The viruses are modified, however, so that they can’t cause infection, and they’re also engineered to carry healthy copies of a gene to compensate for a mutated one. In this case, the scientists in Germany inserted normal copies of the CNGA3 gene into the engineered virus particles. The hope was that the healthy version of the gene would correct the eye’s cone cells, which are faulty in people who are color blind.

Each of the participants received an injection of the drug in one eye (their worse one) then waited a few weeks for it to take effect. Though the study was mainly intended to test the safety of the approach, the researchers found that the therapy improved vision somewhat in terms of focus, contrast, and color vision. The results were published on April 30 in the journalJAMA Ophthalmology.

For years, scientists have imagined gene therapy as a way to correct red-green color blindness, the most common type of color vision deficiency.

In 2009, researchers had a breakthrough when they cured red-green color blindness in adult monkeys using gene therapy, but there have not been clinical trials yet for gene therapy that aims to correct this type of color blindness on humans. Instead, researchers have focused their efforts on trying to cure the more severe achromatopsia. These trials, which use a similar approach as the one in Germany, are ongoing in the United States and in the U.K. If the approach works, it could open the door to correcting more common forms of color blindness, which are typically inherited.

The German researchers think the therapy will be more effective if patients receive it in childhood, when the brain is still able to rewire itself.

This of course is an early trial, and the therapy will need to be tested in more patients before it can be approved. If that happens, it could still be out of reach for many people. A gene therapy designed to restore vision is already on the market, but in the United States it costs $850,000 — or $425,000 per eye.

Called Luxturna, it was approved by the Food and Drug Administration in December 2017 for children and adults with a rare genetic mutation that often results in blindness.

THE HOPE IS THAT THEIR EFFECTS WILL LAST A LIFETIME.