Heat advisory in effect from noon until 7 p.m.

YOUR HEALTH Gene therapy for better eyesight

GAINESVILLE, Florida – Imagine only being able to see the things in front of you in soft focus, and just in black and white.

For people with the genetic eye condition achromatopsia, those are just some of the side effects.

Each time Tara Cataldo prepares to leave her house, she has to make sure her face is completely shielded from the sun.

"I need to have very dark, very tinted sunglasses to feel comfortable outside, to see really well," said Tara.

Tara has achromatopsia, a genetic condition that makes her eyes incredibly sensitive to light.
She is also very nearsighted; even while wearing glasses or contacts, she can only see clearly at a very short distance.

"I cannot drive a car so I rely on public transportation and my bike to get around," she said.

  • Achromatopsia is a hereditary and non-progressive visual disorder that is characterized by decreased vision, light sensitivity, and the absence of color in a patient`s vision
  • It's sometimes called "day blindness" because patients can see better in dimmer light
  • Complete achromatopsia will have reduced vision of 20/200 or less due to an abnormality of the retina
  • Patients may also have the presence of nystagmus or shaking of the eyes.

"There are currently no approved or no effective treatments for achromatopsia," said Dr. Christine Kay, a surgical ophthalmologist at the University of Florida.

But she's working to change that.

She is one of a handful of experts testing a gene therapy.

"For achromatopsia the cells we have to target are cone cells responsible for decreased vision and color vision. and those are cells at the very bottom layer of the retina," explained Dr. Kay.

Using a tiny cannula, doctors deliver a normal copy of one of two mutated genes, the CNGA-3 or CNGB-3 gene, directly into the eye to restore vision.

Tara`s myopia is so severe that her risk of retinal detachment from any retinal surgery is high, which rules her out for the current trial.

In the meantime, Tara says she's learned to adapt to achromatopsia and live without limitations.

"And I hope, ya know, all young achromats, ya know, learn the same thing."

Dr Kay says if the gene could eventually be delivered to the surface of the retina, additional patients, like Tara, could be treated.   AGTC, the biotech company that developed the therapies, and several U.S. universities have successfully tested this therapy in dogs and sheep.

NEW TECHNOLOGY: A new clinical trial is underway testing gene therapy for achromatopsia. The genes are responsible for releasing proteins essential for the function of all the cells. Researchers remove the virus from the host DNA so it does not have the capacity to make the patient sick, and then insert the gene of interest into the DNA. Surgically done by a vitro retinal surgeon, the gene is then directly delivered to the retinal tissue. Researchers try to avoid directly touching the retina, to avoid detaching it and keep the surgery less evasive. The CNGA3 or CNGB3 gene would help restore the patient`s vision. This can only be done on certain patients; those with extremely severe achromatopsia are not able to participate in this trial because of the risk of retinal rupturing.

If this story has impacted your life or prompted you or someone you know to seek or change treatments, please let us know by contacting Jim Mertens at jim.mertens@wqad.com or Marjorie Bekaert Thomas at mthomas@ivanhoe.com.