Called Leber’s hereditary optic neuropathy, this blindness is a disease of the mitochondria – the energy-generating power plants of our cells – inherited from the mother. It usually strikes men in their 20s, and total blindness sets in within 6 months of the first symptoms.
There had been no way to halt its rapid onset, but 6 months after taking a new drug called idebenone, some people whose sight had already begun deteriorating reported huge improvements in their vision.
The drug penetrates into the mitochondria, mopping up toxic free radicals to enhance mitochondrial function.
A team led by Patrick Chinnery of Newcastle University gave the new drug to 55 people (and placebos to 30).
- After 24 weeks, 11 people in the test group could read an extra two lines on a standard vision chart.
- And 9 people who couldn’t read any letters at the beginning of the trial could by the end.
- The drug was particularly beneficial for those who had better vision in one eye than the other, suggesting that it’s easier to treat the disease at its onset.
“We have seen patients who couldn't even see an eye chart on the wall go on to read the first line down – and some even attempted the second line,” Chinnery says. “For these patients, it can mean a vast improvement in their quality of life."
There were no serious side effects to the drug, and if carriers of the mutations can be identified through genetic testing, it might be possible to prevent their vision loss altogether by giving them the drug before symptoms develop.
Image by Jeff Dahl via Wikimedia