Cataracts are one of the most common forms of vision impairment, and unfortunately surgery is the only real treatment. But the clouds may be parting on a new drug treatment, improving the vision of the majority of mice it was tested on.
Cataracts occur as clumps of proteins that form on the lens of the eye, appearing as a cloudy area that can impair vision. They usually develop slowly with age, and if they get bad enough they can only be treated by surgically removing the lens and replacing it with a clear artificial one.
Drug treatments for cataracts have been tested in the past, with mixed results. A group of compounds known as oxysterols, including one called lanosterol, have managed to reduce the protein clumps in tests on dogs with cataracts. However, other studies have failed to reproduce the results.
For the new study, researchers used a different type of oxysterol, known as VP1-001. They applied the drug topically onto one eye of 26 mice with cataracts, while nine other mice were left untreated as controls.
The team found that 61 percent of the treated lenses showed an improvement to their refractive index profiles – a measure of their capacity to focus. The opacity of the lenses was reduced in 46 percent of the mice, as well.
“This study has shown the positive effects of a compound that had been proposed as an anti-cataract drug but never before tested on the optics of the lens,” said Professor Barbara Pierscionek, lead author of the study. “It is the first research of this kind in the world. It has shown that there is a remarkable difference and improvement in optics between eyes with the same type of cataract that were treated with the compound compared to those that were not.”
However the drug might not be a total panacea for cataracts. Some types didn’t respond as well as might be hoped, which might account for some of the failures in previous studies.
“Improvements occurred in some types of cataract but not in all indicating that this may be a treatment for specific cataracts,” said Pierscionek. “This suggests distinctions may need to be made between cataract types when developing anti-cataract medications. It is a significant step forward towards treating this extremely common condition with drugs rather than surgery.”
As always with animal studies, there’s still plenty of work to do, including checking whether the same mechanism works in humans.
The research was published in the journal Investigative Ophthalmology and Visual Science.
Source: Anglia Ruskin University