Scientists have successfully restored the vision of 12 infants born with congenital cataracts in the trial of a treatment which regenerates the eye’s lens.
The children’s sight was restored in a procedure which removes the cataracts from a patient and allows stem cells to regenerate a clear, working lens.
Mark Daniell, an associate professor of ophthalmology at the Centre for Eye Research Australia, said cataract surgery was one of the most common forms of surgery done in the western world and its treatment had been almost the same for a number of years.
“So to have a paradigm shift like this is quite extraordinary,” he said.
“The current technique for removing cataract involves removing the surface membrane of the lens and then the entire opaque central part of the lens.
“What they’ve done in this study is they’ve managed to leave the layer of cells that can regenerate a lens intact and just remove the cloudy central lens material.
“So remove the cataract, but leave the membrane around the cataract intact with all of the cells in them and those cells almost miraculously managed to recreate a lens over six or nine months.”
The treatment has been developed by researchers at Sun Yat-sen University and the University of California, San Diego.
Dr Kang Zhang, the chief of Ophthalmic Genetics at the Institute for Genomic Medicine at the University of California in San Diego, and lead author of the study, said he hopes a similar procedure could help older patients with cataracts.
“I think the same principle applies to another condition called age-related cataract, which is the most common cause of blindness worldwide,” Dr Zhang said.
“So what we are actually planning to do is to expand this study into adult cataracts.”
The first infant to be treated in the trial had the procedure two years ago and the children involved still have normal vision.
The researchers also reported fewer complications and speedier healing for patients in the trial, compared to current treatments.
Scientists optimistic they can soon treat adults
Associate Professor Daniell said treating children with cataracts is more complicated than treating adults, but said he was optimistic about this research.
“Adult cataract surgery, we put an artificial lens in to replace the refractive power of the lens so that people don’t need to wear glasses,” Associate Professor Daniell said.
“With a child, operating on a very small child or a baby, their eyes continue to grow so you can’t use the usual intraocular lenses.
“Some people worry that intraocular lenses can damage the inside of the eye, causing inflammation so children without intraocular lenses, they’ve had to have contact lenses fitted and you can imagine fitting contact lens on a baby is extremely difficult.
“If you don’t replace the refractive power of the lens in some way, the baby develops dense amblyopia, dense lazy eye and won’t be able to see out of the eye so surgery is not useful.
“So they’ve been a very complicated group to operate on and the results hasn’t been as good as they could possibly be.
“This way … if the lens regenerate naturally and regains not only sight but … the ability to change its focus, that would be a miraculous improvement.”
In a separate study also published in Nature, researchers reported being able to regenerate different types of tissue from the eye using stem cells.
Stephanie Watson, a clinical professor at the Save Sight Institute, said stem cells grow different types of ocular tissues and most techniques to date have focused on growing one particular eye tissue or cell at a time.
“Where often in eye diseases, more than one layer might be affected by injury or disease and so it was a way of basically moving towards recreating an eye,” she said.