To Fix a Lazy Eye, Total Darkness May Be Required
If you want to see the light, maybe you need to plunge into total darkness.
That appears to be the lesson of a study published in the journal Current Biology, which found that a certain type of vision loss in kittens could be reversed by leaving the kittens in a pitch black room for 10 days.
The study was conducted in kittens with amblyopia, a relatively rare condition that affects 4 percent of the world. The condition is marked by two eyes which do not see equally well at the beginning of life, when the connections from the eyes to the brain are still being developed. If the condition is not treated early, it can lead to complete and permanent vision loss.
The study was performed with the kittens by depriving them of any visual input to one eye. When those animals were set into the dark, their vision made a complete recovery. The researchers found that the treatment was successful because the loss of light caused the loss of neurofilaments that hold the entire visual system together. The treatment causes the visual system to revert to an earlier form of development. When these filaments are gone, the visual system is free to repair itself.
"There may be ways to increase brain plasticity and recover from disorders such as amblyopia without drug intervention," researcher Kevin Duffy, from Dalhousie University in Canada, said in a statement. "Immersion in total darkness seems to reset the visual brain to enable remarkable recovery."
The therapy may be suitable for treating amblyopia in human children, but researchers warn parents not to try it at home. To begin with, in order for the therapy to work, there needs to be utter, complete, absolute darkness, without any ray of light sneaking in. In addition, doctors would also need to find the original source of the condition, in order to make sure that the good eye is not damaged by plunging the child into absolute darkness.
The kittens were immersed in the dark for 10 days, but researchers still need to establish how long the therapy needs to last, and precisely how much darkness is needed. They doubt that any drug would be able to properly match their success.