`Light therapy` can save vision in preemies
Melbourne: Scientists have found that an inexpensive light therapy can prevent a disease that strikes children born prematurely, causing loss of vision.
Researchers at Australia's Vision Centre found that retinopathy of prematurity, a leading cause of infant blindness in developed countries, can be treated with near-infrared (NIR) light therapy.
"As our sight develops, blood vessels grow at the back of our eyes to provide nutrients and oxygen to the retinas," said Dr Krisztina Valter of The Vision Centre and The Australian National University.
"However, in premature babies, these retinal vessels are not fully developed, and when these babies are placed under oxygen therapy to support their immature lungs, the high levels of oxygen can release free radicals in the retina, causing damage in the tissue.
"Most importantly, the cells that are important for the proper growth of blood vessels are the targets of the damaging free radicals.
"That means that once the babies can be returned to normal air when their lungs are fully developed, they now have blood vessels growing uncontrollably in all directions in the eyes.
"These vessels bleed easily, which can result in severe changes and damage of the retina, causing irreversible loss of vision," Valter said.
The current treatment for the disease is surgery or using a laser to seal off the bad vessels, Dr Riccardo Natoli of The VC and Australian National University (ANU) said.
"However, these treatments are expensive, invasive and often have side effects, including destroying portions of the child's peripheral vision," he said.
Now, using animal models that mimic the disease, Vision Centre researchers have found that shining gentle near-infrared light (NIR) at 670 nanometres (nm) is a potential treatment that is less invasive, inexpensive and free of side effects.
"We found that NIR treatment can greatly decrease the risk of developing retinopathy of prematurity. There were fewer vessels growing in the wrong directions, and also a significant decrease of bleeding from the newly grown vessels," Natoli said.
"While there were still some vessels that grew out of bounds in the experimental animals, they were far fewer than in animals that did not receive NIR treatment.
"We don't fully understand the process of how the NIR light protects the eyes, but we suggest that the light sends a signal to the mitochondria - the 'powerhouse' of every animal cell - to use oxygen more efficiently, resulting in fewer free radicals and less damage," he said.
The researchers said this is the first study to show that NIR therapy can protect the retina from exposure to high levels of oxygen, and are currently running human trials to test NIR light in premature babies.