EyeWorld India June 2019 Issue

70 EWAP JUNE 2019 NEWS & OPINION Reactive oxygen concerns “We started investigating and found that the retinal absorbs blue light,” Dr. Karunarathne said. “Then, this molecule goes to a high-energy state and the high-energy state can deliver that high energy into oxygen.” The eye itself is well oxygenated, and the transfer of the energy makes the oxygen toxic and becomes what is known as a reactive oxygen species, Dr. Karunarathne said. Hydrogen peroxide is one of the reactive oxygen species, and when you place a drop on the skin, you can see bubbles as it reacts. As part of their work, investigators found that when they exposed cultured cells to blue light the retinal molecule ended up attacking important biomolecules needed for cell survival, likely by generating reactive oxygen species. “If you expose them to retinal and blue light long enough, cells die,” Dr. Karunarathne said. Investigators also discovered that alpha tocopherol, a molecule derived from vitamin E, can prevent this cell death. “We found that alpha tocopherol can quench and neutralize these toxic reactions and prevent the damage to cells,” Dr. Karunarathne said. While it is unknown whether blue light from devices such as smartphones and computers is intense enough to induce this type of toxic reaction in the iÞi] ܓi ÃVˆi˜ÌˆwV ˆÌiÀ>ÌÕÀi suggests that blue light induces vision damage. “We wonder if the previously reported blue light-induced vision damage is from the same set of reactions that we observed,” Dr. Karunarathne wondered. “We don’t know yet and we are looking into that.” Role for vitamin E In addition, they are also investigating the potential role of vitamin E. “We think this ëiVˆwV “œiVՏi vÀœ“ ۈÌ>“ˆ˜ E is a natural antioxidant and alpha tocopherol is, too,” Dr. Karunarathne said. “We think this is going into the same location in the cell where retinal accumulates, so this can directly take up those reactive species and neutralize them.” Practically speaking, while Dr. Karunarathne understands concerns that the public has about blue light emanating from current technology, he stressed that it remains unknown what effect these truly have. Although retinal is known to be in the eye, it is unknown how much free retinal is available to induce this toxic reaction. “I think the human body is very resilient; we have natural antioxidant machinery,” Dr. Karunarathne said. However, in cases where people have problems with the retinal clearance mechanism, they may be more vulnerable to damage by blue light. “In general, I’m not too worried that the light from mobile devices can induce substantial vision damage,” he said. “I use my mobile phone and computer every day and I’m not wearing any glasses at this point because I want to see what the upcoming experiments tell us.” EWAP Reference 1. Ratnayake K, et al. Blue light excited retinal intercepts cellular signaling. -Vˆ ,i« . 2018;8:10207. Kasun Ratnayake (left), Dr. Karunarathne (middle), and Dr. John Payton (right) work on a blue light exposure experiment. Source (all): Ajith Karunarathne, PhD