Light-emitting-diode induced retinal damage and its wavelength dependency in vivo

AIM: To examine light-emitting-diode(LED)-induced retinal neuronal cell damage and its wavelength-driven pathogenic mechanisms.METHODS: Sprague-Dawley rats were exposed to blue LEDs(460 nm),green LEDs(530 nm),and red LEDs(620 nm).Electroretinography(ERG),Hematoxylin and eosin(H&E) staining,transmission electron microscopy(TEM),terminal deoxynucleotidyl transferase d UTP nick end labeling(TUNEL),and immunohistochemical(IHC) staining,Western blotting(WB) and the detection of superoxide anion(O-2·),hydrogen peroxide(H2O2),total iron,and ferric(Fe3+) levels were applied.RESULTS: ERG results showed the blue LED group induced more functional damage than that of green or red LED groups.H&E staining,TUNEL,IHC,and TEM revealed apoptosis and necrosis of photoreceptors and RPE,which indicated blue LED also induced more photochemical injury.Free radical production and iron-related molecular marker expressions demonstrated that oxidative stress and ironoverload were associated with retinal injury.WB assays correspondingly showed that defense gene expression was up-regulated after the LED light exposure with a wavelength dependency.CONCLUSION: The study results indicate that LED bluelight exposure poses a great risk of retinal injury in awake,task-oriented rod-dominant animals.The wavelengthdependent effect should be considered carefully when switching to LED lighting applications.