White Light–Emitting Diodes (LEDs) at Domestic Lighting Levels and Retinal Injury in a Rat Model

Abstract

Background: Light-emitting diodes (LEDs) deliver higher levels of blue light to the retina than do conventional domestic light sources. Chronic exposure to high-intensity light (2,000–10,000 lux) has previously been found to result in light-induced retinal injury, but chronic exposure to relatively low-intensity (750 lux) light has not been previously assessed with LEDs in a rodent model.Objective: We examined LED-induced retinal neuronal cell damage in the Sprague-Dawley rat using functional, histological, and biochemical measurements.Methods: We used blue LEDs (460 nm) and full-spectrum white LEDs, coupled with matching compact fluorescent lights, for exposures. Pathological examinations included electroretinogram, hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC), and transmission electron microscopy (TEM). We also measured free radical production in the retina to determine the oxidative stress level.Results: H&E staining and TEM revealed apoptosis and necrosis of photoreceptors, which indicated blue-light induced photochemical injury of the retina. Free radical production in the retina was increased in LED-exposed groups. IHC staining demonstrated that oxidative stress was associated with retinal injury. Although we found serious retinal light injury in LED groups, the compact fluorescent lamp (CFL) groups showed moderate to mild injury.Conclusion: Our results raise questions about adverse effects on the retina from chronic exposure to LED light compared with other light sources that have less blue light. Thus, we suggest a precautionary approach with regard to the use of blue-rich “white” LEDs for general lighting.Citation: Shang YM, Wang GS, Sliney D, Yang CH, Lee LL. 2014. White light–emitting diodes (LEDs) at domestic lighting levels and retinal injury in a rat model. Environ Health Perspect 122:269–276; http://dx.doi.org/10.1289/ehp.1307294

Retinal damage induced by commercial light emitting diodes (LEDs)

“…Using a comparable set of experiments Shang's team recently show that white LEDs lead to photoreceptors death [58], with an important oxidative stress, as we confirmed in this paper, however, according to our data, apoptosis is not the major pathway involved in photoreceptor demise. Actually, the experimental design of Shang's et al has several differences with ours but two differences are very important: first they use dark adapted animals, a procedure that increases retinal sensitivity to light.…”

The Involvement of the Oxidative Stress in Murine Blue LED Light-Induced Retinal Damage Model

“…They showed that decrease of visual function, accompanied with ONL atrophy, and increased markers of oxidative stress in response to blue LED light exposure for day 9. 21) In mice, blue LED light exposure (1000 lx, 12 h/d, 1 week) induced phospholipid oxidation and upregulated monocyte chemoattactant protein-1, whereas blue LED light exposure (500 lx, 12 h every 2 d, for 4 or 6 month) induced angiogenesis in another study. 22) These models are not adequate to assess drug efficacy as the timelines are long, whereas the model presented in this study, which demonstrated retinal injury 5 d after exposure may be appropriate for investigating the mechanism of retinal damage as well as the potential interventions to reverse or alleviate damage induced by blue LED light.…”

“…Previous blue LED-induced retinal damage model caused the damage by directly exposure of blue LED to eye under ketamine-xylazine anesthesia or exposure in cage that mice were moving freely. [19][20][21][22] Previous report showed that the light-induced retinal damage was decreased under ketamine-xylazine anesthesia. 23) We used the mirrored device separated individually by clear board for the reflection of blue LED light in non-anesthesia.…”

“…Therefore, we succeeded the induction of the retinal damage by 12 times lower intensity and 6 times shorter hours of blue LED exposure than the previous model. 19,21,22) While several studies reported that NAC protected against light-induced retinal damage, 13,14) no studies exist that that showed its protective effect in an in vivo model of LED light-induced retinal damage. In the present study, NAC was protective against murine blue LED light-induced retinal damage.…”

Smart-Glasses: Exposing and Elucidating the Ethical Issues

“…Although there is no evidence this is the case for humans, animal experiments with LED light discovered greatly hastened macular degeneration (Sliney 1984;Shang et al 2014). Additionally, blue-rich displays are also known to influence the circadian rhythms of their users by suppressing the hormone melatonin levels which aids sleep (Cajochen et al 2011).…”