Lighting specialists are questioning the validity of a report by researchers at the University of Madrid which claims that the blue light from LEDs causes damage to human retina cells.
In the study, researchers at Complutence University exposed In Vitro retinal pigment epithelium cells from healthy human donors to light from blue, green, red and white LEDs during a 12-hour-light/12-hour-dark cycle and then observed the samples for light-induced cell death.
In their conclusion to the experiment the researchers said exposure to LED light during such a light/dark cycle, especially in the shorter wavelengths of blue light, harms retinal pigment epithelium cells in comparison to a non-exposed control group. They went on to suggest future studies are now needed to ascertain which intensities, wavelengths and exposure times of LED lighting devices are lethal and non-lethal for retinal tissue.
The report has subsequently been referenced by the Daily Mail, which asked in a headline, ‘Do environmentally-friendly LED lights cause BLINDNESS?’ One of its authors has also been quoted as saying that the implications of the report could be worse because of the widespread use of LEDs in lighting, computers, mobile phones and television screens. “This problem is going to get worse, because humans are living longer and children are using electronic devices from a young age, particularly for schoolwork, instead of paper,” Dr. Cecilia Sanchez Ramos told Thinkspain.com
However, elements of the lighting industry have questioned the study because they think it fails to simulate realistic conditions for the retinal cells. Steve Poole, technical/quality director at Projection Lighting, and a former manager at the Lighting Association Laboratories, where safety assessments of LEDs were performed in accordance with EN62471, has seen a copy of the report, and said: “It think this is interesting but flawed. The report describes the exposure levels that the retinal cells were subjected to, but they aren’t really relevant,” he said. “The conditions in the study are the equivalent of staring at blue light equivalent to a 100W incandescent source at 20cm distance for 12 hours, which isn’t a realistic level of exposure for me,” he said.
Fenella Frost, of PhotonStar, argued that the more research was needed into how the eye mitigates blue light hazard through pupil dilation: “iPRGCs [The eye’s photosensitive ganglion cell, or ‘third receptor’], discovered by Foster, reacts specifically to blue light and controls the pupillary reflex. The understanding of these cells is ongoing and perhaps this should be considered given their specific reaction to blue light,” she said.
