The use of computers and electronic devices plays a predominant role in the daily activities of modern society. Most of these tools make use of liquid crystal display (Liquid Crystal Display, LCD) who are backlit by light-emitting diode or LED (Light Emitting Diode). LEDs, compared to conventional light sources (fluorescent lamp), emit higher levels of blue light at shorter wavelengths who have an increased risk of photo-injury. Several studies have shown that extensive exposure to blue light influences the circadian rhythms interrupting them and thus constituting a risk to human health; for example, night lighting with blue light and the desynchronisation of circadian rhythms can increase the incidence of psychiatric disorders, diabetes, obesity and several types of cancer.
LCD screens and retina damage
I retinal photoreceptors and retinal pigment epithelium cells (EPR) represent the parts of the eye that absorb the most  light energy and it has been shown that shorter wavelength lights induce more retinal damage than those with longer wavelengths. In particular, some authors have observed, in animal models, LED-induced damage in EPR cells and retinal photoreceptorseven at home lighting levels. Epidemiological and experimental evidence has, moreover, revealed that exposure to short wavelength light may contribute to the pathogenesis of age-related macular degeneration (DMS). In particular, studies have revealed that Retinal damage is linked to the formation of reactive oxygen species (ROS) and inflammatory reactions that induce oxidative stress and cell apoptosis in the retina.
Retinal injury induced by exposure to short wavelength light is the subject of many studies, also in connection with the increasing exposure to displays emitting high levels of blue light. However, although progress has been made in relation to possible treatments, their effectiveness remains limited to date. In order to prevent blue light-induced damage to the retina and disruption of circadian rhythms, the following have been widely used filters, blocking lenses and intraocular lenses with blue light filter. However, these systems can reduce light brightness, but also contrast sensitivity and vision quality.
A recent paper published in International Journal of Molecular Science further investigated the effects of the light spectrum emitted by LCDs on LED-induced damage to retinal photoreceptor cells. The authors also designed an alternative LCD with a reduced energy output but the same brightness. The study also established a ocular energy exposure index-OEEI) which could be used as an indicator of LCD energy output.
In the publication, the authors demonstrated that exposure to LCD caused damage to retinal photoreceptor cells proportional to the level of emitted energy. LCDs that emitted energy with a high OEEI led to a greater decrease in cell viability and an increase in apoptosis (cell death). This was because exposure to high-energy light induced ROS production and destroyed mitochondrial function. LCDs with lower energy output could therefore be used to build screens to prevent light-induced retinal damage and protect the health of our eyes.
Source:
Effects of the Emitted Light Spectrum of Liquid Crystal Displays on Light-Induced Retinal Photoreceptor Cell Damage. Chao-Wen Lin, Chung-May Yang and Chang-Hao Yang. Int. J. Mol. Sci. 201
Dr. Carmelo Chines
Direttore responsabile