Light emitted from digital screens can cause irreversible damage to eyes, research shows

Jan 27 2017

The University Complutense of Madrid (UCM), one of the oldest Universities in the world, presents the results of its latest research confirming the irreversible damage to animals’ eyes caused by light emitted from digital screens. This groundbreaking report analyzes and compares the results of a study exposing the retina of rats to tablet screens emitting white LED light with and without filters, proving that light causes cell death in the retina, and can lead to loss of vision.

The quantitative analysis shows that after three months of exposure (life expectancy of these rats is between 7-10 years) to white LED light, animals exposed to tablets experienced approximately a 23 percent increase in retina cell death. Additionally, when the appropriate physical filter was placed on the screens of the tablet that absorbed the harmful high energy light, there was no retina cell death.

“These results are important because LED screens are being used by the majority of the population, adults and children, for work, school and entertainment. This study indicates a possible massive risk for the human population, taking into consideration that retina damage is the biggest cause of central blindness,” said Dr. Celia Sanchez-Ramos, lead researcher. “It is paramount for adults and parents to act now and protect themselves from further damage. We have studied the risks of high-energy light for the last 15 years, and it is now clearer than ever that we are facing a new global epidemic, especially for younger generations who experience screen exposure from an early age.”

Structural and gene expression damages were studied on the retina of pigmented rats, which were divided into three groups [exposed group, protected group and controlled group]. The first group was exposed to white LED light from tablet screens that are currently in the market. The second group was made up of rats of the same race exposed to white LED light from tablet screens with an external filter called Reticare, the only eye protector based on scientific data. The physical filter (Reticare) was placed on the screen of the tablet to absorb the correct amount of short wavelength light.

The methodology used for light exposure consisted of six tablets placed only around the sides of the cages (not at the top or the bottom of the cages). The tablets were switched on for 16 hours and then switched off for eight hours a day over a three-month period. In both cases, with and without filters, the results were compared with animals in the controlled group.

When looking at the retinal structural analysis in each group, it showed a significant reduction of 23 percent in the number of nuclear cell layers in rats that were exposed to unfiltered light from tablets. Rats exposed to filtered with Reticare eye protection white LED light did not show significant differences in retina layers.

Furthermore, the results of the study showed a decrease in the expression of genes involved in the prevention of apoptosis (antiapoptotic) cell death and an overexpression of some of the genes that favor cell death (proapoptotic) in rats exposed to tablets without filter. The retinas of the rats in the second group that were exposed to filtered screens showed a protective effect on the cells of the retina of the animals. Also, the study demonstrates that exposure to LED light from the tablet screens favors the expression of genes that promote cell death and the enzymes involved in causing cell death. These effects are largely reversed by using the appropriate filter on tablet screens.

After disclosing these results, it concludes the importance of preventative measures that appropriate eye protectors already in the market can offer, such as Reticare’s products which are based on UCM’s studies. Reticare, for the past three years, has been an advocate for raising awareness of the need to use scientifically validated protection against the serious risks involving the use of digital screens without proper eye protection.

Study II - Calculation of ocular lighting

A second study, “Calculation of ocular lighting,” quantified the amount of light entering the eye based on the device, the user, the diameter of the pupil and the distance of the device to the eye. To accomplish this, scientists measured the emission of the LED screens from different devices and calculated the amount of high energy light.

LED displays of digital devices (smartphones, tablets, computers and game consoles) emit light with high proportion of short wavelength, which is a visible radiation that is characterized by being highly energetic and can cause damage to the eyes. The effects this radiation could have on the eyes depends on the spectral composition of the light, the time of use and the distance from the eyes. Thus, the amount of light emitted by the screens that reaches the eyes of the user is directly proportional to the pupillary diameter, and it is inversely related to the square of the distance of the device to the eye. It is important to differentiate a blurry vision (optical refraction) with the retinal damage that can lead to central blindness and eventually impede vision during certain activities (i.e., driving, reading, cooking, etc.).

In a first evaluation of the amount of light that reaches the eyes, the diameter of the pupil and the distance to which the adults use the different devices were taken into consideration. Devices used: Smartphones: 9.85”- 13.79”, Tablets: 11.82”- 15.76”, Computers: 17.73”- 19.7”

The results emphasize children receive three times more light of short wavelength. Due to their shorter arms, they are exposed to high energy light at a shorter distance than an adult who uses the same device. Therefore, it is crucial for public health officials to focus on the consequences of extreme exposure to this light, which children and adults experience on a daily basis.

We currently spend many hours exposed to light emitted by LED screens with high content of shortwave light. Numerous studies have already shown that high-frequency radiation is capable of producing damage to retinal cells (such as macular degeneration and retinopathy) and can lead to central blindness (Chamorro et al., 2013; Sparrow 2003; Behar-Cohen et al., 2011, Jaadane et al., 2015, Shang et al., 2014).

Similarly, historically, research of more than 2,000 children, aged eight to 18 years, reported that, on an average day, they spend approximately 7.5 hours using devices with LED displays in academic and leisure activities. The approximate distribution of this time is 4.5 hours watching television, 1.5 hours on computer tasks and more than an hour with video games (Rosenfield 2011).

Currently, there are approximately 900 million devices. Of those, 70 million are used by children in the U.S. without eye protection. To date, more than 300,000 people already protect their eyes in Europe and in the United States with the appropriate filters based on this data.

Recently, the European Government established a scientific commission prioritizing the study of screen risks to eye health, and has demanded all researchers to provide the results of their work including the potential consequences of visual health of populations concerning this topic.