What do your cell phone, computer, and television all have in common? They all are made of light emitting diodes (LEDs). LEDs are very useful as they are small in size allowing them to fit into these devices, along with having a long lifespan making them the light of choice for most technology. However, LEDs emit different wavelengths of light, with the most prominent and the most harmful being blue light. While LEDs are useful, most people do not know the risk they pose to eye health.
Our eyes are very susceptible to blue light, as our corneas do not block blue light in the same way that they block ultraviolet light. So, blue light reaches all the way to the back of our eyes, and penetrates our retinas and retinal cells. In fact, recent research has determined that progressive exposure to blue light not only fatigues the eyes, but also damages and degenerates these retinal cells. The process in which blue light damages retinal cells starts with a retinal cell pigment called lipofuscin.
Lipofuscin is commonly known as the aging pigment in the body, and can be found in the retina, kidneys, liver and heart. In the retina, when lipofuscin absorbs blue light, it creates molecules called reactive oxygen species, or ROS. These dangerous molecules have been found to directly damage and decrease the viability of retinal cells.
You may be wondering, why is blue light so harmful? What about other colors/wavelengths of light? In comparing differing wavelengths of light, a research study discovered that illumination with green light, instead of blue light, resulted in substantially less damage to retinal cells; showing that the wavelength of blue light tends to be more harmful to retinal cells. It is thought that blue light is more harmful because of its location on the visible light spectrum. Blue light has a very short wavelength of 450-490 nm (very close to that of ultraviolet light), and thus emits very high levels of energy. So, it is likely that the high energy emission makes blue light so dangerous.
Since blue light has been found to have damaging effects on retinal cells, it is important to decrease the amount of blue light exposure we have on a daily basis. For instance, one research study suggests that blue light exposure is more dangerous in a dark environment, rather than in a lighted environment. These researchers found that rats exposed to blue light in the dark experienced 50% more visual cell loss, in comparison to rats exposed in the light. This shows that we should limit our use of devices such as cell phones, computers and televisions at night.
Lastly, it is thought that blue light blocking glasses lenses reduce blue light toxicity by a considerable amount, suggesting that glasses with blue light protective coatings can aid in reducing retinal damage from blue light. Similarly, apps on our phones and computers allow us to limit the amount of blue light they emit, which could be another option for controlling the amount of blue light we expose ourselves to.
If you still don’t believe that blue light is harmful, it has been linked to being a contributing agent in the development of two major sources of vision loss in the aging population: age-related macular degeneration (AMD) and age-related maculopathy (ARM). By wearing blue light protective lenses and limiting our exposure time, it is possible to slow the onset of AMD and ARM, along with any other retinal cell damage or eye fatigue. So, the next time you go to answer that late night text, make sure to think of your eyes first.