This article is more than 5 years old. Information may no longer be current.

Popularity of electronic devices, ‘greener’ light bulbs increases blue light exposure

Experts say this wavelength can damage the retina and disrupt circadian rhythms.

Issue: October 2012

Add topic to email alerts

Receive an email when new articles are posted on

Please provide your email address to receive an email when new articles are posted on .

Subscribe

Added to email alerts

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

Back to Healio

We were unable to process your request. Please try again later. If you continue to have this issue please contact customerservice@slackinc.com.

Back to Healio

While eye care providers have successfully been protecting people from ultraviolet wavelength light, they may be overlooking a wavelength that can have just as serious, if not more serious, ocular consequences: blue light. 

“We are now exposed to an unprecedented amount of blue light,” Gary L. Morgan, OD, said in an interview with Primary Care Optometry News. “All of our digital devices are backlit by either fluorescent or LED bulbs, which have a high blue spectral emission. These digital devices are often held close to the eyes, increasing the amount of blue absorption.”

While ultraviolet (UV) wavelengths can contribute to lid cancers, pinguecula, pterygia or cataracts, in general, people in the U.S. do not go blind from these conditions. However, blue wavelength light causes oxidative retinal damage that can lead to age-related macular degeneration, which can result in blindness, Morgan said.

“Our society could be facing an unprecedented public health crisis in the form of vision loss if the magnitude of blue light exposure continues unchecked,” he said.

More immediately, nocturnal exposure to blue light, such as that emitted by devices people continue to use after the sun goes down (iPads, smart phones, computers, televisions, etc.), causes disruptions in people’s circadian rhythms, which regulates sleep patterns.

Gary L. Morgan

Blue light suppresses melatonin

According to a recent Harvard Health Letter, blue wavelengths — which are beneficial during daylight hours because they boost attention, reaction times and mood — seem to be the most disruptive at night. While light of any kind can suppress the secretion of melatonin, blue light does so more powerfully. 

Michael Tolentino

“Melanopsin-expressing retinal ganglion cells contain the photopigment melanopsin that is particularly sensitive to blue light,” Morgan said. “Researchers believe these cells regulate our internal clock, giving us a sense of night and day, and even time of year. Blue light exposure signals the pineal gland to suppress melatonin secretion, our sleep hormone, which tells us to stay awake during daylight hours; likewise lack of blue light signals the gland to secrete melatonin to induce sleep.”

A study published in the Journal of Applied Physiology found that the light emitted by computer screens affects circadian physiology, alertness and cognitive performance levels.

“The LED-backlit screen emitted 3.32 times more light in the blue range between 440 nm and 470 nm than the non-LED-backlit screen,” the study authors found.

The Harvard Health Letter also cited several studies that have linked working the night shift and blue light exposure to an increased incidence of cancer, diabetes, heart disease and obesity because of an alteration of the circadian rhythm.

Inadequate natural defense

According to Michael Tolentino, MD, a member of the Primary Care Optometry News Editorial Board, the body has its own natural defense against blue light wavelengths, but it is not enough to combat the recent across-the-board increase in blue light exposure from the plethora of electronic devices and the movement for “greener” energy.

While fluorescent light bulbs and LED lights are much more energy-efficient than incandescent lights, the Harvard Health Letter said, they also tend to produce more blue light. That means the proliferation of electronic devices with screens, as well as energy-efficient lighting, is increasing our exposure to blue wavelengths, especially after sundown.

“Patients who develop cataracts with mainly an upregulation of ocular lens pigment do not perceive an alteration in their vision,” Tolentino told PCON. “In essence, evolution has chosen ocular lens pigment as a way of protecting against blue light damage without the deleterious psychophysical changes that would be produced by typical blue blocking strategies.”

However, there are problems with this natural defense that current trends in round-the-clock blue light exposure are exacerbating, he said.

“First, even when patients develop cataracts, the development of brunescence is a slow, multi-decade process that allows for chronic blue light exposure that results in irreversible cumulative damage to the retina and posterior pole cells that lead to the progression and development of macular degeneration,” Tolentino said. 

Second, the natural amount of ocular lens pigment is only able to block a short period of intense blue light in a day, which is why northern Europeans, who are exposed to both a lesser magnitude and a lesser duration of daylight, have less ocular lens pigment than races living near the equator, he said.

“Third, no eyes have evolved to handle nighttime blue light exposure, and with the advent of energy-efficient lighting, we now have the potential to have 24-hour exposure to it,” Tolentino said.

“We are currently performing an unprecedented experiment on the human race by changing our indoor lighting sources from incandescent energy-inefficient light bulbs to energy-efficient blue light-predominant light bulbs,” Tolentino said.

Blue light is important in the pathogenesis of AMD, he said. It can cause photo-oxidation, which converts lipofuscin into an epoxide and increases the formation of malondialedehyde. It is for this reason that people who are predisposed genetically to AMD should protect their eyes from blue light, he said.

Full-spectrum lighting

Full-spectrum lights, touted as emulating sunlight’s natural exposure, are often recommended for patients with failing contrast function, including patients with age-related macular degeneration.

These lights “absolutely contribute to blue light exposure,” Morgan said, “and, in my opinion, should be avoided by those with AMD or those at risk. While they are brighter, and brighter light may allow for better vision, they are dangerous due to their spectral transmission.”

Morgan said a halogen lamp with a dimmer may be an option to full-spectrum lights. Also, a new spectacle lens that filters blue light (Blu-Tech by Eye Solutions) would be an option, because “filtering enhances contrast sensitivity in patients with a compromised macular retinal pigment epithelium or photoreceptors,” he said.

An option for filtering blue light

At Vision Expo West, Eye Solutions introduced the Blu-Tech Lens, an indoor and nighttime spectacle lens designed to protect the eye from blue and UV light. 

Eye Solutions Chief Executive Officer Greg Naes told attendees at a press conference that, in the past, sunglasses have been made available to block blue light, but they often affected the wearer’s color perception. The ocular lens pigment in the Blu-Tech lens blocks UV and filters blue light without changing color perception, he said.

He noted that children and post-cataract surgery patients have no protection against blue light. 

“The Blu-Tech lens has true medical necessity,” Naes said.

The lenses will be available before the end of the year through Signet Armorlite in single vision, flat-top bifocal and free-form back surface progressives. – by Daniel R. Morgan