“Recently, the relationship between light and health has gained interest,” points out Dr. Kazuo Tsubota. In this context, several scientists, clinical researchers and practitioners are paying growing attention to the harmful effects of chronic light exposure, primarily to UV and blue-violet light. All experts are looking at further research to elucidate individual risk factors and bring clinical evidence through quality solutions. The common view, shared by Dr. Rowena Beckanham, is that “prevention is critical to ocular health management” and it will remain critical in the future.

THE ROLE OF SCIENCE:

the way ahead for research

The adverse affects of specific wavelengths of light, particularly UV, has been extensively covered in published research in the past decades. As Dr. David Sliney confirms, “there exists strong scientific evidence connecting the risks of cortical cataract and pterygium with UV (principally UV-B) radiation.” Although today, a significant body of work exists on both UV and blue light, there is further scope of scientific research in the days to come, especially on blue light. Encouraging researchers on this topic, Dr. Ralph Chou comments: “There is a lack of both basic and clinical scientific research into the ocular effects of optical radiation between 385 and 420 nm, and very little to follow up on the work published before 2005 on threshold exposures across the entire optical spectrum. We need a new generation of researchers in this field of study.”
At the same time, Dr. David Sliney emphasizes the need for more epidemiological studies on the subject. “Although most laboratory studies demonstrate the retinal phototoxicity of blue light, many epidemiological studies do not confirm an increased risk of age-related eye retinal pathologies,” he says. “Further research is needed to clarify why this contradiction exists.”

In academia, the association of certain wavelengths of blue light with circadian system has also come under discussion. It is an area of great interest that needs extensive scientific investigation. Dr. Kazuo Tsubota sheds some light on this: “We know that light governs the circadian rhythm, but have more recently learned that it is blue light, specifically, which controls this task. Intrinsically photosensitive retinal ganglion cells (ipRGCs), a third class of photoreceptors found in the retina of the mammalian eye in 2002, primarily recognise blue light and send signals to the brain. In other words, the eye not only sees, but also functions as a clock. We believe that disruption of the natural circadian rhythm through protracted night time usage of computers and smart phones disrupts sleep and can lead to depression among other health problems, and scientists also consider that blue light may aggravate eyestrain and dry eye. I am more convinced than ever that further research is necessary in this area.” 

“PREVENTION IS CRITICAL TO OCULAR HEALTH MANAGEMENT.”

THE ROLE OF CLINICAL PRACTICE:

patient education and prescription

Prioritizing the patient’s health and best interests, even with the progressing nature of scientific and clinical evidence, practitioners recommend educating patients on possible risks of UV and blue light and prescribing products that protect against these. Dr. Randall Thomas observes: “It is difficult to know with scientific certainty, but there is a growing body of science that indicates a health benefit to diminishing human tissue exposure to certain, specific wavelengths of visible blue, and ultraviolet light. It is likely prudent that we as clinicians do all that is practical and reasonable to protect the eyes of our patients by recommending eyeglasses that limit the amount of these wavelengths. Most certainly, the aggressiveness of such interventions will continue to be shaped with on-going research.”
Dr. Sliney encourages patient education as well. He adds: “The reduction of excessive short-wavelength, blue-violet light is prudent as extra ‘insurance’ against potential delayed effects upon the retina. Clinical practice should serve an educational role in promoting UV protection for their patients, including peripheral (temporal) protection by frame design. Reducing short-wavelength light exposure may also be beneficial – particularly in bright daylight and in some domestic light sources.”
Dr. Walter Gutstein feels protection against UV and high-frequency violet light is going to become a standard in the future, “As far as the retina is concerned, we know that the blue receptor is always affected first. Unfortunately, if this receptor is damaged it would further lead to significant impairment. Not only this receptor displays blue and yellow but it is also majorly responsible for contrast regulation. Damage to this receptor is much more noticeable than to all other photoreceptors even though it varies from one person to another depending on several conditions. Evidently, protection from both UV and high frequency blue-violet light should become a standard in coming years.”
When educating patients, attention should also be given to life style choices and occupation. “Eye care practitioners have a fair amount of knowledge on the adverse effects of UV radiation and blue-violet light on the eye,” explains Dr. Ralph Chou. “They should educate their patients on how occupational and lifestyle exposure to optical radiation can be reduced or modified to prevent future ocular health problems, and prescribe appropriate eyewear as well.”

NEXT STEPS: 

clinical evidence for preventive eyewear

Clinical evidence of eyewear performance helps convince patients greatly of their benefits. As a practitioner herself, Dr. Rowena Beckanham strongly urges the need for this. She argues: “As practitioners we need a strong evidence base to show consumers the benefits of new coatings and lenses to enable performance in a fast changing digital world. We need clinical trials published in reputed journals that stand up to the rigor of the scientific community to show the risks of increasing blue light exposure:
a. risks to macular health;
b. the use of digital technology and

“PROTECTION FROM BOTH UV AND BLUE-VIOLET LIGHT SHOULD BECOME A STANDARD IN COMING YEARS”

visual fatigue;
c. interference with sleep patterns in sleep deprived teenagers with overuse of digital technology.”

In practice, there is still very little known on the eyewear options and the role of the lens coating in filtering out UV and blue-violet visible light. “Although it is generally understood that sunglasses provide ocular protection from potentially harmful ultraviolet (UV) radiation, what is less known is the importance of the lens coating quality, filtration properties and fitting geometry. When treating patients, eye care professionals should explain the potential consequences of shortand long-term exposure to UV, as well as offer well-fitting treatment options that adequately filter UV and other potentially harmful short-wavelength visible light,” says Bret Andre. From his perspective, “further research isolating visible light wavelengths that cause ocular damage will assist lens designers to optimize protective lenses without sacrifice to visual function.”

Survey conducted by Anwesha Ghosh