A study published in Optometry and Vision Science concluded that blue light filters are no more effective at reducing the symptoms of digital eyestrain than an equiluminant neutral density filter.
Researchers said they undertook the study due to little evidence to support claims from eye wear manufacturers that blue-blocking filters can reduce the symptoms of digital eyestrain (DES).
“The impact of blue light on the eye has gained increased interest in recent years owing to the high proportion of these wavelengths emitted by light-emitting diodes,” the authors wrote. “These are commonly found in digital screens such as desktop, laptop and tablet computers; electronic reading devices; and smartphones.
“This is particularly pertinent nowadays given the substantial number of hours being spent by many (or perhaps most) individuals viewing these screens in contemporary life,” they continued. “In addition, there is a high prevalence of both ocular and visual symptoms associated with viewing these displays.”
Researchers used digital screens overlaid with either a neutral density (ND) filter, for the control group, or a blue blocking (BB) filter, both of equal luminosity, according to the study. They had 23 young adults perform a 30-minute reading task with these screens. Subjects were measured for accommodative response, pupil diameter and vertical palpebral aperture dimension at 0, 9, 19 and 29 minutes. After the reading task, subjects completed a DES questionnaire to quantify symptoms.
Co-author Mark Rosenfield, MCOptom, PhD, FAAO, professor diplomate in binocular vision, perception and pediatrics at the SUNY College of Optometry, and his colleagues showed that a BB filter was no more effective at reducing symptoms of DES than an equiluminant ND filter.
“These results do not support the use of blue-blocking filters for the treatment of digital eyestrain. Individuals suffering from this condition should receive a complete ocular evaluation, including refractive error, binocular vision, oculomotor and ocular surface assessment to determine the health of the eye,” Rosenfield told Primary Care Optometry News.
“In addition, they should be counseled regarding appropriate ergonomics and environmental issues when viewing electronic devices for a sustained period,” he said. “Factors such as appropriate viewing distances and gaze angles, the need for frequent breaks and avoidance of glare and screen reflections should also be emphasized.”
According to the study, while BB filters were not shown to reduce any apparent symptoms of DES, scientists acknowledged that it remains unclear why blue light should cause DES symptoms in the first place. Additionally, this study neglected to show that BB filters did not protect eyes from other potential effects of blue light on eyes.
“[T]here is no physiological mechanism at the present time that links blue light with eyestrain,” Rosenfield said. “Blue light may interfere with the body’s circadian rhythm, so that blue light exposure in the evening may interfere with the ability to go to sleep. It is for this reason that digital screen time should be avoided in the 1 to 2 hours before bedtime. Also, extremely high levels of blue exposure may be associated with damage to the posterior segment and has been linked with conditions such as age-related macular degeneration.”
Rosenfield and colleagues have conducted further research on this topic. Their latest conclusions appear to support the results of this study.
“More recent work from our laboratory (submitted for publication) also found no significant difference in symptoms of digital eyestrain between clear lenses that included a blue-blocking filter and a clear CR39 lens. Accordingly, there is little support for this treatment paradigm at the present time.” – by Scott Buzby
Disclosure: None of the authors reported any relevant financial disclosures.