With all the time spent on screens during the COVID-19 pandemic, blue light-blocking spectacle lenses have become more popular than ever before. However, eye care providers are quick to point out that while these glasses may increase subjective comfort, the amount of blue light emitted from screens isn’t enough to cause permanent damage to the retina, nor is it the blue light source patients should be concerned about (that would be the sun). More often, screen-related ocular discomfort stems from factors such as decreased blink rate and long hours of eye strain.

On the other hand, blue light-blocking glasses may provide some relief for those who suffer from migraines (as blue light activates a trigeminal nociceptive pathway through an intraocular mechanism) or help those attempting to mitigate the effects of blue light on their sleeping schedules.1

One recent study noted that while these blue light-blocking lenses are widely promoted by their manufacturers and practitioners, their effect on color vision is unknown. The researchers stated at the outset that “before recommending tinted lenses to patients, practitioners should bear in mind any effects on color discrimination.”2

The study measured the transmittances of commercially available lenses, and researchers selected the three lenses with the lowest blue light transmittance. Study participants took three computer-based color-vision tests: Colour Assessment and Diagnosis, the Cambridge Colour Test and the Farnsworth-Munsell 100 Hue Test.2

Among the three lenses, the reduction in blue light transmittance varied from 12% to 40% (2% to 30% compared with an untinted lens). The researchers found no statistically or clinically significant effect on any of the three color vision tests. They concluded that the modest amount of blue light reduction the lenses provide didn’t significantly affect color vision.2

1. Okamoto K, Tashiro A, Chang Z, et al. Bright light activates a trigeminal nociceptive pathway. Pain 2010;149:2:235-42.

2. Baldasso M, Roy M, Boon M-Y, et al. Effect of blue-blocking lenses on colour discrimination. Clin Exp Optom. October 8, 2020. [Epub ahead of print].