Blue-Light Filtering Spectacles Modestly Reduce Hazard

Woman Holds Sunglasses Against Sky
Close-up of woman’s hand holding sunglasses against sky with view of sun through lens
The study shows that tinted glasses performed slightly better than the coated lenses.

This article is part of Optometry Advisor’s conference coverage from the 2021 meeting of the American Academy of Optometry, held in Boston from November 3 to 6, 2021. The team at Optometry Advisor will be reporting on a variety of the research presented by the primary eye care experts at the AAO. Check back for more from the AAO Optometry 2021 Meeting..

Our ever-digitized world has our eyes awash in the blue light (400-460 nm) that has been associated with a variety of ocular and visual pathologies. A study presented at the American Academy of Optometry 2021 meeting in Boston, held November 3-6, reviewed the potential increase in exposure to blue light that can be attributed to devices such as smartphones screens and modern room lighting and how blue-light filtering spectacles can potentially reduce its harmful effects.

A team of investigators associated with the Autonomous University of Sinaloa analyzed patients who wore 4 different blue-light filtering glasses, with no added dioptric power. They offered patients 2 coated-lens options, the Crizal® Prevencia® (Essilor) and the Blue Protect® lenses (Zeiss), as well as 2 tinted-lens options, 1.60 UV BLUE LIGHT (Vaccutek), and Anti Blu-Ray lense (Seto).

The investigators used a calibrated photodetector and spectrophotometer to measure the spectral radiance of 64 smartphones (AMOLED and LCD), 54 light bulbs (cool and warm LED, cool and warm compact fluorescent lamps and incandescents), and 2 phototherapy (Bilitron and PhT 4000). They analyzed each light source and each lens’s ability to block ultraviolet (UV) A, UV B, and blue light.

The study found that smartphones have a blue hazard increment of 72%, relative to incandescent light bulbs, whereas cool LED and cool CFL lamps have an increment of approximately 31%. Phototherapy light sources also increase the relative blue hazard from 9 (PhT-4000) and 93 (Bilitron) times compared with standard incandescent bulbs. 

The spectacles almost completely blocked UV A and UV B rays. All the blue-light filtering glasses reduced the calculated blue-hazard by 1% to 16% compared with clear lenses. The reduction of blue-light hazard due to the 3 kinds of light sources by wearing the blue-light filtering glasses presents a small variation among them. The 2 tinted options provided slightly better reductions in the blue-light hazard compared with the coated spectacles. 

Blue-light blocking spectacles can reduce an important amount of UV light, according to the study’s conclusion. However, their performance in the filtering blue-light between 400 nm and 460nm is “modest,” researchers said. “We believe that an improvement in reduction of the amount of blue-light could be achieved without losing other important photobiological properties.”

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Teran-Bobadilla E, Yee-Rendon C, Acuña-Maldonado R. Blue hazard modest reduction by wearing blue light filtering glasses. Poster presented at the American Academy of Optometry 2021 meeting; November 3-6 2021; Boston. Board #75.