Blue-blocking, neutral density filters equally effective for dry eye

CHICAGO – A neutral density filter was as effective as a blue-blocking filter at reducing symptoms of digital eye strain, according to a study presented here at the American Academy of Optometry meeting.

Student Tatiana Palavets and Mark Rosenfield, OD, PhD, FAAO, of the State University of New York College of Optometry, evaluated 24 young, visually normal subjects who read from a tablet computer for 30 minutes.

The digital screen was overlaid with either a neutral density filter that reduced intensity across all spectrums or one that eliminated 99.9% of emitted blue light (wavelengths between 400 nm and 500 nm), providing equal screen luminance.

According to the study, accommodative response, pupil diameter and vertical palpebral aperture dimension were measured at baseline and 9 minutes, 19 minutes and 29 minutes after the start of the task.

Palavets told Primary Care Optometry News that, afterwards, patients answered questions regarding blurriness, dryness, irritation, tiredness, sensitivity and discomfort.

“Symptom scores were about the same, and no signs were different in accommodation,” she said.

The mean total symptom scores were 42.83 for the blue-blocking filter group and 42.61 for the neutral-density filter group, according to the study. Pupil diameter, accommodation and vertical palpebral aperture dimension showed no significant differences between the two groups.

“Blue light blocking works about the same as reducing the luminance,” Palavets said. “Blue-blocking filters have no scientific background.

“I would not recommend blue-blocking filters specifically for computer symptoms,” she told PCON. “I would recommend a desktop humidifier, visual hygiene and following the 20-20-20 rule: look at something 20 feet away for 20 seconds every 20 minutes. If patients complain about glare, anti-glare works.”

An anti-glare filter would also help with accommodation, Palavets said.

“If doing a prolonged task, you blink much less, contributing to dryness,” she said. “All of these things will help reduce symptoms of digital eye strain. It is usually believed to be caused by something coming out of the screen. It’s not linked to that directly.” – by Nancy Hemphill, ELS, FAAO

Reference:

Palavets T, Rosenfield M. Effect of blue-blocking filters on digital eye strain. Presented at: American Academy of Optometry; Chicago; Oct. 10-14, 2017.

Disclosure: Palavets received a Johnson & Johnson travel grant to present her poster at the meeting.