Blue Filter Lenses for Eye Protection

A new CochraneEyes review of 17 studies concludes that glasses sold to protect eyes from blue light likely:

Nor do they prevent eye fatigue caused by cell phone and computer use.
Nor do they improve the quality of sleep.

Background

"Blue light filtering" or "blue light blocking" ophthalmic lenses prevent ultraviolet radiation and variable fractions of short-wavelength visible light from reaching the eye. There are several lenses on the market with blue light filters. It is claimed that they can improve visual performance with the use of digital devices, provide protection to the retina and promote sleep quality. The evidence from clinical trials on these suggested effects was investigated and potential adverse effects were considered.

Goals

To evaluate the effects of lenses with blue light filter compared to lenses without blue light filter, in improving visual performance, providing macular protection and improving sleep quality in adults.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (2022, Issue 3 ); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov and the WHO ICTRP. The last search in the electronic databases was carried out on March 22, 2022.

Selection criteria

We included randomized controlled trials (RCTs), with adult participants, in which ophthalmic lenses with a blue light filter were compared with ophthalmic lenses without a blue light filter.

Data collection and analysis

The primary outcomes were change in visual fatigue score and critical flicker fusion frequency (CFF), as continuous outcomes, between baseline and one-month follow-up.

Secondary outcomes included best -corrected visual acuity (BCVA), contrast sensitivity, bothersome glare, proportion of eyes with a pathological macular finding, color discrimination, proportion of participants with alertness, reduced daytime, serum melatonin levels, subjective sleep quality, and patient satisfaction with their visual performance. Findings related to ocular and systemic adverse effects were evaluated.

Standard Cochrane methods for data extraction were followed and risk of bias was assessed using the Cochrane Risk of Bias 1 (RoB 1) tool. The GRADE method was used to assess the certainty of the evidence for each outcome.

Main results

17 RCTs were included, with sample sizes ranging from five to 156 participants, and intervention follow-up periods from less than one day to five weeks. Approximately half of the included trials used a parallel group design; the rest adopted a cross -over design . A wide variety of participant characteristics were observed in all studies, from healthy adults to people with mental and sleep disorders.

None of the studies had a low risk of bias in all seven domains of the Cochrane RoB 1 tool.
65% of studies were considered to be at high risk of bias because outcome assessors were not blinded (detection bias) and 59% were considered to be at high risk of performance bias because participants and staff They were not blinded.
35% of the studies had previously been registered in a trial registry.
Meta-analyses of any of the outcome measures were not performed due to the lack of available quantitative data, the heterogeneous populations of the studies, and differences in the follow-up periods of the interventions.
There may be no difference in subjective eye strain scores with blue light filter lenses compared to non-blue light filter lenses at less than one week follow-up (low-certainty evidence).
One RCT reported no difference between intervention groups (mean difference (MD) 9.76 units [indicating worse symptoms]; 95% confidence interval (CI) -33.95 to 53.47; 120 participants) .
Furthermore, two studies (46 participants, combined) measuring visual fatigue scores reported no significant differences between intervention groups.
There may be little or no difference in CFF with blue light filter lenses compared to non-blue light filter lenses, measured at less than one day of follow-up (low-certainty evidence).
One study reported no signiﬁcant difference between intervention groups (MD - 1.13 Hz lower [indicating worse performance]; 95% CI - 3.00 to 0.74; 120 participants).
In another study, a less negative change in CFF (indicating less eye strain) was observed with high blue light filter lenses compared to low blue light filter lenses and non-blue light filter lenses.

Compared with non-blue light filter lenses, there is probably little or no effect of blue light filter lenses on visual performance (MCVA) (MD 0.00 logMAR units, 95% CI -0.02 to 0.02; one study, 156 participants; moderate-certainty evidence), and unknown effects on daytime alertness (two RCTs, 42 participants; very low-certainty evidence); Uncertainty about these effects was due to the lack of available data and the small number of studies reporting these outcomes.

It is not known whether ophthalmic lenses with blue light filters are equivalent or superior to lenses without blue light filters with respect to sleep quality (very low-certainty evidence).

Inconsistent findings were observed in six RCTs (148 participants); Three studies reported a signiﬁcant improvement in sleep scores with blue light-filtering lenses compared to non-blue light-filtering lenses, and the other three studies reported no signiﬁcant differences between the intervention groups. There were differences in populations between studies and a lack of quantitative data.

Device-related adverse effects were not consistently reported (nine RCTs, 333 participants; low-certainty evidence). Nine studies reported on adverse events related to study interventions; three studies described the occurrence of such events. Adverse events reported in relation to blue light filter lenses were rare, but included increased symptoms of depression, headache, discomfort while wearing glasses, and low mood. Adverse events associated with lenses without blue light filters were occasional hyperthymia and discomfort when wearing the glasses.

It was not possible to determine whether lenses with blue light filters affect contrast sensitivity, color discrimination, annoying glare, macular health, serum melatonin levels, or overall patient visual satisfaction compared to lenses without blue light filter, since none of the studies evaluated these outcomes.

Authors’ conclusions

This systematic review found that ophthalmic lenses with blue light filters may not attenuate symptoms of eye fatigue with computer use over a short-term follow-up period compared to lenses without blue light filters.
Furthermore, this review found no clinically significant differences in changes in FFC with blue light filter lenses compared to non-blue light filter lenses.
Based on the best evidence currently available, lenses with blue light filters are likely to have little or no effect on best-corrected visual acuity (BCVA) compared to lenses without blue light filters.
Potential effects on sleep quality were also undetermined, and included trials reported mixed outcomes among heterogeneous study populations.
There was no evidence from RCT publications regarding the outcomes of contrast sensitivity, color discrimination, bothersome glare, macular health, serum melatonin levels, or overall patient visual satisfaction.
Future high-quality randomized trials are needed to more clearly deﬁne the effects of blue light filtering lenses on visual performance, macular health, and sleep in adult populations.

Blue Filter Lenses for Eye Protection

Blue light filter ophthalmic lenses offer benefits for visual performance, sleep quality, and macular health in adults, suggesting potential applications in protecting eye health from the harmful effects of blue light exposure.