Online, there are a lot glasses claiming to block, filter or reduce blue light. Without clear criteria for comparison, it is difficult to assess the effectiveness of a pair. This brief article focuses on two tools to assess blue blocking glasses, both before and after the purchase. 

Before You Buy Blue Light Filter Glasses 

The first step is to identify why you want to filter blue light. If your primary purpose is simply reduce the glare on the computer screen then a free software like f.lux may do the trick.   

If you are looking to truly filter out blue light - then be sure to search for the transmittance spectrum of the glasses you're considering. The transmittance spectrum is a graph that that illustrates the percent of light passing through the lens and most retailers should make them available if requested. For...

New Study Shows that Filtering Blue Light Before Bed Improves Sleep of Adolescents

A study has shown that wearing blue blocking glasses in the evening "prevented light-induced melatonin suppression and alerting effects in young adults, and significantly improved subjective sleep quality after a continuous 2-week application"

The study was undertaken by Swiss scientists and published in the Society for Adolescent Health and Medicine. Researchers were attempting to assess if blocking blue light from multimedia devices would result in a measurable improvement in sleep promoting markers.

Details of the Study 

Thirteen healthy, male, high-school students between 15 and 17 years old were recruited for the study. Half the subjects were given blue blocking glasses and the other half given a clear lens (control group). 

The study was conducted in two phases : the preparatory period and the laboratory period. The first phase of the study lasted a week and...

Impacts of Backlit Devices on Teenagers

A new study shows that teenagers are more susceptible to impacts from use of backlit devices such as laptops and smartphones. The results of the study were published in the SAGE journal by the Lighting Research Center. 

If you know any teenagers - you already know that they are addicted to their phones. Actually, I should clarify that teenagers are probably just more addicted to their smartphones than everyone else. 

Before going onto the results of the Lighting Research Center it should be noted that smartphone usage among teenagers today is extraordinarily high. An alternate study conducted by Norwegian researchers on 10,000 adolescents between ages of 16 - 19 found that almost every single one of them used either a smartphone or laptop in the last hour before bed. (The duration of usage was not recorded). 

Now...

For millions of years we as humans had access to only two types of bright light - the sun and fire. That changed in the modern era with the invention of artificial lighting and the means to support its use.

The following infographic explores the growth of artificial lighting in our everyday lives and the steady growth of study of sleep as a science.  

Florescent bulbs and Light-Emitting Diodes (LED) lighting have become increasingly popular in recent years  - due to their lower cost and potential environmental benefits. However these savings come with a hidden cost.  While they have several benefits over old style incandescent bulbs you may have noticed that LED lights or florescent lights do not produce the same warm yellow color, instead producing isa whiter cooler light. This effect can be attributed to the type of light emitted - a lot more light in the violet and blue end of the visible light spectrum. Take a look at this comparison chart generated by Popular Mechanics. 

Image Credit: Popular Mechanics, 2015 

As you can see - the light produced by LED and CFL...

The use of a light emitting electronic device in the hours before bedtime can adversely impact us, a new study has found. Results show that blue light emitted by e-readers interrupts the body's natural circadian rhythm. This in turn causes reduced melatonin secretion, longer times to fall asleep and reduced next morning alertness. The study conducted by Brigham and Women's Hospital (BWH) who compared the biological impacts of reading a regular book to a book that had a back-lit screen. The findings were presented in the Proceedings of the Academy of Sciences on December 22, 2014. 

During the two week study, participants read either from a backlit e-reader or a regular printed book. Participants reading the e-reader took longer to fall asleep, were less...