For this blog post I’m doing a Q&A with an expert on the topic of blue light.  I’m a big believer on the adverse effects of blue light on vision, metabolic, and mental health in adults and children.  It definitely used to be a major sleep disruptor for me until I started getting far more disciplined with limiting/eliminating it before bedtime.  Some of us are so habituated to the impact of blue light that we can’t even recognize what it’s doing to our overall health which is concerning.  

Dr.Parveen Jaglan, OD
Dr.Parveen Jaglan, OD

In today’s Covid-19 environment, we need to view blue light as a drug that adults and children are overdosing on because work and school have shifted predominantly onto screens. 

Dr.Jaglan is an optometrist who has the benefit of being both a clinical practitioner in practice for over 23 years and someone who has done deep research in the area of blue light and its impact on adults and children.  As a result of her journey, she has patented a blue light coating designed to protect while decreasing eye strain due to overexposure to digital devices.  

Dr.Jaglan developed one of the first over the counter blue light protection glasses on the market called BLEP (Blue Light Eye Protecgtion). Her blue light glasses, BLEP Eyewear won first place award for Best Medical Device at the Southeastern Medical Device Association in 2015.

Disclaimer:  I have no financial affiliation with BLEP Eyewear, but I was sent free samples of eyeglasses to try.  I’ve experimented with several brands and even called companies with mostly unsatisfactory responses to my questions about wavelength-specific eyewear, which as you’ll learn is critical.  I find these glasses to be the best, the most economical, and they have real science backing them along with a founder who is a passionate practitioner and pioneer in the field.

Blue Light Q&A

The health impact of blue light, can you give us your perspective on blue light on adults?

Blue light is very important and plays a crucial part for humans. Blue light is what controls our circadian rhythm cycle, which is critical for keeping our metabolic system in balance. Having a good night sleep is important in keeping our cortisol levels in check because it affects our weight, stress, and immune response.  

Due to the scattering nature of blue light, it causes eye strain and headaches. Lastly blue light reaches the back of the eye in contributing to age related macular degeneration. 

Are there unique issues we need to worry about in children, especially in our pandemic world?

That is an important question because the kids today are developing in a very different visual environment  than any humans have in history. We are becoming more of an indoor society and this is affecting kids, especially during developmental stages of their life.

The eye emmetropization (the process of eyes having perfect vision) starts at the first sight of light. The human eye is conditioned to develop being exposed to the full spectrum of light that the natural outdoor sunlight provides.

As we keep our kids more indoors and in front of back lit led devices, we are seeing more nearsightedness.  It is predicted that 50% of the world will be nearsighted by 2050.

We are also seeing an increase in diagnoses of ADHD. If kids don’t get a good night’s sleep because they are on their digital devices before they go to bed, they can’t concentrate the next day, causing attention issues. We as practitioners understand that in our current culture we can’t completely ban our kids from digital devices.

Our recommendation is ages 0-5 minimal to no digital device usage. After age 5 frequent breaks every 30 min with the balance of outdoor activity.

Create a kids home work/play environment near windows and allow exposure to as much natural light as possible. All digital devices turned off 1 hour before bedtime. If this is not possible for teenagers that study well into the late evenings, turn on night modes on their digital devices and/or get them some proper blue light glasses. 

We can go on and on about outdoor not only being important for the eye but the entire body. Our levels of vitamin D are decreasing as a society which plays such an important protective role with our immunity. The key for our kids is to find a balance.

Can you explain in layman’s terms how exactly blue light exerts its adverse effects and the concept of wavelengths?

Blue light has three main factors when it comes to eyes.

1. Blue light affects sleep. If you are on your digital device before you go to bed, your body thinks the sun is still out and your melatonin doesn’t get produced at optimal levels which will affect how well you will sleep.

2. Blue light is the most scattering of all wavelengths. This explains why we see the sky as blue most of the time, since blue light travels as shorter, smaller waves than other colors.  Our eyes are not designed to focus on blue light so our eyes are constantly straining trying to focus on this light causing eye strain. When you are looking at paper, the source you are looking at is constant and the background light is constant.  Your pupil only reacts one time.

When looking at pixels and different screens, your pupils are constantly reacting, causing accommodative eye strain.

Also led light work on a pulse width modulation, the brain recognizes this pulsing and over 10% of the population get headaches from led and/or overhead fluorescent lights. 

3. Blue light reaches our macula (the critical part of our retina responsible for detailed vision).

Overexposure to blue light leads to macular degeneration. 

Unlike UV which the front of the eye has some natural defense against, blue light goes to the back of the eye. Even though blue light from digital devices is but a fraction of the intensity compared to outdoor blue light, we are still spending 8-10 hours, 20 inches from our faces, year after year. Our concern is what will this look like in 30 years. We have some lab studies of damage to retinal cells from indoor blue light but we don’t have long term human data on this yet due to this being a relatively new issue.

Wavelength is important when it comes to blue light. UV is from 100-400nm and is an invisible spectrum. Blue light is from 400-500nm and is part of the visible spectrum. So it is impossible to block blue light wavelengths by large percentages without affecting the vision. This is why one cannot see out of solar eclipse glasses, they block blue light by 100%. All back lit led digital devices emit blue light at a very narrow spectrum peaking at 450nm. They have little to no blue light emission at let say 400-410nm. 

There are countless companies out there pitching all types of blue-light blocking glasses and it is really difficult to find which products are truly effective.  How do we choose?  

This is a challenging question because unfortunately there is a lot of misinformation out there and companies are taking advantage of this lack of layman knowledge on this relatively new topic. I would stay away from any company that advertises 50% or above in blocking blue light because we know one cannot effectively do this without also affecting vision. Most companies block blue light at around 405nm which is really the tail end of UV light and it is easier to do but unfortunately doesn’t do much in helping against blue light from digital devices. My advice would be to try and find out exactly at what wavelengths they are blocking and if they can give you any data regarding this. 

The key is that the product has to block at around 430-470nm because blue light from digital devices only emits in this range, peaking at 450nm.

Preventing macular degeneration and helping headaches, especially from concussions, happen by blocking at 460nm. So products that are wavelengths specific will be the most effective. 

Can you break down the impact of different commonly used electronic devices (smartphones, Ipads, laptops, desktops, TVs, etc.)?

Generally it’s always better to view things at a further distance. The closer you hold your material, the more your eyes have to work to bring the objects into focus. This becomes more apparent as you reach the age of 40 and older. Even moving things away by a few inches makes a big difference in reducing how much work your eye does. 

Do you recommend wearing these glasses all day and for evening work or in the evening only?  Some studies report blue light exposure, even from screens during the day may help circadian rhythm, so would blue light reducing glasses  prevent those potentially beneficial daytime effects? 

The recommendation is if you are going to do more than 30 minutes of digital device work,  especially in the evening, you should wear blue light protective glasses. If you are on and off and are on digital devices for short spurts, it is not needed. I don’t feel wearing blue light glasses during the day has any negative effect on the circadian rhythm.

Most good blue light glasses on average block about 20-25% of blue light in the narrow spectrum, meaning they don’t block in the entire spectrum of 400-500nm.

So you are blocking only a certain percentage of excess blue light in a narrow spectrum that your eyes are overexposed to in front of digital devices. This further emphasizes the importance of wavelength specific glasses.  Blue light glasses become very important at night as it reduces that narrow spectrum of blue light from digital devices, allowing your melatonin to be produced.

Apart from glasses, are there other tools or behavior changes you recommend to preserve vision and reduce the impact of blue lights and screen time on your eyes?

Apart from being overexposed to digital blue light and its effect on our eyes as discussed above, most people that spend endless hours in front of screens suffer from computer vision syndrome. This entails dry eyes…our blink reflex is reduced when we do near work, eye strain due to excessive focusing work the eye has to do at near…the lens inside our eyes are designed to be relaxed when viewing distance objects and flex when viewing objects at near.

Also we get complaints of shoulder and neck pain from stress of head tilt when viewing laptops and other digital devices. Human species weren’t designed to do near work for 7-10 hours at a time. The best way to alleviate this is by taking frequent breaks.

We have a catchphrase, 20/20/20, where every 20 minutes you should look at objects 20 feet away for 20 seconds.

We don’t expect one to do this exactly but it is a reminder that we need to take frequent breaks and allow eyes to relax by looking far away. Get out of your chair and walk up to a window and stretch. It is also great to use over the counter lubricating eye drops a couple of times during the day, if you know you will be doing excessive computer work. 

Do you have any personal or patient stories to share regarding the impact of these types of glasses on common health issues like insomnia and headaches?

Yes we have had several patients tell us that after wearing our BLEP Eyewear, it is the first time they have slept well in years. Our eyewear has a strong following by post concussion patients because of the amount of headaches it reduces. By decreasing some of the scatter of blue light from digital devices, we increase the contrast helping in reducing eye strain. 

I have lots of patients who are high-stress workaholics and my worry is that even with the best set of blue-blocking glasses on, they will still be working too late at night and not give their minds time to wind down.  What are your thoughts on this?  Are blue-blocking glasses sufficient to counteract late-night screen habits? 

I agree with you on this. Blue light glasses work in assisting with reducing some of the negative effects of blue light but because it is part of the visible spectrum you can’t eliminate it. We still have to do what our body organically needs to help keep our wake/sleep cycle intact. When we can, we have to  shut down at least 40min-1hour before bedtime.

I always believe that we have to look at how nature is supposed to work when it comes to the wellbeing of the human body. 

I think in general we underestimate the health issues we can reduce by simply destressing and getting a good night’s sleep. We have a very demanding culture and it is very easy to forget the stress one puts their body through. We have to remind ourselves that how gracefully we will make it to the finish line depends on how healthy we keep our mind, body, and soul.

Thank you Dr. Sinha for the opportunity to speak about a topic I am very passionate about. I hope there were some easy take home points for your viewer and their families.  If nothing else, remember 20/20/20 and sleep well.

To order BLEP eyewear for you and your family and to learn more about blue light, visit their website here.


Blue light phototoxicity toward human corneal and conjunctival epithelial cells in basal and hyperosmolar conditions

Blue light effect on retinal pigment epithelial cells by display devices

Role of short-wavelength filtering lenses in delaying myopia progression and amelioration of asthenopia in juveniles