Blue Light and How to Block It - Overnight Glasses

Blue Light: Everything You Need To Know

What is Blue Light?

Blue light is part of the visible light spectrum with a wave length range of 380-500 nano-meters (0.000000001 m). Blue light is located on the shorter wave length of the visible light spectrum, therefore blue light caries higher amount of energy that according to new findings can cause extensive and long term damages to the eye.



Previously, human eyes were exposed to blue light only as a part of the visible light spectrum that naturally exists in sunlight which is essential for us to function normally. Today, due to the substantial advancement in technology, humans are exposed to additional sources of blue light that is emitted by most electronic screens and LED lights. Massive integration of modern communication devices and computers into our daily activities may cause overexposure and subsequent damages to the eye and other disorders arsing from overexposure to blue light.


In the past, Exposure to Blue Light was solely from natural sunlight.


Possible harmful effects of overexposure to Blue Light

Most of us are familiar with another natural part of sunlight – U.V (Ultraviolet) light which positively help regulate many of our body functions such as production of vitamin D, which is essential in maintaining healthy skin and a positive mood. Overexposure to U.V on the other hand, is also well documented and most of us are aware of its negative effects such as skin burns, eye cataract, ‘snow blindness’ and different types of cancer. Due to this awareness, today most of eyeglasses and sunglasses lenses materials and coatings provide protection from U.V light.

Blue light research is a relatively new, but there are already available studies showing that exposure to blue light is essential in creating normal circadian rhythm in mammals. The circadian rhythm mechanism is related to production of melanopsin, a protein that is being produced in specific photosensitive cells located in the retina. As such, the natural blue light is essential for us to have normal sleep and wake cycles.  

As mentioned above modern life activities may be the source of overexposure to blue light and can cause severe health disorders that are listed below, but are not limited to:


Digital Eye Strain

The first, and most noticeable health issue associated with over exposure to blue light, is Digital Eye Strain that can cause blurry vision, headaches, dry eyes, and even neck and back pains. These symptoms have been increasingly reported, and today digital eyestrain became more known as the number one issue associated with computer work.


Disruptions of sleeping patterns

Excessive exposure to blue light may disrupt a normal production of melanopsin which is required to maintain regular wake and sleep cycles. Our eyes are made to respond to a normal 24 hour cycle and serve as the primary conduit of light signals to the brain. Exposure for longer periods of blue light than our brain perceive as normal, can increase the time it takes us to fall asleep and can also result in abnormal sleep cycles.


Age-related Macular Degeneration symptoms

Prolonged exposure of the retina to extensive blue light may cause damage to our light sensitive retina cells which will result in symptoms similar to age-related macular degeneration (AMD) and cause severe vision deterioration.


Overexposure to blue light may lead to Digital Eye Strain, Abnormal sleep-wake cycles and Macular Degeneration.


How to protect your eyes from overexposure to blue light?

It is clear that as humans living in this technological era, one can hardly avoid overexposure to the increasing amounts of blue light. It was found that users of blue light blocking eyeglasses lenses reduce digital eyestrain by half, and could be rightfully assumed that other related negative health effects of overexposure to blue Light will be reduced as well.


Blue Armor Lenses

Overnight Glasses offer to its customers’ high performance Blue Armor™ lenses that were developed specifically to substantially reduce the amounts of blue light energy absorbed by the retina. In difference from other blue light filtering lenses available in the market, Blue Armor Lenses are clear (None tinted), do not affect/reduce normal vision, while maintaining blue light blocking capabilities that according to certified third party tests, are exceeding all of ANSI Z87.1 Blue Light safety standards.


Check size on your frame

Most frames have size displayed on the inside of the frame arm

Or use a ruler

Use a ruler to measure your existing frame as shown below. Frame sizes are measured in millimeters, so you need to use a ruler that is marked in centimeters and millimeters. If you don't have millimeter ruler, you can click here to print it, or take measurements in inches. Note that measurements in inches need to be taken with the precision of 1/16 (one half of 1/8 if your ruler does not have more precise markings)

I got it! Here is My Size


Measure your PD

In some cases your vision correction doctor may forget to give you your PD (pupillary distance). The best option will be to ask your doctor to measure it. It is part of your prescription and an eye doctor needs to provide it.

If this is not possible, you may use the methods listed below.

The easiest way:
1) Wear any glasses with clear lenses.
2) Use a mirror or ask a friend or family member to mark your pupil location on the clear lenses using a dry erase marker. They must stand in front of you and be at the same height as yours. If you use a mirror make sure you stand 3ft from the mirror and your general stare is directed to the center of the glasses.
3) Using a ruler with a millimeter range, measure the distance between the two dots and that’s your PD

If you don’t have in your possession glasses with clear lenses, you may measure your PD using this method:
1) Obtain a ruler with millimeter values
2) Place the ruler horizontally on your nose bridge, zero slightly below your right eye;
3) Ask a friend or use your mirror to see the distance on the roller. The distance measured is your PD.

Although we don’t recommend this option, if you are unable to use the methods above, you may use the general PD for: Women 62 and Men 64.