scientific facts :
- Laptop, Mobile & LED bulbs emit harsh blue light.
- Sleep difficulty at night is associated with blue light exposure.
- Can pose risk to Retinal, Corneal and Crystal lens of the human eyes.
- Non colored lenses block 20% and Amber lens (yellow) can block up to 100% blue light.
Roughly 70% buyers in India end up purchasing non-colored blue cut lens for computer eyewear which does not block significant amount of blue light. Reason is that optical market is flooded with cheap clear lenses and there is lack of information & knowledge among buyers.
Guidance provided by opticians is also most of the times flawed as problems caused by digital screens is something which is very new.
Blue cut lenses reduce blue light exposure
There are 2 primary methods to reduce the blue light exposure:
- Method 1 – Do not work on digital screens – First method is to avoid the use of mobile, laptop and other digital screens. Some people practice digital-detoxification method which is a great way to refrain from digital screens.
Digital detoxification greatly helps in relieving the eye strain and also cuts down the blue light exposure. This method sounds simple but since it requires a strong willpower & patience to stay away from addictive facebook feeds, whatsapp messages & youtube videos, it is barely practical to practice digital detoxification. When someone experiences immense eye discomfort in front of digital screens then it is the first thing to completely stop using them.
- Method 2 – Wear eyeglasses with blue cut lenses– A person whose bread & butter is dependent on technology can not think of working on paper. A programmer can not compile & run software programs on a paper. In order to share the news of rank promotion, with his mother who lives in a different city, he will use a smartphone instead of writing a postal letter.
So the second method which is widely accepted is to wear blue cut glasses or blue light blocking glasses. Such glasses are equipped with special optical lenses which do not allow the blue light to pass through the lenses into the eyes.
Mobile & Laptop screen produce blue light
- Almost all modern screens are lit up by small LED bulbs. These tiny bulbs produce light and that light has all colors like Violet Indigo Blue Green Yellow Orange Red. Out of all these colors blue portion is the most harsh.
- Blue portion of the light is a cause of concern for those who spend long hours in front of digital screens. This is so penetrative that the natural lens of our eyes do not block and it reaches the retina.
- Eye strain, headache, sleep disorder and eye dryness has become a common problem for all technology users. You will agree that all such problems are not just irritating but also reduce the work efficiency drastically.
Great lesson from a woodcutter about blue light
- Saw (आरी) is the name of the tool which a woodcutter or lumberjack uses to cut the wood. Right ?
- What is the mechanism in that Saw tool ? It has teeth. Shorter the distance between two teeth, better it cuts the wood. It can even cut iron if the teeth are tiny, more frequent and in little distance from each other.
- Exactly similar phenomenon takes place in the light spectrum. Blue waves are more frequent and short distant. In terms of science, blue light has short wavelength and high frequency.
Can a woodcutter cut down a tree if his saw tool has large teeth, only few teeth and that too at big distance?
It will be extremely difficult for him to penetrate the saw into the wood. He will go frustrated & go back his home empty hand.
We use the same principle and remove the blue portion from the light so it can’t penetrate into your eyes.
Blue is the harsh portion of the visible light spectrum
Let us tell you the meaning of blue light but do you know that you can not see the entire light because major portion of the light is not visible to the human eyes.
Consider the woodcutting (saw tool) below:
- Blue light is a part of visible portion of light. It is harsh, penetrative & intense. A physicist or physics teacher will tell you that blue light has short wavelength and high frequency.
- If you point light from Point-A to Point-B, the number of waves blue light will create in the way will be higher in number as compared to other colors. This phenomenon creates a lot of energy and makes the blue light penetrative.
- The reason why sky appears blue is because blue color scatters the most in the atmosphere. During the day time, the blue light is everywhere and people usually avoid looking at the sky.
- Natural blue light is important as it tell our brain that it is day time and we do not have to sleep. Artificial blue light could lead to biological issues in certain situations.
Artificial blue light may speed up blindness & interrupt sleep patterns
University of Toledo is a public research university in Ohio (USA). The 148 years old research center conducted a research on blue light. The study was lead by Assistant professor Dr. Ajith Karunarathne.
- Scientists found that blue light from digital screens & sun transforms important eye molecules into cell killers. Once these cells are dead they are dead forever. This may lead to vision loss.
- Other than vision loss, have you ever noticed that you find it difficult to sleep at night after working in front of digital screens ? Blue light may be responsible for the same.
- One should note that natural blue light is not that bad as it secretly tells our brain that it is day time and we have to stake awake. However when we expose our eyes in artificial blue light of mobile & laptop at night, many people find difficult to sleep.
Blue cut lenses are not meant for night driving - A disadvantage
When we are saying blue cut lenses, it simply means amber lenses and NOT clear lenses.
- Most of the people do not consider it a disadvantage or con as yellow blue cut lenses are mainly engineered to block or filter out the harsh portion of the blue light and not for night driving.
- However you may still wear these yellow lens blue cut glasses for day driving. Other than this if you live in country like Norway or Barrow(USA) where there is even Sun does not shine much then blue light blocking glasses are not advised as they may create psychological darkness.
- Broadly speaking blue cut lenses have almost zero side effect or disadvantage. Eye doctor should be contacted in case of any eye related problem. This is a standard advisory.
Blue cut glasses, Blue light filter glasses & Blue light blocking glasses are all same
- When this important optical technology was introduced, people started calling the lenses by various names. Blue light filter glasses or Blue light blocking glasses or Blue Cut Lenses have the same meaning.
- A point to be noted is that simple anti glare glasses are not blue light blocking lenses however blue light blocking lenses may have glare reduction properties.
Cheap price blue cut lenses could be costly for eyes
As a common practice, buyers desperately hunt for the cheapest pair of blue light blocking which brings undesired results.
Is it possible to buy a new iPhone for just Rs 10,000? It is not and if someone offers you the same, you will see such offer carefully. Right ? Same applies in optical industry also.
Here are some key points related to the price of blue cut lenses in India:
- Price of blue cut lenses or glasses depends on factors like refractive power of the lenses, optical standards maintained, lens coating and lens material used by the lens manufacturing company.
- A non branded pair of blue cut lenses can even cost you as low as Rs 1,000. Reputed brands can provide the same to for you for as high as Rs 5,000. There have been cases when the lens broke while the person was wearing the eyeglasses. One can imagine the consequences in such scenarios.
- Usually the price of good blue light blocking glasses of reputed brands in India starts from Rs 2,000.
Non colored blue cut lenses block just 20% blue light
A bicycle can not run faster than a motorbike. No matter which brand it is and no matter who is claiming what. Same is applicable with clear lenses that are said to block the blue light.
- It is a scientific fact that clear blue cut lenses can not block much blue light.
- Many retailers claim that their clear lenses block 100% blue light which is very difficult to accept.
- Such lenses can block hardly 20% blue light. They are mainly engineered to block the UV light. Although it does not mean that clear lenses are completely irrelevant.
- They may be appropriate for those who execute color sensitive work like photo editing, graphic designing etc or have less exposure to the blue light. Although Zebriana® which is an Indian brand of blue cut glasses has innovated premium lenses as well which are less yellowish and still provide high level of protection.
Never use a laser pen to test blue light blocking lenses
People often ask us that how to check blue cut lenses at home. Below are some important facts that you must understand.
- In India, it is seen that some optical retailers exhibit a laser test gimmick to their customers.
- The seller points laser beam on clear lens and then it appears that the lens has completely blocked the blue light as beam could not pass through the clear lens. Customer becomes confident and buys those clear blue light blocking glasses. So what went wrong ?
- Well, the secret of that trick is in the laser torch itself. It appeared that the laser beam was emitting blue light but in reality it was Violet and those lenses were also anti violet light and not anti blue light.
- There are good chances that those sellers might not be doing it purposely but they themselves don’t know the physics of the light and its properties.
- If you want to obtain maximum blue light protection then read the next point.
Amber lenses should be used to block the maximum blue light
- Out of all lenses available in optical industry, only amber lenses can effectively block the high energy visible (HEV) blue light.
- Study conducted at University of Toledo (USA) found that amber lenses are good at blocking the blue light and also improve sleep quality if worn few hours prior to sleep especially while working on mobile or laptop.
- Earlier this lens technology was being used in western countries only but Zebriana made it popular in India. These lenses appear softly yellowish and the wearer experience high level of reduced visual stress.
- They have the capability to block even 100% blue light but most of the good brands do not block that much due to the below mentioned reason.
Blue light blocking should be done in moderation
When we have fever, we take a pill of Paracetamol to reduce the fever & pain but since the pill works good that does not mean we should eat the entire leaflet of those pills. Right ?
- Due to lack of knowledge, people sometimes ask for blue light blocking glasses that can block or filter out 100% blue light.
- 100% blocking may be problematic as per biological perspective. Blue light tells our brain that it is day time and it has to keep the body awake but blocking it completely will create a psychological darkness or a virtual night for the brain. Brain will send wrong command to the body that it is a night time and as a result a person might feel sleepy throughout the day.
- An optimum blue light blocking percentage for a Mobile/ PC user could be around 65 to 85 %.
- 100% blue light blocking is suitable only to those who have severe insomnia or sleep disorder.