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Blue Light, good or bad?

Idol Eyes Australia blog – All about sunglasses and eyes

 

The truth about blue light.

I am continually asked if the blue light emitted from all modern-day LED devices is harmful to our eyes. With so much *miss-information (*mainly from companies and people trying to sell you blue light blocking products or medicines) there is confusion about blue light and there is a lot of debate about this even among optometrists but what I am going to tell you is what is known about blue light.

What is blue light.

Blue light is classed as the wavelengths of light between 420–500nm (nano-meters). This is within the visible spectrum.

visible light spectrum
visible light spectrum

We know that there is 100 times more blue light from the sun than any consumer LED device. The blue light from the sun is extremely beneficial in setting our circadian rhythm or body clock which affects our sleep, blood pressure and heart rate, hormone secretion, and more. It also naturally suppresses the body’s melatonin production which does boost alertness and attention. Evidence is now associating circadian rhythms with eye growth and refractive error development. So it is imperative not to upset your natural body clock.

The trouble with blue light from LED devices.

Some researchers have shown that blue light at 445nm when the energy is 3 μW (micro-watts) or greater can cause cell damage. But this research was done under laboratory conditions, not on actual living tissue like an eye. And in a healthy human, all living tissue is constantly trying to repair itself.  Electronic devices typically emit no greater than 1 μW, and it has not been shown there is any harm or accumulative effect for such low energies.

So the real problem with LED devices is if they are used at night as the blue light can upset your circadian rhythm or body clock. We know for example night shift workers who do not get enough blue light of a day time to set their circadian rhythm correctly, do suffer from ill-health and a shorter life.

So what should you do about blue light.

If you don’t spend much time out doors of a day and are stuck in front of an electronic device then the small amount of blue light being emitted may actually help to set your circadian rhythm but of a night-time I would suggest that you turn off your devices. Yes, I said turn off your devices. And for all of you who just said, “What, are you crazy?” and cannot be without your device of a night then at least turn down the brightness of your display, push the device further away from your face and turn on a warm white light so the blue light from your device will not upset your natural body clock.

Conclusion on blue light.

Blue light does have real known benefits when received at the correct time, daylight hours. And preferable not received at night so you don’t upset your circadian rhythm.

I would not recommend wearing blue block sunglasses during day light hours (unless advised by an optometrist to do so) as you require the suns blue light to set your circadian rhythm, so that you will have a normal healthy life.

What I have stated is based on information we have today and this may change as we gain more information in the future.

The real dangers are from UV light.

Ultraviolet light is well-known to cause many eyes diseases and skin cancer, so protecting your eyes with good quality sunglasses is essential to prevent long-term exposure to UV light. We know that even small amounts of UV light over time do have an accumulative effect leading to eye diseases such as cataracts, pterygium, actinic & droplet keratites, pinguecula and macular degeneration.

Next installment – The real known danger of mobile devices to eyes.

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Frames and lens colour, what’s best and why?

Idol Eyes Australia blog – All about sunglasses and eyes

Frames, what’s best and why?

Frames are a vitally important part of sunglasses especially for babies and children. They don’t just need to look good they also have to handle the every day punishment that will come their way. They should not break easily. They have to be super comfortable or babies just will not wear them. They must give great UV protection. They should be light weight. This is just some of the criteria we think about each time we design a new sunglasses frame.

With more than 30 years experience making baby sunglasses and even longer making prescription eyewear we have tried all types of materials for the frames. Only a small number of materials pass our strict requirements allowing us to give our legendary 3-year guarantee. So the list is:

  1. Baby sunglasses – Rubber or rubber like materials. These are super comfortable and virtually unbreakable. With the aid of a headband the frame will contour to the shape of the face to eliminate UV rays from entering around the side of the frame.
  2. Toddler sunglasses – Rubber or impact resistant polycarbonate. Rubber has all the benefits mentioned above. Polycarbonate is 10 times more impact resistant than plastic, it is used in banks for its bullet proof qualities and is light-weight for comfort. Can be painted or printed making it a great material that lasts well.
  3. Kids sunglasses – Polycarbonate or optical quality steel. Polycarbonate has all the benefits mentioned above. Optical quality steel allows us to make adult metal styles like aviators or club-masters etc. for kids that will not bend out of shape or break easily.

Lenses, what’s best and why?

Without good quality lenses your just gambling with your child’s eyesight. The consequences are disastrous from terrible eye diseases like cataracts, pterygium, actinic & droplet keratitis, pinguecula and macular degeneration to blindness. Even buying sunglasses that are made to world standards can cause blindness. (See our earlier blog – The dangers of poorly made sunglasses).

Lens material.

We only use A-grade impact resistant polycarbonate. I do suggest that you read our Critical points to look for when buying baby – toddler sunglasses to find out why.

What is an A-grade lens? Firstly you have to understand how a lens is made. To make a good quality lens you firstly have to make a blank lens from “virgin” polycarbonate.

lens blanks
lens blanks

This blank lens allows all of the distortion during cooling, due to “shrinkage” to occur at the outer edge, which is then cut off when the blank is cut into the shape of the frame.

G-15 lens, cut into shape
G-15 lens, cut into shape

This first lens is classed as A-grade. The waste material which has been cut off is usually sent to a waste recycling plant. Due to the nature of polycarbonate (it does not recycle well) this waste is not used to make more lenses. But some companies in order to make a higher profit do recycle this waste material to make more lenses. This second made lens is classed as B-grade. I have heard that the waste material from this B-grade lens is recycled again to make C-grade and recycled again to make D-grade lenses. Recycling sounds great, right? The problem is polycarbonate is extremely impact resistant and the extra heating and cooling during the injection process makes the lens extremely brittle. All B-grade lenses will over a short period of time show signs of “crazing”, the term used to describe this. You can see this crazing in the lens in certain light, small web-like miniature cracks all over the lens. While C and D-grade lens can even show this “crazing” when new. The old saying, “You get what you pay for” is again true but not always, I have also seen really expensive sunglasses “craze” as well. Normally by brands that have no knowledge of how a pair of sunglasses are made, they try to buy the lowest price they possibly can, so they can make a large profit. Then they sell their really cheap product at a high price so the consumer will be mislead into believing the quality should be good. This crazing reflects shards of light into the eyes of the wearer making these sunglasses extremely uncomfortable and dangerous to wear.

Lens colour.

Another important aspect of lenses is the colour and also the darkness which will determine the amount of light that the lens will transmit. We know that 10% of all boys and 2% of girls are colour blind and if you buy sunglasses with the incorrect colour for these kids you compound the difficulties for them to distinguishing and learn colours. So unless your child has been tested for colour blindness or you simply want the best colour lens to reduce glare and not distort colour only one colour lens will achieve this. That colour is known as G-15. G, for neutral green and 15, for 15% light transmittance. Why do we only suggest neutral green? Simply this colour is in the middle of the visible light spectrum as seen in the in the colour chart below, which causes less distortion in all colours of the rainbow.

visible light spectrum
visible light spectrum

If you pick a lens in the lower end of the spectrum, say a blue or grey lens, these will distort colour in the higher end of the spectrum, red and yellow. And the exact same thing happens if you pick a lens in the higher end of the spectrum, say a red or yellow lens, these will distort colour in the lower end of the spectrum, blue or violet.

Lens category.

This refers to the darkness of the lens and an indication of what the sunglasses are intended to be used for. For all general purpose sunglasses we recommend category 3 or cat #3. Please see our earlier blog, The dangers of poorly made sunglasses. This does go into depth about lens category with a chart of the different categories and the intended use. It also points out the dangers of buying sunglasses with the incorrect category that are not made correctly.

 

If you have any questions or comments regarding any of our blogs or you need specific information please leave these in the,  “Leave a comment” and we will answer these as soon as possible.

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The dangers of poorly made sunglasses

 Idol Eyes Australia blog – All about sunglasses and eyes

 

Some of the dangers of poorly made sunglasses.

Many baby and children sunglasses brands being sold today are by well-meaning mums and dads that have no experience in optics. They normally fall in love with the cuteness of the product but without any optical knowledge make fatal mistakes in their designs and lens quality that can be detrimental to the health of your children’s eyes, leading to blindness. We will point out some of the dangers of poorly made sunglasses.

Please never buy “toy sunglasses”.

They don’t provide any UV light protection and the lenses material is soft and distorted, blurring the vision. They will also scratch easily causing the eye muscle (ciliary muscle) to constantly work to correct the distortion or scratch, which is impossible leading to the early wearing of prescription glasses.

Don’t buy non-labeled sunglasses.

You would think that with tough sunglasses standards in most countries that this would be enough to stop harmful sunglasses from entering the market. But we still see many well-known baby and children sunglasses brands being sold that don’t comply with the standards or are not tagged correctly with the compulsory standard number for your country. Simply don’t buy any sunglasses unless they are tagged or have the correct labeling with the sunglasses.

Even correctly labeled sunglasses can be dangerous.

  • Category # 4 lenses without side shields.

Even some sunglasses that are made to the European standard can cause major eye problems leading to blindness due to an error in the EN ISO 12312-1:2013+A1:2015 standard. In the EN standard, section 11.2 it specifies the Temporal Protective Requirements (side shields) for cat # 4 very dark special purpose sunglasses. All the sizes and positioning of the shields for adult’s sunglasses are given. But for some unknown reason the following was added for children’s sunglasses with cat # 4 lenses. “Note. Children benefit from sunglasses with temporal protection but in the absence of data, no dimensions are published in this edition of the standard.” This has been misinterpreted by some European brands to mean temporal or side shields are not required on children’s sunglasses with cat # 4 lenses and this is wrong. It should have said that “in the absence of data, scale the dimensions to suit” or the data should have been included so there would be no doubt that temporal protection is required on children’s sunglasses with cat # 4 lenses.

Many European brands promote the myth that the higher the category number or (CAT #) the better the quality. This is false. The category number or (CAT #) is only meant to indicate the intended use for the lens shade. The category numbers or (CAT #) are as follows in the chart:

Categories of lens filters
Categories of lens filters

As you can see from the chart, cat # 0 and 1 are not sunglasses and should never be purchased as sunglasses for your children as they have no sun-glare protection and limited UV protection. Even cat # 2 should be avoided as the lenses are still to light to give good sun-glare protection. Cat # 4 lenses are for special purpose only, recommended uses are skiing, mountaineering, etc. where there are excessive amounts of sun-glare that require very dark tinted lenses. These lenses only allow between 3 to 8 % of light to pass through the lens so if worn for normal everyday use your toddler will not be able to see clearly. These sunglasses also require side shields as the lenses are so dark the pupils dilate (open) and any gaps between the frame and the face allows more UV light to enter the open eye.

Dangerous CAT 4 lens with no side shields
Dangerous CAT 4 lens with no side shields

The above photo clearly shows a European brand with cat # 4 lenses and no side shields. Note that the temples or arms are very narrow so there is limited side protection from UV light entering a very wide-open pupil. This model is also designed to be worn upside down and this leaves a large gap above the bridge (nose) where UV light can enter a wide open eye. If your children have a pair of sunglasses with cat # 4 lenses and no side shields please stop using them, they will only cause major eye problems and lead to blindness. And don’t ever use them on the snow fields or your child will suffer from snow blindness.

Therefore, we only recommend you buy cat # 3 lenses for everyday use.

  • UV protection and the EN and USA standards.

Both the European Standard – EN ISO 12312-1:2013+A1:2015 and the USA Standard – ANSI Z80.3:2015 only classify UV light from 200nm up to 380nm not the real 400nm. This means they neglect UV light between 380nm – 400nm, this missing 20nm is 40% of the total UV light. So, when they claim 100% UV protection they mean 60% UV protection. Not good enough for babies or kids.

Some European and USA brands have seen this problem of the missing 20nm of UV light and then claim their lenses are UV400 or 100% UVA or 100% UVA and B. None of this type of labeling is mentioned in any standards and my concerns are:

  1. If the lenses are UV400 at what level of UV do these lenses start cutting UV light?
  2. If the lenses are 100% UVA what about UVB or UVC?
  3. If the lenses are 100% UVA and B what about UVC?

Remember babies require total UV protection as they have no chromophores in the eyes that protectively absorbs harmful UV rays.

Next installmentframes and lens colour, what’s best and why?

Girl wearing Idol Eyes Australia ski goggles

Blog

Idol Eyes Australia blog – All about sunglasses and eyes

This Idol Eyes Australia blog will be simple information to educate young mothers and those interested on the need to protect their children’s eyes.

With over 68 years experience in optics we know how important it is to protect the eyes from birth. Currently 1 in 7 adults over 50 years old in Australia have some form of blindness (other countries have similar statistics) and a high proportion of those are from UV light related eye diseases like cataracts, pterygium, actinic & droplet keratites, pinguecula and macular degeneration. All totally preventable and we will teach you how. So your children don’t end up as one of these terrible statistics.

Please take notice.

Have you ever noticed how much your baby hates the glare of the sun? Their eyes tightly closed, head turning from side to side, etc.

Think of it like this… you’re in bed for a couple of hours in the dark and someone wakes you and turns on the lights. Definitely bright and it takes a while to adjust your eyes.

Your baby has been in the dark for around 9 months (during pregnancy). Then you take them into the sun. It’s truly uncomfortable and extremely damaging to the eyes as babies have no chromophores (UV protective cells) that develop with age within the lens of their eyes like adults.

Chromophores, truly magic little cells.

We know that chromophores cells within the eyes have the ability to absorb harmful UV light. The problem is babies at birth don’t have these small protective cells. But they do grow quick and by the time most kids reach 5 years old they will have around 80% of the total number of these chromophores. The other 20% take some time to develop and most adult’s at 30 years of age will finally have the total amount.

Because babies and children lack these UV light protective cells we know that they receive 3 times more UV light than adults. And by 20 years of age they will have received 80% of their life time exposure. So it is vitally important to protect the eyes from birth to stop this accumulated exposure of harmful UV light.

Protection is easy.

It is easy and very inexpensive to protect baby’s eyes with good quality sunglasses from birth. But be aware not all sunglasses are created equal and some are down-right dangerous for babies and kids and can cause more harm than good.

Next installment – we will highlight some of the dangers of poorly made sunglasses.