Here you will learn about polarized lenses the good and the bad.
What is polarized light
Polarized light occurs when scattered light reflects off any flat horizontal shiny surface. Such as water in a lake, a car windscreen, sand, snow, concrete and asphalt roads. Glare or polarized light does reduce visibility and it also distorts colour. As well it makes vision uncomfortable and painful. But it does not cause eye problems.
The white polarized glare shinning off the top of the water in this picture distorts the true colour. High quality polarized lenses would eliminate all of this glare. Alternatively low quality polarized lenses would eliminate as little as 30% of this glare.
Polarized lenses in theory should be better than plain lenses. But in reality this is not the case. Low quality polarized lenses do cause headaches. They also distort vision and lead to eye problems and blindness.
Polarized lenses and UV protection
Please note: Polarized lenses are not better or worse than plain lenses at eliminating harmful UV radiation. Just make sure you only buy sunglasses with *100% UV protection between 280Nm and 400Nm. *(Note the earth’s atmosphere absorbs all UVC from 100Nm to 280Nm). *Let me be clear, that means all UV rays between 280Nm to 400Nm. Not:- UV400, UVA, UVB, UVC or the USA and EU standard UV 280Nm to 380Nm.
Kids especially require total UV protection. This is due to the lack of chromophores within their eyes compared to adults. You can read more about UV protection here: Sunglasses the good and the bad
How they are made – Polarized Lenses the good and the bad
Low quality polarized lenses
Firstly the polarized film is made. Simply by heating and stretching a very soft PVA material. It then forms into long chain molecules. That subsequently align in one direction. Secondly by placing the polarized film between two thin sheets of either acrylic or TAC (acetate). It is then laminated together. Finally to create a curved lens. The flat laminated lens is then pressed into a mould.
These cheap, soft polarized lenses do scratch really easy. As well these thin lenses do distort the polarized film. Consequently many customers report that these lenses cause them headaches and eye fatigue. Also due to the distortion and low quality polarized sheet material used in these lenses they only cut as little as 30% of the reflected glare. Worse still the distortion from these lenses leads to major non-reversible eye damage. There after requiring prescription glasses to see.
Never buy cheap polarized lenses. Especially for children. Who are harder on sunglasses and will scratch these soft lenses. Scratched lenses do cause even more *stress to the eyes. Many of these cheap lenses also use a UV coating that children will scratch easily. Consequently leaving no UV protection.
*When you wear a scratched lens. The scratch appears as a blur in the image. And as the brain is not happy with the blur. It sends a small signal to the ciliary muscle (a small muscle that circles the lens of the eye) to adjust the lens for a clearer picture. Of course the blur remains. So the brain sends another signal to readjust. And this repeats until the scratched lens is removed. Just by wearing a scratched lens for one day the small ciliary muscle wears out. Then the only way to adjust vision is with prescription glasses.
How to know if it is a cheap polarized lens
- The material name, TAC (Tri-acetate cellulose).
- By pressing your finger tip on the centre of the outside surface of the lens. Cheap lenses will deflect under a little pressure. Any deflection will distort the polarized film.
- Tap the lens with you finger nail. A cheap lens gives a dead thud sound. A hard lenses will ring like glass when tapped.
High quality polarized lenses
High quality polarized lenses start with the same process. By heating and stretching a soft PVA material to form long chain molecules. But done very accurately with high quality material. Therefore these lenses will eliminate all polarized glare. This polarized film is then placed between two high quality lenses. Made from either polycarbonate, trivex, CR39 or glass.
Consequently by using these high quality lenses they do not require a UV coating that will scratch. Instead the lens has UV protection evenly distributed throughout. The finished lenses should be at least 2mm thick. This will then avoid any distortion of the polarized film. To avoid headaches and eye fatigue do not buy thinner lenses. They will only cause problems as reported by many customers. Of cause these high quality polarized lenses do cost more.
How to know if it is a high quality polarized lens
- The material name, polycarbonate, trivex, CR39 or glass.
- Press the centre of the outside surface of the lens with your finger tip. It should not deflect under pressure.
- Tap the lens with you finger nail. The sound of a hard lenses will ring like glass when tapped.
Important checks when buying polarized lenses
- Firstly to check that it is a polarized lens. You will need two pair of polarized sunglasses or two lenses to do this. Place the two sunglasses facing each other and horizontal. You should be able to see clearly through both lenses. Now while looking through one set of lenses facing each other slowly rotate one sunglasses lens until it is 90 degrees with the other lens. It should go from clear to dark and not transparent. If there is no change. Then either one or both of the lenses are not polarized.
- Secondly check the polarized lens is horizontal with the frame. Place the two sunglasses facing each other and horizontal. You should be able to see clearly through both lenses. If it is not perfectly clear. Then the installation of the lenses is incorrect. Now while looking through one set of lenses facing each other slowly rotate one sunglasses lens until it is 90 degrees with the other lens. If the lens goes completely dark before reaching 90 degrees. The lens has been incorrectly installed. In either one or both sunglasses. Don’t buy them as it will not filter the polarized light effectively. Then check the other lens the same way.
Our recommendation – Polarized Lenses the good and the bad
Eye sight is important. And low quality polarized sunglasses will damage eyesight. So never buy them. They also cost similar to high quality plain lenses sunglasses that will protect eyesight. So we recommend you buy the high quality plain sunglasses. If you can afford the high quality PC polarized sunglasses that will eliminate all reflective glare then buy these.
High quality adult PC polarized sunglasses can start at A$140.00 and go up to A$700.00 or higher depending on the brand. Our Idol Eyes Australia baby polarized sunglasses start at A$95.00 using the same high quality PC polarized lenses. Any prices lower than I have indicated will only be low quality polarized lenses and should be avoided if you care about your or your child’s eye health.
Myths about polarized lenses. – As seen on many websites by those with no experience in optics.
- Polarized lenses are made with a polarized coating. No, totally false.
- Polarized lenses have a special chemical applied to them to filter light. Totally wrong.
- Polarized coatings darkens the lens. Wrong.
- Polarized lenses aren’t available for regular reading glasses. Wrong.
- Darker lens colors provide higher levels of polarization. Wrong.
- Polarized lenses cut more UV radiation than plain lenses. No, not necessarily. Polarization has nothing to do with UV radiation. (Polarized lenses help eliminate polarized light or glare.)
- Polarized sunglasses are better than plain sunglasses. No, it firstly depends on the quality. But if both are high quality, the polarized lens will also eliminate that horrid glare. And if they are low quality polarized lenses you will end up with headaches, distorted vision all leading to eye problems and blindness.
- There are those who say that polarized lenses make them feel dizzy or disoriented. That is only caused by cheap distorted polarized lenses.
If you are looking for the very best baby or kids polarized sunglasses you certainly cannot buy better than our PC polarized range. Available in these terrific models: Baby Wrapz, Baby Wrapz 2 or Tiny tots II – IE88 and IE532. Check them out.
Don’t miss the latest sunglasses “WARNINGS” on this page. They will save your child’s eyesight.
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