Do you need High Index lenses?

When it comes to prescription glasses, a lot of consumers are still in the dark. There is a lot of terminology that is used in the Optometry practice to describe products and procedures, which often aren’t explained as thoroughly as they should be. A lot of this is around prescription lenses, and the options each customer has. In this post, I’m going to give you a little info on High Index lenses.

Firstly, what exactly are high index lenses? In extremely basic terms, they are prescription lenses made from a more compact material than the ‘standard’. Now, I could get extremely technical on this topic, but given a lot of my readers are from outside the industry, I’ll stick to the basics this time around! Lens materials are generally listed in the refractive index, 1.5 being the ‘standard’ across the industry. The higher the number equals a higher refractive index, and thinner and more compact the lens material. The most commonly used lens indices across Australia at the moment are: 1.5, 1.53, 1.6, 1.67 ad 1.74. There are more, but they have quite limited ranges of lens designs to choose from, and I don’t want to turn this into a novel;)

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The first reason your Optometrist or Optical Dispenser may recommend you consider high index lenses, is due to your prescription. When you have a prescription that requires a plus lens (+) the thickest part of the lens will be the centre. And when you require a minus lens (-), the outside edge will be the thickest part. The stronger (higher) the prescription, the thicker the lens will be. Let’s take a look at a few benefits of high index lenses for both plus and minus lens types.

img_1339Plus lenses

Plus lenses are thickest in the centre, which means you re more likely to see more edget thickness in a smaller frame. However, having the thickness in the centre means that once your prescription is close to or more than +2.00, the weight of your lenses can become an issue. On top of this, thickness in the centre of your lenses means there is more room within the lens for light to refract, which can cause aberrations resulting in vision that isn’t as ‘crisp’ as it could be for you. By looking at high index lens options you:

  • May reduce the weight of your lenses resulting in a more comfortable pair of glasses
  • Have less aberrations within the lens meaning a clearer result for your visual correction
  • Cosmetically your lenses will not look as ‘magnified’ to people looking at you, due to the more compact finish.
  • High index lenses are stronger than the standard material, so you will get better longevity from them too.

Minus lensesimg_1338

Minus lenses are thickest at the outside edge, and with high prescriptions, the lens can be sometimes seen to ‘overhang’ the frame. This is most noticeable with metal frames, but depending on the strength of your prescription, may also be noticed with acetate frames. As with high plus lenses, weight can be an issue, and having too much thickness on the outside of your prescription can cause a ‘swimming’ effect in your vision in the peripheral zones, especially when wearing progressive lens designs. Looking at high index lens options for you could:

  • Reduce the weight of your glasses resulting in more comfortable eyewear
  • Compact and reduce the amount of aberrations and ‘swim’ effect in your peripheral vision
  • Fit into your chosen frame better meaning you are less likely to have issues down the track
  • Cosmetically more appealing as the thickness won’t be as visible around the edge of your frame.
  • High index lenses are stronger than the standard material, so you will get better longevity from them too.

 

Below are some examples of when consumers should consider high index lenses, with any type or strength of prescription:

  • When you are looking to purchase eyewear with a higher than usual base curve, most commonly wrap sunglasses. The benefits in this case would be the more impact resistant properties of the lens material, as well as minimising any distortions to the side of the lens. When considering wrap sunglasses there are a lot of things to consider including lens design depending on your prescription, so always ensure you ask if your prescription is a good match for the frame you like.
  • When purchasing a semi-rimless frame. These are the frames that look to have frame at the top, but not the bottom. These designs actually have a piece of nylon attached to both sides of the lens area, which holds the lens in place. When your lenses are being made, a groove is bevelled into the centre of your lens where the nylon will sit in place. High index lenses are beneficial in this example again, for the strength – to help avoid chipping on those raw outside edges. Your Optical Dispenser should request a minimum edge thickness when you order this type too, also helping reduce the likelihood of lens chipping.
  • When purchasing a rimless frame design. Rimless frames are also referred to as 3 piece designs; two temples (arms) and the bridge (across the nose). These frames require the lenses to have holes drilled through them for the frame to then be fitted into place. You must have a high index lens material in this case as a 1.5 index will crack. On top of this, in a rimless design if your lenses are too heavy, the entire frame will always slip forward nomatter how well it is adjusted to your face. Balance and weight distribution is extremely important when considering a rimless frame design.
  • All children’s glasses! You guessed it: Mainly for the impact resistance, however there are obvious benefits for minimized weight (better fit) and thinner lenses (better clarity) as well.

So in summary, there is a reason every single consumer should at least consider high index lenses, but every single pair of glasses needs to be considered independently. Most reading glasses that stay at home with a prescription under +2.00 for example, wouldn’t need to be high index lenses unless the wearer is extremely sensitive to weight.

As always, have a more detailed discussion with your Optometrist or Optical dispenser on your specific needs, wants and expectations of your lenses. They will be able to inform you when it would be beneficial to go down this track, and give you examples of what to expect with the different outcomes for each material.

If you would like more detailed information on any of the above, please email or message me – I’m always happy to help! And as I mentioned earlier, this is a very basic summary of the topic….I could honesty write for days! But I hope this helps empower some of you to investigate a little further than you normally would. After all, when you have to wear them every day, your eyewear is one of the most important purchases you make.

Em x

Would you like fries with that?

Ah lens ‘extra’s’. Apparently we all need every single one of these lens ‘ad-ons’ no-matter what our prescription is, or what we use them for. Well, it’s time for me to myth-bust, and tell you that it’s simply not true. Unfortunately in our industry these days there is a culture (especially in the big groups and/or chain stores) to ‘upsell’. This absolutely infuriates me as we -as Eyecare specialists -should be here to help people with the best eye health solutions for them. There is no ‘standard’ or ‘one lens to suit all’;  consumers should always have a choice, and be educated on what their options are and why.

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Believe me, there are a lot of us out here still that take the time to go though each of these options with every single one of our customers, but it seems a lot of consumers are having trouble finding us. So, let me bring the information to you.

I’ve compiled a list below of the most common lens ‘extra’s’, so when you next go to purchase glasses you will at least have an idea of what you would like to pay for. You’ll be armed with enough information to ask the right questions if one is suggested for you, but not explained. I’ve also added a few general optical terms to help you understand the lingo as you go 😉 And remember, you ALWAYS have the right to ask questions, and leave if you are not happy with the information you’re given, or the discussion around what you are being invoiced for.

Most common Prescription Lens ‘Extra’s’.

Single Vision Grind lens: When your lens or prescription requires you to have your lenses made from scratch. This is most commonly required for high prescriptions, when you require prism, or to match a non-standard base curve for example, in wrap around sunglasses.

img_9474High Index material: Lenses can be made out of different materials for all kinds of reasons. Basically, the higher the index number, the more compact the material is. This results in lighter weight, clearer vision (less aberrations in the lens due to the more compact design) and a more impact resistant and strengthened finished product compared to a standard 1.5 lens material. The standard lens index is CR39, or 1.5. From there, you go up to (1.53, 1.54), 1.6, 1.67 and 1.74. The most common reasons to use a high index lens would be for a high prescription, better strength and impact resistance, premium clarity, a rimless or semi-rimless design or anyone who is weight sensitive on their nose.

Photochromic: Also known as ‘Transitions (brand name)’. Photochromic lenses are a material the lens is made from which, when activated by direct UV rays turns darker into a ‘tinted’ lens. The more direct UV on the lens, the darker it will go. While the activation of photochromic lenses has improved a lot over the last few years, they are not, and never will be instantaneous. They take longer to go back to clear than they do to go dark. Photochromic lenses have a very general life span of 18-24 months of full activation before they start to lose their ability to change, dependant on prescription, use and lens material.

img_5247Multicoat / Anti-Reflective coating: A clear coating that is infused into the top part of lenses designed to cut back glare and reflections. While not an actual colour, these coatings may have a very slight green or purple bloom to them in some lights. However, they are designed to make your lenses look invisible when worn, compared to the white light you see on people who don’t have the coating at all, which is extremely noticeable in photographs. This coating is also a super-tough hard coat and while nothing can ever make your lenses completely scratch proof, this does add an extra layer of protection from everyday marks and fine scratches. Years ago this coating was very hard to clean and came across as ‘smudgy’, but rest assured these days, the finishes are beautiful. I wouldn’t go without this on any of my specs.

Back surface Multicoat: Mainly recommended for sunglasses to stop reflections coming in from behind you onto the back of the lens (closest to your eye). This is useful on the water, or for anyone who is glare sensitive and uses their sunglasses for driving, prescription lenses or not.

img_9529Blue control coating: This is the newest technology for prescription eyewear and goes by a lot of different names. Basically, it is a coating similar to a multicoat (see above) but designed specifically to reduce blue light glare and reflections from technology. Aimed towards office workers, students and/ or gamers, this coating has a very slight yellow colour to it as the blue blocking technology blocks the colour from passing through the lens. By using this coating you will get less eye strain from computers and phones. This aides in a more ‘rested’ eye, and also is said to assist with a better sleeping pattern.

 

Polarised lenses: Polarised lenses are a premium form of sunglass lense designed to reduce glare. Not to be confused with ‘Polaroid’ (brand name), polarised lenses should be the go-to for almost anyone if possible. Traditionally, polarised lenses were available in three main colours; Grey, Brown and Green. Now, they come in a much wider colour palette, which includes graduated colours too (darker at the top, and graduates down to a lighter colour at the bottom of the lens). Both your basic tint sunglass lens and polarised lenses offer you high UV protection, but they are made very differently. Your base option – a ‘tint’ – starts as a clear lens and has a UV and colour tint wash added to theimg_7184 surface. This can fade over time, and only offers minimal (if any)reduction in glare. Polarised lenses however, have the polarising filter, UV, and colour all made within the lens itself, meaning better optics and no fading. Perfect for driving and all outdoor use, polarised lenses cut back glare from from roads, car windscreens, any shiny or bright surface and especially water. I’ll be doing much more on polarised lenses coming into summer.

 

This is a very short list, with basic info and by no means an ‘all-encompassing’ account of everything available. Before placing an order for new lenses, always make sure all of your options are discussed in detail with your Optometrist and / or Optical Dispenser. Each person and each pair of glasses is unique and requires individual considerations. And lastly, always – ALWAYS ask for an itemised quote before you place an order for lenses, so that you know exactly what is included. That way, nothing can be added to your order without your permission.

The Eyewear Girl xo

 

 

Trending: Mirror lenses

With the sunglass season heading our way FAST, it’s time we start taking a look at what will be trending this summer. And what better place to start than with a trend seen everywhere in Eyewear right now: Mirror lenses.

Also known as ‘flash’ or ‘iridium’, this is actually a reflective coating on the front surface of your lenses. You’ve all seen them; traditionally bright coloured lenses that act like a rainbow mirror, blocking your ability to see the wearers’ eyes. As with everything in eyewear, this trend is available in a lot of different qualities: the good, the bad and the ugly. From high end fashion labels to petrol stations and everything in between, there is no shortage of places to try this trend.

So why would I suggest avoiding the cheap versions at markets and heading to your Eyewear Specialty stores? Because there is a massive difference in quality of the coatings and spending any money at all on something that hasn’t been set properly on your lens is only going to end in tears.

Let’s take a quick look at what you should consider before investing in Mirror lenses:

PROS
– Very on trend this year
– It adds an extra level of glare-reduction to your lenses
– They are available in a very wide range of colours
– It means no one can see where you’re looking

– Available off the shelf and can also be ordered for prescription lenses

CONS
– Scratches and marks show up very easily. Once the coating is scratched it shows the dark lens base colour underneath
–  Once you get a scratch, sometimes the coating can begin to peel across the entire lens
–  People can’t see your eyes
–  They show signs of wear and tear quickly especially if exposed to heat ( eg left on a car dashboard)
–  They are REALLY HARD AND ANNOYING to photograph!!!!

As a brief summary, if you look after your glasses this trend is a great investment. They look good, are available in a wide range of colours to suit your personal taste and actually add to your eye protection. However, if you’re a little harder on your sunnies and prefer to not have to think about a case, or leaving them in the car, this might be one type of lens to skip. Small marks and scratches that you could normally get away with are much more noticeable with a mirror lens.

This year pastel colours are really making a splash, with pink, purple, soft gold and blue leading the way. Mirror lenses can be custom ordered at your independent Optometrists though, and most practices can offer you a wide range of lens and colour choices whether you have prescription or not. Your base lens can be whatever you want – a basic tint, polarised, photochromic, and in whatever colour you choose. And most lens manufacturers are offering not only the softer coloured mirror finishes, but also the traditional Yellow, Red, Orange, Green, Blue and Purple. Silver can be a little tricky, so always make sure you ask to see samples if you’re custom ordering. Silver Mirror coatings are so bright they’re almost white with some labs, while others are very light, and may even be called ‘black iridium’ rather than silver.

One question I get asked a lot about Mirror coatings is if they change the colour of your lens to look through. The general answer is no, as your base colour still holds the majority of your lens tint, however the mirror coating can have a light impact on your vision depending on both the colour of your base lens, as well as the colour of the mirror coating. For example, if you have a very soft brown base lens with a Red mirror coating, you may find that the lens may seem a little warmer to look through than it would without the mirror coating. However, if you had a solid grey (neutral) base tint with the same red mirror coating, you’re far less likely to notice a shift in the overall lens colour. As always, ask for samples and only purchase from a  store that you trust.

This is a trend I’m personally already on board with. 5 years ago would have been a different story, but I really like the way the softer pastel tones add another layer of style to the classic sunglass shapes without being too over the top. My best tip would be to try a few different colours on and make sure you pay attention to the lens you’re looking through, and not only what you’re looking at. After all, Sunglasses are, and will always be first and foremost about the health and  protection of your eyes.

The Eyewear Girl xo

 

 

Chroma Pop by Smith Optics

Let’s talk prescription sunglass lenses for a minute.

Luckily for me, my prescription has been mainly for computer use and reading but I’m starting to now find it beneficial for driving as well, so it seemed VERY appropriate for me to try a pair of prescription sunglasses.

And when I was told about the new ‘Chroma-pop’ prescription lens technology being released by Smith Optics, I thought that would be a great place to start!

So on top of having a frame that is lightweight, comfortable, and a classic style that is going to be timeless, the lenses were honestly even more impressive than I expected them to be.

Chroma pop technology not only creates a prescription lens that gives you extremely precise vision in a wrapped sunglass frame, but also focuses on individual colour enhancement so that your eyes can see brighter tones with less eye strain.

I’ve tested these lenses out when driving, walking, running in the rain , on the sand, lakes and ocean and all of these times I forgot I even had them on!

In summary, if you’re looking for an investment prescription pair of sunglasses, especially those of you who lead an active lifestyle, @smithoptics is definitely one brand to look into.

@smithoptics welcome to the prescription family!

Eyewear: Smith Cheetah Tort with Bronze polarised RX lenses

@smithoptics

M.

Lens types

Ok, so this is going to be obvious for some of you, but I know there are plenty of people out there that need to know this – I get asked every day!

Know what you’re buying class #1 is in session, it’s time to get the basics right.

What type of lenses am I wearing?

Single Vision: Exactly as it states, these lenses have one prescription across the entire lens. There are no distortions, visible sections or marks on the lens. img_2830Singe Vision lenses are most commonly made up as reading glasses (near), Distance, or intermediate (computer distance), however your Optometrist can make them up for you at basically any specific distance you need – just make sure you mention it to them at the time of your eye exam.

 

 

Bifocal: Bifocal lenses have 2 distinct sections in them, traditionally Distance and Near. Bifocals can also be used as Near and Intermediate, or Distance and Intermediate. With Bifocals there is a visible section at the bottom called the ‘Seg’ (Segment). This section is clear, but visible due to a different thicknesBifocals of lens on the bottom half, closer to the nasal side of the lens. The most common design of Bifocal is a ‘D-Seg’, because the Seg looks like a letter ‘D’ on its side. This Seg is available in different sizes, and you can also (with some prescriptions) get an ‘Executive Bifocal’ where the segment goes right the way across the lens.  These lenses are now not being used as often as in the past, as all of the technology advancements have moved forward in multifocals lens designs instead. Basically, Bifocals are old technology, and while still useful, we rarely see new glasses wearers opting for them.

 

Green Face a faceVocational lenses: Vocational lenses are the step between a single vision and a full multifocal (See below). They look like a single vision lens with no visible sections, but act more like a bifocal in that they offer 2 different sections. Unlike a bifocal, vocational lenses have a soft and smooth graduation between the sections, which is hardly noticeable. These are widely used for students and office workers, so that they can view near objects such as books or paperwork and still see computer screens (most commonly set at an intermediate distance) with one lens. 

 

Multifocal lenses (also knows as Progressive lenses): Multifocal lenses have three sections  – Near, Intermediate and Distance. They do have some distortions out in the peripheral sections on both sides of the lens, however large advancements have been made over the last few years to eliminate this and it is much better than it ever used to be. The lenses physically look like a single vision lens, with no noticeable sections to be seen. The pro’s of this type of lens is once you find the right design, you should be able to put them on in the  morning and do anything in them. The Eyewear Girl Face a Face hello 2The down side, is if you get motion sickness, or have someone dispense them incorrectly (happens WAY too often unfortunately) you may have issues adapting. But don’t let that dissuade you from trying them; there are non-adaption warranties with every lens manufacturer I have ever dealt with but of course, you will need to discuss this with your Optometrist before purchasing. Don’t give up, they’re worth adjusting to but also don’t keep quiet if you’re finding it difficult. There are plenty of options out there and your Optometrist can’t help if they don’t know there’s a problem.

 

So, that is a VERY basic run down of the main types of prescription lenses. On top of the above, each of these lens types come in different materials, with many coating options and most can be designed using many measurements of where your eye sits in the frame you have chosen and takes your unique prescription into account as well.

As mentioned earlier, this is your Know what you’re buying class #1, there will be plenty more with more info on everything, but please don’t hesitate to ask any questions below!

M.