Spectacle lenses – your questions answered
- It’s the first time I’ve needed glasses. What do I need to know about choosing lenses?
When you talk to the dispensing optician about your spectacles, they will explain to you about the different lenses that you can choose. Most people opt for plastic lenses today: they are lighter and safer. Plastic is softer than glass and can scratch more easily so you will be offered an anti-scratch coating. More and more people are opting for an anti-reflection coating. This allows more light to pass through the lens, with the dual benefits of letting you see more clearly, and allowing people to see your eyes clearly too.
- I need glasses to help me read. What are my choices?
If you need glasses to help you read, you can opt for glasses that just focus your sight on close work. You may prefer bifocals or varifocals, where a portion of the lens is suitable for distance vision too. People who wear glasses for distance work all the time, and get to the age where they need a different prescription for reading often choose bifocal or varifocal lenses. These allow you to swap from distance to close work without changing spectacles. Like all new specs, they can take time to get used to. Some people prefer to have a different pair of glasses for distance and for close work. This can work well if you are unsteady on your feet, or if you do one task for a long period of time and don’t need to swap your glasses often.
- What is a bifocal lens?
A bifocal lens has a clear division between the top part, for distance vision, and the smaller segment in the bottom half of the lens that helps you focus on reading material. The reading segment can come in different shapes, some with a curved top and some with a flat top.
Your dispensing optician can show you the different designs and help you decide if one is right for you.
- What is a varifocal lens?
Varifocal (or ‘progressive’) lenses allow you to see clearly in the distance, then the focus of the lens changes gradually as you lower your gaze, giving you a portion of the lens for intermediate work and the lowest part for focussing on reading material. You can’t see the transition when you look at the lens, unlike bifocal lenses where there is a clear line. Some people choose varifocals because they feel they look less aging, while others like them because of the increased flexibility compared to bifocals. They are handier than having a pair of specs for distance vision and one for close up.
Varifocals come in different designs. Some have a narrow central channel, which is ideal if you mainly look at things in the distance or close up. Others have a wider central portion which might be suitable if you do a lot of work at a middle distance, such as on a work bench or computer. Everyone’s needs will vary, so discuss your lifestyle with your dispensing optician and they will help choose the best lens for you.
- Should I choose glass or plastic spectacle lenses?
Today, most people choose plastics lenses. They are lighter than glass lenses, and weigh less on your face. Glass lenses are a little thinner than a plastic lens of the same prescription. Plastic is more break resistant, so is significantly safer, provides more protection and cannot splinter. Plastic is softer and more likely to scratch, but the chance of scratches can be reduced with an anti-scratch coating. Plastic lenses are easier to tint in a range of colours too.
- I’ve got a high prescription. What lenses will be best for me?
If you are very short sighted, you may have noticed that your lenses have thick edges and appear to make your eyes smaller. Your spectacles may feel heavy and mark the bridge of your nose. Opticians can offer you lenses that are thinner at the edge and lighter too. These lenses are known as high index lenses, and bend light more efficiently than standard lenses. There are different high index lenses: some are only a little thinner than standard plastic lenses, while others are thinner still. Generally the thinnest and lightest lenses cost the most. High index lenses generally come with an anti-reflection coating as standard, as this improves the appearance of the lenses
If you are very long sighted, as well as benefitting from high index lens materials, your optician may suggest an aspheric design. Your lenses are likely to be thickest in the centre, which can magnify the appearance of your eyes. An aspheric design cuts down the central thickness, reducing the weight and magnification.
- How do I protect my eyes at work?
If you work outdoors you may need to protect your eyes from hazards like grit and dust as well as from regular exposure to UV light. Whether you are a gardener, traffic warden, police or road worker, specialist lens options, such as photochromic lenses, can help working outdoors more comfortable.
When photochromic lenses are exposed to ultraviolet rays they darken and provide visual comfort in direct sunlight. The depth of tint will vary depending on the extent of the light and the outside temperature. The depth of tint fades when moving out of the direct sunlight returning to a pale tint indoors or to almost clear at night. You can work wearing photochromic lenses without changing spectacles, a big benefit. Some photochromic lenses are available in Trivex and polycarbonate material if you also need impact protection.
If you work in a more hazardous setting there are laws to ensure that your employer takes safety seriously. Depending on your role, you may be required to wear protective eyewear, either all the time or when on the factory floor. Safety eyewear can be prescription or non-prescription and come in a variety of options including spectacles, goggles and shields.
Safety spectacles have side shields attached to the side of the frames to avoid any foreign objects entering the eye and surrounding area and it is likely that the lenses supplied will be plastic (thickened CR39), toughened glass (thermally or chemically), low energy impact materials, or materials such as Polycarbonate or Trivex.
Ask your registered dispensing optician for advice on the right eye protection for you.
- How do I protect my eyes at home?
In everyday life, a good pair of spectacle lenses won’t just help you see better. They will protect your eyes too. Talk to your dispensing optician about lens coatings which resist smudges, dust, scratches, glare and repel water. You should also think about protecting your eyes against UV light on a daily basis.
- How do I protect my eyes on holiday?
If you are off to sunnier climes, have you thought about protection from UV light? Don’t just slap on the sunscreen: also remember to pack a pair of sunglasses. It’s not advised to put sunscreen on or near your eyes and lids, so your sunspecs are the only protection that your eyes have. Sunglasses need to fit your face well in order to be effective at stopping UV light, so make sure that you get advice when choosing. Always look for the CE mark when buying lenses. Speak to a registered dispensing optician for advice on prescription sunglasses and fitting.
- What are the best lenses for daytime driving?
There are different lenses and filters that can improve your driving experience. Polarised lenses will help reduce glare reflected a wet road. Tints aren’t recommended for night driving, but some people find a yellow tint is good for enhanced contrast during the daytime. Brown or grey tints don’t affect your colour perception which makes then a good choice. If you pick lenses with the darkest part of the tint at the top and less intensity at the bottom it is easier to see the instrument panel inside the car. Read more about driving and your eyes. Talk to the registered dispensing optician in your local optical practice as they are trained and educated in the latest products and technology to help you improve your driving experience.
- My eyes get tired when driving, what should I do?
Have you had a recent eye test? The first thing to do is to check that your specs are up to date and your eyes are healthy. Then talk to a dispensing optician about the different types of lenses available. There are some lenses that are specifically designed for driving. If you usually wear varifocals and do a lot of driving, there are varifocals specifically designed for this purpose. Read more about driving and your eyes. Talk to the registered dispensing optician in your local optical practice as they are trained and educated in the latest products and technology to help you improve your driving experience.
- I struggle with glare from oncoming headlights when driving at night, what tints or filters might help?
When wearing spectacles for driving, it is recommended that you ask for an anti-reflection coating to reduce the effects of glare. This is the best solution for driving at night, and is recommended rather than using a tint. Ask your registered dispensing optician for further advice. Read more about driving and your eyes. Talk to the registered dispensing optician in your local optical practice as they are trained and educated in the latest products and technology to help you improve your driving experience.
- What are the best type of lenses for high levels of short-sightedness?
If you are very short-sighted, your spectacle lenses can feel thick and heavy and make your eyes appear smaller. High index materials have been developed which allow your lenses to be thinner and lighter. Ask the dispensing optician to talk to you about better lens materials and designs.
- What are the best sort of lenses for high levels of long-sightedness?
If you are very long-sighted, your spectacle lenses can feel thick and heavy and magnify your eyes. Aspheric lens designs can thin and flatten the lens, reducing the magnifying effect. High index materials have been developed which allow your lenses to be thinner and lighter. Ask the dispensing optician to talk to you about better lens materials and designs.
- I work on a computer and my eyes get tired. What can you advise?
Did you know there are spectacle lenses designed specifically for computer work? Book an appointment for an eye test to check your vision and eye health. If you need glasses, the dispensing optician can talk to you about these newer lenses that are specially designed for working at a desk, and make it easier to switch between a computer and paperwork. They can complement your existing spectacles and lenses. Office-style lenses often come with coatings that will enhance contrast and cut reflections. Ask your registered dispensing optician for advice on lenses for the office.
- My eyes are sensitive to sunlight, what lenses might help?
If you suffer from dazzle, glare or sore eyes when out and about there are various types of lenses that can help you. Ask your optician about polarised lenses. These can cut glare from light reflecting off a wet road, for example. Photochromic lenses darken automatically as the sun comes out which can also help people with sensitive eyes. There are a range of tints too: ask your optician to show you different colours and depths of tint so you can see which might help you most. Don’t forget to ask about protection from both UVA and UVB light to reduce long term risks to your eyes.
- I have an eye problem that makes my eyes sensitive to light, what might help?
Eye conditions such as cataract can make you more sensitive to light. This can cause discomfort and reduce your vision in bright conditions. Talk to your optician, because there are specific frames and lenses that can help. Frames with chunky rims and sides can cut the amount of light reaching your eyes at an angle and causing glare. The optician can help you find a frame that fits well. You can also find tinted specs that fit over your regular glasses. Tints in different colours and depths can also help without affecting your vision. Ask to look through different tints to see what works for you. Different tints may work well for you in different situations, depending on the weather or if you are indoors or outdoors. Don’t forget to ask about protection from both UVA and UVB light.
- Will tinted spectacles help my migraines?
Some people who experience migraines are also sensitive to light. If this sounds like you, talk to your local optician about tinted spectacle lenses. There is a wide range of colour and depth of tint available now, and it is worth trying different tints to see which you find most helpful. Some people find certain colours cause migraines, while others reduce the problems. Some opticians have taken additional training and/or have specific equipment in their practices to help assess which coloured lenses can help with conditions such as migraines.
- What is a lenticular lens and who might it help?
Some people with very high spectacle prescriptions benefit from lenticular lenses. The part of the lens that helps you to see better is in the centre, within a wider border of clear lens, giving a shape like a fried egg. This cuts the central thickness of the lens and ensures the specs are lighter.
- What is a slab-off bifocal and who might it help?
A slab-off lens can help if you have a difference between your two eyes, and also need different powers of spectacle lens for distance and near vision. This can lead to an imbalance between the two eyes when you try to read. The slab-off technique can be applied to bifocal and varifocal lenses. By altering the angle at which one lens is ground you can avoid the lenses inducing double vision.
- What is a Franklin split lens and who might it help?
Franklin split lenses are special bifocals which provide a very wide zone for near vision. They are produced by cementing together two lens halves, one the distance portion and one the near portion. They can help people who have a difference between their two eyes to avoid vertical jump or imbalance.
- What are freeform lenses?
Freeform lenses use computer-aided design and surfacing to create high-level, customised spectacle lenses with your unique prescription. They can help to reduce glare and halo effects caused by light sources at night, such as car headlights.
- How are freeform lenses made?
To create freeform lenses, once you have chosen a frame, the registered dispensing optician will fit the frame to your face. They will then scan your eyes using specialised equipment that measures your face and eye position. They will also measure how the frame sits in front of your eyes, how it wraps around your face, and even how you tilt your head. The software combines your physical data with your spectacle prescription in order to provide the best vision, day and night. The optician will send your order direct to an optical lab. Your lenses will be created on a computer-driven, free-form generator. This machine is able to work to extremely high levels of accuracy and can generate more complex surface shapes than traditional glazing equipment. The lenses are then fitted to your frame. Finally, the registered dispensing optician will readjust the frame for the best fit on your face.
- Why should I choose freeform lenses?
Freeform lenses use an advanced manufacturing technique which reduces aberrations in spectacle lenses. You may not notice spectacle lens aberrations, or if you have a high prescription and high index lenses you may have noticed a coloured tint to the periphery of what you can see when you are looking away from the centre of your lens. Advances in lens manufacturing mean that lenses can be made without these aberrations. If you want sharper vision, or suffer from glare and problems with night vision, talk to a registered dispensing optician about freeform lenses.
- Who will benefit from freeform lenses?
Anyone can benefit from freeform lenses, but you will find most benefit if you have a high prescription, if you are bothered by glare or your vision seems indistinct. Make sure that you have had a recent eye examination, then talk to a registered dispensing optician about freeform lenses.
- What lenses are best for children’s specs?
Children should always have plastic lenses in their glasses. You can ask for polycarbonate or Trivex lenses which are lighter, thinner and tougher than regular plastic lenses. They also offer 100 percent protection from harmful UV light. An antireflection coating on the lenses can give your child clearer vision. You can get prescription sunglasses for children, or you can opt for photochromic lenses which darken on exposure to sunlight so your child doesn’t need to think about swapping from one pair of specs to another.
- Glare resistant coatings
If you struggle with dazzle and glare, ask your optician about ‘anti-reflection’ coatings. Ultra- thin layers on the lens surfaces eliminate reflections and dramatically reduce glare. A lens with an anti-reflection or ‘AR’ coating also gives better vision for night driving, working under fluorescent light, and for computer use. Another benefit is that your eyes will no longer be hidden by your specs! If you look carefully you can see this microscopically thin coating as a hint of blue/green at certain angles, but looking straight on it renders your lenses super-clear. Almost every pair of specs comes with an AR coating nowadays, and it is an essential if you have high index lenses for a high prescription. Ask your registered dispensing optician for advice on whether this coating will suit you.
- Scratch-resistant coatings
Do your specs get scratched? A scratch-resistant coating creates a much tougher surface on lenses. No coating can totally protect your specs, but this technology gives glasses a longer life and ensures your lenses stay clear. Almost every pair of specs comes with a scratch resistant coating nowadays. Ask your registered dispensing optician for advice on whether this will suit you.
- Water resistant coatings
Do you struggle with your specs in the rain or in a steamy kitchen? New water-resistant treatments repels water droplets, keeping your vision as clear as possible. The water rolls into small droplets and slides off the lens with ease. Ask your registered dispensing optician to advise on if this coating will suit you.
- UV Protection
A clear filter on the lenses will protect your eyes from damaging UV light. This is a great option for all glasses, not just sunglasses. UV light has been linked to the development of cataracts and eye cancer. If you regularly spend time outdoors you should opt for UV protection on your everyday specs. Ask your registered dispensing optician for advice whether if this coating will suit you.