The Guide to Progressive Lenses
If your optician has recommended a change, or if you feel that your current prescription is no longer suitably adjusting your vision, then it may be time to consider progressive lenses. If this is the case, then there are a number of questions you may have about what they are, how they work, and how best to choose the right ones for your needs.
What are progressive lenses?
A progressive lens is one that corrects multiple vision requirements in one lens. Therefore, one pair of glasses can be used for correcting your distance, intermediate, and nearsighted requirements. In real terms, this means the top of the lens is adapted for distance vision, and gradually diminishes in power towards the bottom, which is designed for reading or other “close up” tasks, like checking a price tag or using your smartphone.
In the past, progressive lenses were used to correct only two different eye prescriptions, and so were referred to as ‘bifocal lenses’. Bifocals were easy to spot because they had a line dividing the lens in two; with the upper half for distance vision, and the lower half for near vision. For many people, these were considered ugly and could even be less convenient than two separate pairs of glasses, as wearers would suffer from “image jump” when their focus flickered between the two halves of the lens.
Modern progressive lenses, however, eliminate this uncomfortable jump by having a smooth and consistent gradient between different lens powers. This is why they are also sometimes referred to as “multifocal” or “varifocal” lenses because they offer all of the advantages of the old bi- or trifocal lenses without the inconveniences and cosmetic drawbacks.
Do I need progressive glasses?
If you have multiple prescriptions for different distances, are juggling your life between two or three pairs of glasses, or are beginning to find that no single prescription is correcting your vision to a high enough standard for all daily activities, then progressive lenses could be the answer.
Most people start needing reading glasses after the age of 40. This is when the eye gradually loses its ability to focus on nearby objects, also known as presbyopia. Presbyopic patients greatly benefit from progressive lenses, compared to traditional bifocals and trifocals.
Advantages of progressive lenses
- With progressive lenses, you have clear vision at all viewing distances, giving you enhanced comfort. By having the seamless blend of prescription down the lens it can also ease headaches or disorientation that can come with more old fashioned bifocal lenses, where the lenses are divided into two. You don't have to change your posture to find perfect focus. This enables you to enjoy the sort of vision you had before presbyopia set in.
- Along with the above mentioned practical advantages, you also get the aesthetic benefit of no 'bifocal lines', hence a more youthful look.
- Wearers of bifocal lenses who work on computers regularly have to sit close to the screen, tilt their head back and bring their chin ahead to see through the lower part of their lenses. This makes for an unnatural posture, which if maintained for prolonged periods lead to muscle strain, neck and shoulder pain, and ultimately computer vision syndrome(CVS). If you spend a lot of time in front of screens wearing progressive lenses for computer use will enhance your daily comfort, further eliminating the risk of CVS.
- With progressive lenses, you can look ahead to comfortably see distant objects, view your computer through the intermediate zone by looking just slightly downward and read up close comfortably by lowering your gaze a little more.
- Additionally, by having all your vision correction needs met in one set of lenses, your day to day life will become easier, as you are not constantly having to carry around two or three different pairs of glasses.
Disadvantages of progressive lenses
In terms of disadvantages, it is a well-known fact that progressive lenses do take some getting used to. It is quite common that progressive lenses make you dizzy while adjusting to them. The first few weeks it can be disorientating to do things that require an accurate sense of depth perception like climbing the stairs. Adjusting to the changes in lens power can produce a ‘swim’ effect, where the wearer feels like their field of vision is constantly moving. After a few weeks, however, this will usually subside.
Bifocal vs Progressive Glasses
- Progressive lenses are the modern multifocal glasses gaining popularity over bifocals worldwide. Bifocals correct the same problems but use older technology to do so.
- Progressive lenses have a seamless, invisible design, where the prescription progressively changes throughout the lens. Bifocals have a visible and harsh line.
- Progressive glasses have multiple powers built into the lens, so you can see far away at the top of the lens and gradually see closer when you look more down. In comparison, bifocals only have two powers.
- Progressive glasses look better, have a smoother transition, and are overall more practical in daily usage than bifocals.
Even though progressive lenses can be a little more expensive than bifocals, the price is worth-while, because they have more benefits than bifocals, as listed above. They look better, are more practical, provide more optical powers, and are easier to use
Adapting to Progressives
As previously stated, adapting to progressive lenses can take some time; ranging from several hours to several days. This is because the gradient power of the lens can cause aberrations in your peripheral vision. The left and right extremes of the lens are not as strongly “progressive” as the central, vertical corridor, meaning your vision could seem blurry when looking to the sides. However, as with any developing technology, each new generation of progressive lenses represents an improvement on the last, and many people never suffer any problems at all.
The latest generation of progressive lenses is known as “free-form” lenses, which are made with a computer-aided manufacturing process to reduce aberrations. Each lens is customized exactly to the position of the wearer’s eye, taking into account the angles between each eye and the surface of the lens when looking in different directions, providing the sharpest, crispest image possible, as well as enhanced peripheral vision.
How to choose your progressive lenses
Depending on your vision needs, there are a variety of progressive lenses available to you. There are lenses designed specifically in accordance with whether you have a greater need for distance, intermediate, or near vision correction.
Broadly speaking, there are four types of progressive lenses:
Standard progressive lenses
With these lenses, you will have a large portion of the lens given to the near-vision part of your prescription. However, they are less adaptable when it comes to choosing your preferred glasses frames as they require a certain amount of lens space in order to achieve a smoother transition between distance and near vision prescriptions.
Short Corridor Progressive Lenses
These lenses were designed to fit into small, more fashionable glasses frames. The corridor refers to the space given to your nearsighted prescription. It can be fairly narrow, so they take some time to adapt to. You should keep this in mind if you know you need to read or use your smartphone often and therefore require progressive lenses reading glasses.
Computer Progressive Lenses
Designed specifically for tasks that use your intermediate vision prescription, these lenses give a lot of space to the intermediate area of your prescription. They are often used by those who work with computers on a daily basis.
Premium Progressive Lenses
Premium progressive lenses are usually totally customized to the wearer's needs and so are compatible with any frame shape or size. They also provide a much larger near vision area.
For all detailed optical and lens queries it is always recommended you ask your optician. They will be able to advise you on what lenses are best for you and to answer any queries you may have that pertain to your specific optical needs.