Short-sightedness, long-sightedness, presbyopia – there are many vision problems that can limit our visual perception. In most cases, an optimally fitted pair of glasses with the right lenses can help you see clearly once more. But what type of lens is suitable for what visual impairment? Lenses are the most important part of a pair of glasses, and the selection is nothing short of immense. BETTER VISION explains: What lenses are out there for effectively correcting defective vision, visual impairments and vision problems?
Single vision lenses are equally powerful across the entire lens surface, i.e. the prescription power is identical across the entire lens. They are used in distance and reading glasses – the two most common vision devices. What’s the difference? With reading glasses, single vision lenses are optimised for vision in the near zone and fitted to the long-sighted wearer’s standard reading distance. These lenses are great not only for books, but also for reading smaller fonts on a smartphone or tablet.
To better understand short- and long-sightedness we first need to explain how we see: in order to perceive things clearly, when we look at them our optical systems have to project them on the retina – and not in front of or behind it. This ability is compromised in people with a visual impairment. In long-sighted people, the eye visualises nearby objects behind the retina, which is why they see nearby objects as blurred. With short-sightedness, however, objects in the distance appear blurry because the short-sighted eye focuses images in front of the retina rather than on it. An optimally fitted pair of distance glasses can help you see nearby and faraway objects clearly once more.
Astigmatism can be corrected with single vision lenses. To achieve this, an additional prescription power is incorporated into the lens, which balances out the astigmatism: this is known as cylinder correction (“cyl” on the lens certificate). These are called toric lenses.
In patients with heterophoria, prism lenses optimise the interplay between the eyes. In the case of heterophoria, also known as hidden or latent strabismus, the wearer’s eyes are not exactly parallel, which impairs spatial vision. The brain and eye muscles are constantly trying to avoid double images, which can be very tiring for patients and often leads to headaches. Glasses with prisms balance out this irregular vision by virtue of a special polish used on at least one of the lenses. This improves mobility and the interplay between the eyes, which allows the wearer to see more clearly and in a more relaxed way.
Bifocal lenses consist of two lenses, which enable the wearer to see objects clearly both close up and at a distance. This is evident from the dividing line between the two lenses; the lower one is distinctly smaller and looks like a small window. This is the “reading zone” for near vision, and the rest of the lens ensures optimum vision at a distance. The dual prescription gives the lens its name: in Latin, bi means “two” and focal means “focal point.” In the past, bifocal lenses were commonly used to correct presbyopia. These days, they’re not the lens of choice. Many wearers find the clearly visible dividing line unappealing or even irritating, for instance when climbing stairs. What’s the solution? Modern progressive lenses. They offer a seamless transition between the vision zones and thus greater visual comfort.
Trifocal lenses (tri means “three”, focal means “focal point”) have a similar structure to bifocal lenses but are used by wearers with presbyopia. In addition to an optimisation for near and distance vision, another correction range has been integrated for intermediate distances, i.e. between 50 and 150 cm. Trifocal lenses have the same drawbacks as bifocal lenses: hard transitions between the vision zones and a visible divide between the lenses – both reasons why an increasing number of wearers opt for modern progressive lenses.
Progressive lenses have clear benefits compared to bifocal and trifocal lenses. Progressive lenses have a power for the near, intermediate and distance zones – and all of this in a lens with a seamless transition and no dividing line. The power is smooth from top to bottom and moves from distance to near vision. Progressive lenses enable clear, relaxed vision at all distances and are the perfect choice for correcting myopia, hyperopia and presbyopia. They’re great for reading, working at a computer or with your hands, or for simply gazing into the distance.
Thanks to state-of-the-art production methods with exceptional visual comfort, progressive lenses by ZEISS are precisely fitted to the wearer’s individual needs using a range of factors. Some relevant aspects are the interpupillary distance, the pantoscopic angle and the back vertex distance – to name but a few individual face parameters taken into account during production at ZEISS.
Blurred images in the transition zone or problems climbing stairs – one feature of earlier generations of progressive lenses – are by and large a thing of the past when it comes to progressive lenses. They enable not only clear, natural vision, but also fast focusing at all distances and in all directions. It’s an optimum pair of glasses for everyday use – no matter if this is your first pair, or if you want to switch from reading to progressive lenses, or have only needed distance lenses until now. Progressive lenses are also the ideal solution for people with normal vision who are beginning to develop presbyopia, or for people with astigmatism who are developing presbyopia.
Whatever your needs, your optician will be happy to help you find the right progressive lenses for you.
A pair of glasses needs to be as unique as the person wearing them. Depending on your lifestyle, hobbies or career, glasses need to be able to meet a whole range of different needs. That’s why it’s crucial to get a thorough visual needs analysis at the optician’s so they can recommend the right lenses for you. In addition to the “regular” lens options, there are also special kinds that help you achieve optimum vision. For example:
Using digital technologies such as smartphones and e-readers demands the utmost from our eyes every single day. Our eyes are having to become accustomed to a new range of near vision to accommodate the shorter distance at which we hold digital devices compared to a newspaper or a book. And they also require our eyes to constantly switch between different distances. This can lead to headaches and neck strain, and burning or tired eyes, particularly as we get older. One solution could be distance lenses with special support for your eyes at close range, like ZEISS Digital Lenses. They are sharply focused on the use of digital devices such as e-readers and smartphones and make it easier to focus in the near and distance ranges. ZEISS Digital Inside technology is also available for progressive lenses.
Being able to see well is a prerequisite for safe driving because on the road our eyes are working overtime: we constantly have to shift our focus between the street, the GPS, and the rear-view and wing mirrors. Unpleasant weather and adverse light conditions often make it difficult to see. Lenses specially optimised for particular situations faced while driving (e.g. ZEISS DriveSafe Lenses, available as single vision and progressive lenses) reduce the visual stress when driving, making it easier for drivers to see. For people who are sensitive to reflections, DriveSafe lenses can help combat perceived glare.
People usually notice the change when they’re 40 or older: working at a computer screen and shifting their gaze – i.e. from the keyboard to the monitor or from the calendar to the telephone – is suddenly more stressful for their eyes. In order to see clearly at different distances, they often unconsciously assume an uncomfortable posture, e.g. by leaning forward or raising their head. Back and neck pain, or dry or teary eyes, are just some of the possible consequences. ZEISS Office Lenses prevent this type of visual stress: they’re customised for your particular vision needs while at work and are optimised for all required distances while working at a computer screen. Reading and progressive lenses, however, are often not the ideal solution because the relevant areas of the lens are not optimised for office work. Reading glasses only enable optimum vision at a short distance – too short for working at the computer or looking at your desk. With progressive lenses, the wearer looks at the monitor through the intermediate area of the lens and must tilt their head upwards in order to see the screen clearly. Both types of lenses promote an unnatural posture while sitting, potentially causing muscle tension in your neck, shoulders and back, as well as headaches.
Whether you’re at work or at home, special sun lenses can step up your visual comfort in many situations. Did you know that all lenses can be made self-tinting? They offer perfect UV protection and optimum vision in one lens – thus eliminating the hassle of switching glasses. And these lenses come with everything you’d expect: improved contrast perception, less glare and an anti-reflective coating to top it all off. The lenses will tint depending on the intensity of the UV rays – from slightly tinted through to the intense shading you get from a pair of sunglasses. They darken in seconds and clear in just a few minutes.
There is a wide selection of lenses available, meaning you’re sure to find the right one for you. And what lenses are right for you? Find out in a quick and simple way by taking the My Vision Profile test now. Remember: a comprehensive analysis of your visual requirements is all you need to find the perfect lenses for you!