Aspheric lenses have come as a huge relief to high prescription patients who had to earlier make do with spherical lenses that magnify the eyes and are unattractive. Aspheric lenses are a superior alternative
What is an aspheric lens? Is it a kind of lens? How is it different from polycarbonate or Trivex? These twoare lens materials and undoubtedly the best in the business. But aspheric is a lens design. So what is so special about this design? Well, to begin with, let’s understand the difference between spherical and aspherical lenses. A spherical lens is when the lens is thickest at the centre and gradually thins as it fans out till the end. This is the most used design in all corrective lenses. The problem is, when the correction is for farsightedness the lens is really thick at the centre. This makes the eyeglass look a trifle ‘bulgy’ at the centre and thereby, a mite unattractive. With aspheric lenses, this issue of ‘bulginess’ is rectified. How? Simple, aspheric lenses have a more complex front surface that gradually changes in curvature from the centre of the lens to the edge. This ensures that the ‘centre thickness’ does not exist. Aspheric glasses mean fat is out, thin is in.
Lenses Of Aspheric
Aspheric lenses are best made with high-index materials. The combination is potent, resulting in slimmer and lighter lenses. The difference between aspheric and conventional lenses is most noticeable in ‘plus’ lenses. Aspheric lenses can also be made for ‘minus’ lenses. The thickness of a ‘minus’ lens is maximum at the edges and reduces towards the centre. When aspheric lenses are used for ‘minus’ lenses, the difference is less visibly dramatic.
The Aspheric Advantage
It is quite remarkable how aspheric lenses have changed the game in the optical business. Optical professionals across the world have taken to aspheric lenses. There are some distinct advantages in using aspheric lenses, even though they are more expensive than conventional lenses. Let’s list and preview these advantages:
- Aspheric lenses reduce the magnification of the eyes. Far-sighted people often look a bit nerdy because of the way their eyes seem to boggle due to the thick eyeglasses made from conventional lenses. But since the aspheric lens is slimmer and flatter, the eyes are not magnified and look normal even though they are wearing such high-powered lenses. They also fit closer to the face, thanks to their flatter curves. Children are especially sensitive about their appearance. Aspheric lenses can prove to be particularly useful for them.
- Incidentally, the reverse is true for those with nearsightedness. Regular eyeglasses made from conventional lenses make eyes look smaller than normal, which is equally unattractive. But with aspheric glasses, the look is as close to normal as possible.
- Regular lenses cause a minor visual disturbance when the eye is moved from the centre to the left or right, or even below. As the eye moves from the centre of the lens there is a certain distortion. But aspheric lenses reduce this ‘distortion’ and give a better and wider and clearer vision.
- Aspheric lenses are lighter. So they are ideal for the elderly who are not comfortable with wearing heavy lenses.
- Most contact lens wearers overwear their contacts as they want to avoid wearing thick, unattractive spectacle lenses. Aspheric lenses are a great option for them, helping prevent overuse of their contacts.
Things To Remember
While the advantages of aspheric lenses are aplenty, there are a few key things to remember before recommending aspheric lenses to patients.
- Aspheric lenses are best for farsightedness and high degrees of nearsightedness, but they also come in good stead for other eye ailments like astigmatism, anisometropia, and presbyopia too. So, patients suffering from these eye conditions can be recommended aspheric lenses.
- A critical step in the dispensing of aspheric glasses is the selection of the correct frame. It’s not always about high fashion, especially in the case of aspheric lenses. As the lenses are a bit complicatedly made, it is important that the frame is of the correct size. Here, it is important that eye care professionals help patients choose the correct frame while explaining its importance to them.
- Aspheric lenses are flatter. That’s why they are more attractive, right? The fall-out of this is that the eyeglass will be closer to the patient’s face than the one made with conventional lens. This may cause reflection both in the inner and outer surface of the lens, which can cause problems ranging from annoyance to distractions to image blocking. Ensure to put an anti-reflection coating on the lenses.
Dispensing Rules For Aspherics
Perfection is everything when it comes to aspherics. A well-designed aspheric lens can result in excellent optical and cosmetic results. But aspherics are not as forgiving of dispensing errors as spherical lenses. If an aspheric lens is fit incorrectly, the lens may end up being optically worse than a conventional lens would have been. That’s why dispensing rules become more crucial for aspherics.
- Since the aspheric lens measurements are a little difficult, it requires an elevated level of skill and dexterity.
- Correct measurements require time. So do not hurry up the process. The customer is paying a high price for aspheric lenses and will be both disappointed and critical if the end result is not good enough. So take your time while scripting the measurements.
- As stated earlier, frame selection is important. It is best to recommend a frame that is not overly large. The frame should allow the eyes to be as centred as possible in it. Doing so will reduce asymmetry in the curvature of the front of the lens.
- Always apply an anti-reflective coating on the lens to reduce the reflections.
Product-wise
There are many companies in the market that make aspheric lenses. But, for some people, precision that is generated through expertise and experience can be found only amongst the top gear lens companies, such as Essilor, Zeiss and Nikon. Let’s examine what these companies have on offer.
Essilor’s Airwear
Essilor’s emphasis on clarity of vision, eye health care, safety and comfort ensures that the spectacle lenses it offers are impact resistant, lighter and thinner. Essilor’s special range of aspheric design is called the Airwear series. With a tagline that says, ‘lighter, safer and greener’, it explains the company’s commitment to long-lasting good eyewear. With the focus being on lightness and strength that are combined together to make the final product, Essilor brings to the table a special range of aspheric spectacle lenses. With a refractive index of 1.59 along with the aspheric design, Essilor states that the Airwear series is 30 per cent lighter and 25 per cent thinner than other lower index lenses. All spectacle lenses in minus power that are over 2D, have a centre thickness of 1.3 mm. Airwear spectacle lenses score in a few other areas as well. According to the company, it absorbs 100 per cent of the harmful UV rays. It also comes with a tough hard coat called ‘Titus’ that absorbs shocks, making this one of the most preferred scratch-resistant options in the range. This strength of Airwear spectacle lenses makes it best suited for any activity or occasion, from driving to high-activity ridden daily chores.
ZEISS Single Vision AS
The ZEISS Single Vision AS is an aspheric design crafted on a plastic base. It is rotationally symmetrical, has a flatter front and has superior visual quality. It is much thinner and flatter than the ZEISS Single Vision spheric lens. It is in fact 20 per cent thinner and lighter. The ZEISS Single Vision AS offers greater visual comfort and is aesthetically fine-tuned as well. There are two distinct advantages in wearing this lens. As the material used is plastic, it is an ideal option for children needing to wear corrective glasses. It is also ideal for sports professionals who would benefit largely because of its unbreakable quality.
ZEISS was Europe’s first manufacturer of plastic lens to have successfully polymerised a plastic lens with the super-high index 1.665 for batch production. Since the polymerisation is done in-house, it is possible for ZEISS to provide such a quality product. The range is available in 1.74, 1.67, 1.6 and 1.5.
Nikon Lite AS
Nikon is an expert in aspheric design. In fact, the unique aspheric design for eyeglasses is said to be borrowed from Nikon camera lenses and is considered as one of Nikon’s most outstanding achievements. Nikon recommends Nikon Lite AS for low to middle prescription wearers. The range is available in 1.5,1.56, 1.6, 1.67 and 1.74. All the Nikon Single Vision Lenses feature Nikon’s Advanced Aspheric Design. The bottom line promise is that the lens will not just be thinner, lighter and flatter and offer sharp, clear vision, it will look good and have limited peripheral distortion.
Aspheric lenses have been a major breakthrough in the optical industry offering patients with high prescription, eyewear that is lightweight, distortion free, thinner and that offers more cosmetic value.
With inputs from:
Onkar Pirdankar,
Assistant Professor & Consultant Optometrist,
Lotus College of Optometry
TagsEssilor Zeiss
FAQs
What is a disadvantage of aspheric lenses? ›
There are a few downsides to aspherical lenses. The main issue is their cost since they take more effort to manufacture. These lenses may also require reflective coatings that traditional lenses do not, and they require accurate measurements of your pupillary distance.
Why are aspheric lenses thinner? ›Simple, aspheric lenses have a more complex front surface that gradually changes in curvature from the centre of the lens to the edge. This ensures that the 'centre thickness' does not exist. Aspheric glasses mean fat is out, thin is in. Aspheric lenses are best made with high-index materials.
What is thin aspheric? ›Aspheric lenses are slimmer, flatter optical lenses compared to traditional prescription lenses. These lenses are available in both glasses and contacts, making more stylish options available to prescription lens wearers than ever.
When should I use aspheric lenses? ›You might want to choose aspheric lenses when you have a strong prescription or you experience dramatic refractive errors. Dramatic refractive errors mean you have significant problems with the way light focuses on your retina, which means you'll need stronger corrective measures.
What are the advantages of an aspheric lens? ›An aspheric lens has varying curvature across the surface of the lens rather than a uniformly spherical shape. Aspheric contacts can correct spherical aberration and reduce the blurring of vision. They can provide sharper, clearer, and brighter vision in some people.
What would be a good reason for using aspheric lens design? ›Because aspheric lenses have flatter curves than conventional lenses, they fit closer to your face. This is a major benefit for anyone wearing a strong correction.
What are the pros and cons of aspheric lenses? ›Aspheric lenses offer many advantages, such as the correction of spherical aberrations and improved image quality, but also have some disadvantages, including a complex design and manufacturing process, fragility, and limited availability.
Are aspheric lenses better for astigmatism? ›The aspheric lens design can help to increase visual acuity even in poor lighting conditions, or when driving in the dark, when working with a computer, or for sports activities that require fast focus. Aspheric lenses can correct low astigmatism up to –0.75, or presbyopia.
What is the difference between aspheric and spheric lenses? ›What is the difference between aspheric and spheric lenses? Aspherical spectacle lenses use varying curves across their surface to reduce bulk and make them flatter in their profile. Spherical lenses use a singular curve in their profile, making them simpler but bulkier, especially in the centre of the lens.
What are Costco eyeglass lenses made of? ›Customers can choose from different lens materials, including polycarbonate, high-index, and Trivex lenses. When it comes to eyeglass lenses, Costco offers a wide range of options for their customers. Customers can choose from different lens materials, including polycarbonate, high-index, and Trivex lenses.
Are all progressive lenses aspheric? ›
Every progressive lens utilizes aspheric curves to constantly change power as the wearer's eye travels from distance to near.
Are aspheric lenses better cataract surgery? ›Aspheric IOLs are monofocal lenses that correct for spherical aberration. The result is a lens that will provide better overall vision than traditional IOLs, especially at night. Patients who choose an aspheric IOL can expect: Improved contrast sensitivity.
What is the purpose of aspheric lenses? ›Aspheric eyeglass lenses allow for crisper vision than standard "best form" lenses, mostly when looking in other directions than the lens optical center. Moreover, the reduction of the magnification effect of a lens may help with prescriptions that have different powers in the 2 eyes (anisometropia).
Do thinner lenses make your eyes look smaller? ›Large and thick frames make your eyes appear smaller as the distance to the eye increases, so going for smaller, thinner glasses will help minimise this effect. Request thinner lenses: Optical technology has come a long way, covering ground on lens reduction methods for those with high prescription powers.
What are the characteristics of aspheric lenses? ›Aspherical Lenses. Aspherical lenses are optical lenses that feature a non-spherical but rotationally symmetric radius of curvature. Unlike spherical lenses, they have a radius of curvature that varies from the center to the edge of the lens. The variation from sphericity is often much too small to detect with the eye.
What prescription type do aspheric lenses benefit most? ›An aspheric lens is designed with less curvature than its traditional counterpart. Think: flatter and thinner. In both farsighted and nearsighted prescriptions, aspheric lenses provide a slimmer profile and minimize eye distortion without compromising optical quality.
What is the difference between 1.67 and 1.74 lenses? ›What's the Difference Between 1.67 and 1.74 High-Index Lenses? 1.74 high-index lenses are up to 10% thinner than 1.67 high-index lenses.
What is a best form lens? ›Best form lenses are positive lenses with minimized spherical aberrations. They are used if the highest demands are made of the spot image. The spherical aberration is clearly defined by the diameter of the incident beam and its wavelength.
Do aspheric lenses reduce magnification? ›Aspheric lenses offer less magnification for plus power wearers and less minification for minus power wearers. They are also thinner and lighter in weight than standard spherical lenses. In plus lenses, the surface becomes flatter away from the center.
Which lens is the lightest corrective lens material in common use? ›Trivex is the lightest material available and meets high-velocity impact standards. A scratch-resistant coating is required for this lens.
What lenses don t magnify eyes? ›
Aspheric Lenses
For those with higher prescriptions an aspheric lens design can help prevent unwanted magnification. Aspheric lenses are typically High Index lenses that are made with much flatter curves. This slimmer design reduces magnification and improves comfort and vision.
To make high index lenses even more attractive, most of them have an “aspheric” design. This means that, instead of having a round (or “spherical”) curve on the front surface, these lenses have a curve that gradually changes from the center of the lens to the periphery.
What is astigmatism in your eye? ›Astigmatism is a common eye problem that can make your vision blurry or distorted. It happens when your cornea (the clear front layer of your eye) or lens (an inner part of your eye that helps the eye focus) has a different shape than normal. The only way to find out if you have astigmatism is to get an eye exam.
What type of lens is best for astigmatism? ›For mild or moderate astigmatism, polycarbonate lenses are a great option. But if your astigmatism is more severe (say, greater than +/-4.0 diopters), high-index lenses will give you the vision correction you need while maintaining a thin profile. An anti-reflective coating is a must for glasses for astigmatism.
Which lenses are the best choice for people with astigmatism? ›Toric contact lenses are often the best choice for contact lens wearers with an astigmatism, because they're specifically designed to address the problem. The special shape of a toric lens creates different refractive, or focusing, powers that can help correct either a corneal or a lenticular astigmatism.
What is the best lens for cataract surgery with astigmatism? ›If you're comfortable wearing glasses after cataract surgery, a monofocal lens may be the right choice. If you want to avoid wearing distance glasses after cataract surgery and have astigmatism, a toric lens might be appropriate.
What are aspheric lens surfaces most commonly used with? ›Due to their low cost and good performance, molded aspheres are commonly used in inexpensive consumer cameras, camera phones, and CD players. They are also commonly used for laser diode collimation, and for coupling light into and out of optical fibers.
Who makes aspheric lenses? ›The CooperVision® portfolio of monthly, bi-weekly, and daily lenses are designed with aspheric optics. The Aberration Neutralizing System™ utilizes aspheric optics to neutralize the aberrations from the eye in the Biofinity®, Avaira Vitality™ and MyDay® families.
Is LensCrafters better than Costco? ›Generally, Costco Optical will offer you a better price than LensCrafters when you buy glasses or contact lenses. However, depending on what your vision insurance plan covers, you may be less satisfied overall with the quality of the product.
Who makes Kirkland Signature lenses? ›Kirkland Signature Premium Daily Disposable (Same as MyDay Daily Disposable) are Store Brands contact lenses. They are made of Silicone Hydrogel and are manufactured by CooperVision.
What brand of progressive lenses does Costco use? ›
Kirkland Signature™ HD Progressive Lenses:
Custom made lens for your prescription and selection. Offers a larger reading area and less distortion than standard lenses. Quality and value.
Besides progressives and bifocals, there are also trifocal lenses or bifocal contacts. Like progressives, trifocals offer three fields of vision, but have two visible segment lines that mean a double image jump. New designs in bifocal contact lenses are also an alternative.
What are the two types of progressive lenses? ›There are two types of progressive lenses, standard and premium. While one is as the name implies standard, the other is really your best option. That's because premium progressive lenses are customized to your eyes and offer a wider viewing area than standard ones.
What is the difference between aspheric and monofocal lenses? ›An Aspheric implant lens is a type of monofocal (focuses only one distance) implant that is specifically designed to reduce the visual disturbances caused by the optical aberrations found in ordinary lens implants.
What is the cost of aspheric IOL lens? ›Aspheric IOLs INTRAOCULAR LENS at Rs 6750/unit in Mumbai | ID: 22916089291.
What are the three types of cataract lenses? ›There are three different types of intraocular lenses available including monofocal, toric, and presbyopic-correcting.
What is the focal length of aspheric lenses? ›These lenses each have a focal length of 4.6 mm, resulting in an approximate major beam diameter of 2.5 mm.
Are thin and light lenses worth it? ›These thinnest eyeglass lenses can help in vision correction as they are made with light and thin materials but are strong and can provide increased comfort. The thin lenses glasses reduce the chances of eye distortion, due to which your eyes and whole face can be seen clearly.
What is the thinnest lens for high prescriptions? ›What are the Thinnest Lenses for High Prescription Glasses? 1.74 index lenses are the thinnest lenses for high prescriptions available. These ultra-light, ultra-sleek lenses are the thinnest kind developed yet, and accommodate the highest prescriptions possible.
Is it worth paying for thinner lenses? ›If you're moderately, or very short-sighted you'll benefit from thinner lenses as the edge thickness of your lenses will be more visible. Lenses with a refractive index of 1.6 are ideal for prescriptions where the – value of your SPH prescription is between -2.50 and -4.00.
Are aspheric lenses better? ›
You might feel self-conscious about your glasses and how they make you look, but aspheric lenses can help. With a flatter curve, there's less central thickness and less eye magnification. They also correct distortion and create a higher-quality image. Aspheric lenses can also improve your peripheral vision.
What is the difference between single and double aspheric lenses? ›Double aspheric lenses provide an even larger field of view with minimum distortion towards the edges. Due to the double aspheric lenses benefits, they cost a little bit more than single aspheric lenses but are thinner and more lightweight. If you want low cost glasses with thin and comfortable lenses, come to us.
What are the disadvantages of wearing lens? ›- Red Eye. Having red eyes can happen for all sorts of reasons. ...
- Dry Eye. Contacts have a tendency to dry out your eyes, which can cause negative symptoms. ...
- Infection. ...
- Corneal Vascularization. ...
- Eye Ulcers. ...
- Conjunctivitis.
Lenses are prone to shifting, dryness, and other complications. Eyes are more susceptible to infection with contact lens wear. There is a higher risk of bacterial infections with contact lens users. Infections can be caused by prolonged wear, build-up, bacteria, neglectful care and sleeping with contacts on.
What are the problems of spherical lenses? ›Now, the problem is that the light that hits the edges of a spherical lens gets refracted at a different angle compared to the light that hits the center. As a result, those rays will converge in a different, non-optimal focal point. You can recognize spherical aberration when your photos get blurry towards the edges.
Who should not wear lenses? ›Not everyone who needs glasses wants to wear contacts, but nine out of 10 people who want to wear them can wear contacts. However, contact lenses may not be a good option for people who: Have had repeated eye infections. Suffer from severe allergic reactions.
Which lenses are best for eyes? ›Which Lens Is Best For Eyes: High Index. Although high-index lenses are lighter and thinner than polycarbonate lenses, they are nevertheless effective for most prescriptions. In your hunt for the best eyeglass lenses, keep in mind that high-index lenses are also a cost-effective alternative for families.
Is it better to wear lenses or glasses? ›Contacts sit comfortably on the eye's curvature, giving you excellent focus and a wider field of view than glasses. Your lenses won't be affected by adverse weather conditions such as fog and rain, while they also won't steam up in hotter conditions.
What are the advantages of not so thick lenses? ›(v)-(c) Not-so-thick lenses would not make the telescope very heavy and they will also allow a considerable amount of light to pass through them.
Which cataract lens is best for night driving? ›The TECNIS® Multifocal IOL is one premium IOL that's improved the lives of many patients. This FDA-approved IOL can boost your vision in all light conditions, making it a fantastic choice for low-light conditions to allow significantly better eyesight while driving at night.
What is the most popular cataract lens? ›
Monofocal. The most common type of lens used with cataract surgery is a monofocal IOL.
Can I wear spherical lenses with astigmatism? ›Lens types
Soft spherical lenses—the most common type of contact lens—do not correct for astigmatism because they focus light equally from all directions. However, those with mild astigmatism can wear this type of soft contact lens.
Spherical lenses are some of the most common lenses used, in part because they project images onto the sensor without affecting their aspect ratios. Other types of lenses — like anamorphic lenses — will project a compressed version of an image, which usually requires stretching in post-production to display properly.
Is astigmatism corrected using a spherical lens? ›Astigmatic errors are corrected with the use of sphero-cylindrical spectacle lenses or toric contact lenses. The term 'toric' indicates varying degrees of curvature along the meridians of a curved surface. Before spectacle dispensing, the power and axis of a cylinder are refined during subjective refraction.