Welcome to the OpticianWorks Consumers Guide To Buying Glasses 2018
I am a licensed optician who has worked for a mall-based optical chain and two different independent doctors of optometry, both with large retail sales. I have more than twenty-five years “in the business.” I know exactly what optical products cost and how they are marked up. You are not going to read any “industry insider information” here, because none exists. What I can share with you are some common-sense guidelines.
I am NOT selling anything!
I do NOT recommend any particular brand name products.
I do NOT accept advertising money from optical companies.
About That Eyeglass “Prescription”
As a consumer, the first thing you must know is that you own your eyeglass “prescription.” Once your exam has been paid for, you may ask for a copy of it. By law, your doctor must give it to you. You are free to take that “prescription” anywhere you want to have your glasses made. Your doctor has no right to hesitate or refuse to provide you with your prescription.
§456.2 Separation of examination and dispensing. It is an unfair act or practice for an ophthalmologist or optometrist to:
(a) Fail to provide to the patient one copy of the patient’s prescription immediately after the eye examination is completed. Provided: An ophthalmologist or optometrist may refuse to give the patient a copy of the patient’s prescription until the patient has paid for the eye examination, but only if that ophthalmologist or optometrist would have required immediate payment from that patient had the examination revealed that no ophthalmic goods were required;
(b) Condition the availability of an eye examination to any person on a requirement that the patient agree to purchase any ophthalmic goods from the ophthalmologist or optometrist;
(c) Charge the patient any fee in addition to the ophthalmologist’s or optometrist’s examination fee as a condition to releasing the prescription to the patient. Provided: An ophthalmologist or optometrist may charge an additional fee for verifying ophthalmic goods dispensed by another seller when the additional fee is imposed at the time the verification is performed; or
(d) Place on the prescription, or require the patient to sign, or deliver to the patient a form or notice waiving or disclaiming the liability or responsibility of the ophthalmologist or optometrist for the accuracy of the eye examination or the accuracy of the ophthalmic goods and services dispensed by another seller.
The use of the word “prescription” is misleading and it implies that the form you are being handed has medical value. It does not.
Currently your routine eye exam consists of two parts.
Part of the exam is medically based and includes a thorough physical examination of the entire eye and visual system. This is often done with the eye dilated and it is when the doctor looks inside the eye with their bio-microscope. The medical portion of the exam can prevent blindness and detect a wide range of other serious health related issues. Medical based eye exams are an important part of your overall healthcare plan. Medical eye exams are a objective screening tool.
The other part, refraction is the determination of your eyeglass “prescription.” It is when you are looking at the eye chart and answering the, “which is better, one or two” questions. Refraction is a subjective, non-medical test, which in many countries can be performed by eye care providers who are not doctors. Computer assisted instruments and online apps that provide self guided refraction are becoming available.
Prescriptions written for eyeglasses (not contacts) may, or may not, have an expiration date. This varies by the doctor, state law and the individual practice. It is up to you to balance the healthcare of your eyes and annual eye exams with the cost savings of using a dated prescription.
Glasses with routine “prescriptions” are NOT medical devices. They are two pieces of curved plastic held in place with a couple of bent wires. Contact lenses, since they are in direct contact with the eye, are a medical device.
(About Shopping Online Is Below – And I’m Not Against It!)
Know that almost all lenses are made at huge factories called wholesale optical labs, not behind the wall in your local optical shop. The fanciest and most expensive store in town may well be using the same exact optical lab as the discount place on the corner. Lenses may be ground to fit a frame in a shop, but rarely ground to fill an individual prescription. Like lenses, most frames are made by the millions, in huge factories located all over the globe. They are rarely hand-crafted in the back room at the shop.
Why is the optical shop important? Because your shopping experience should be fun and satisfying and you should feel great about your purchase. Shopping for your new eyeglasses is no different than shopping for a new car or a new pair of shoes. You will determine what is within your budget and what you want your shopping experience to be.
Optical shops provide you with hundreds of frame choices to try on so you can determine what looks and fits best. Maintaining that inventory costs the business $10,000 to $100,000.
Shops stock repair parts and have the tools to properly and safely adjust and repair your eyewear. They also offer education and information about new products that can provide you with better vision.
Only an experienced eye care professional can provide you with a proper fit for your new eyewear. Only an experienced optician or eye care professional can take accurate measurements for the proper alignment of your eyeglass lenses. Your eye care professional will take the time and care to assure you are getting the proper prescription by doing a final inspection of the product.
Unlike online retailers, your local shop can often handle warranty issues and broken glasses on the spot.
Consumers Guide To Buying Glasses About Frames:
Frame pricing is consistent throughout the industry. Almost all optical retailers mark up frames along similar guidelines. It is common to find identical frames selling for within a few dollars of each other in local markets. Unless the frame is unique to a very small vendor, chances are excellent that at least one other shop in town is selling the same frame. A little price comparison is always a good idea.
We all want to look good!
Eyewear today is fashion-driven!
So, rule number one is: You will pay more for a frame with a designer name. Frame manufacturers spend millions of dollars buying the rights to put designer names on their frame lines. They have to recoup that cost somewhere, so the higher the brand recognition is, the higher the cost will be. Stores will also charge a premium for exclusive brands, styles and the latest fashion trends in eyewear.
That leads us to rule number two: Designer frames look better than non-designer frames. Do not kid yourself. The frame companies know how to manipulate style. The best-looking shapes, styles and colors are combined in the higher cost designer lines.
Now on to rule number three: Just because a frame has a designer name does not mean it is a better product. In fact, it was most likely made on the very same assembly line and from the very same materials as the company’s house brand.
When you buy a frame, think about how and when you will wear it. If you wear your contact lenses 99% of the time, then buy a house-brand frame, and save your money. Does it really matter what your bedside readers look like? Do you need a designer frame for your computer glasses?
To see how a frame should fit and how a frame should NOT fit see the Consumers Guide To Buying Glasses Frame Fit Photo Gallery
Consumers Guide To Buying Glasses About Lenses:
Unlike frames, lens pricing is very inconsistent throughout the industry. Almost all optical retailers will mark up lenses to what the local market will bear. Of course, there are exceptions, and it is up to you to shop around and be sure you are not overpaying for a specific lens.
Single vision lenses are pretty basic stuff. If you have a low prescription, or wear your contact lenses most of the time, then just about any lens will do. If you have a higher prescription and wear your glasses all the time, then you will want to consider aspheric designs, non-glare coatings, and high-index materials (see below).
Lined multi-focal lenses (lined bi-focals and lined tri-focals the lenses with the “half-moon”) really have not changed much in the last twenty years. You will probably get what you had before and be pretty happy with them. Obviously I could wear any lens I want. I actually prefer a lined bi-focal over a progressive.
Not all progressive lenses are created equal.
To some degree you really do get what you pay for. Is $400.00 a heck of a lot of money for some pieces of plastic? Yes it is. But, that is the way it is…
Beware of buying the progressive lens that, “just came out”. Advertising is a powerful medium, and lens companies spend millions of dollars promoting new lenses. As a consumer, you only see the tip of the iceberg, since many of the ads appear in trade magazines which are directed at doctors and Eye Care Professionals. In addition to the ads, there is a legion of industry representatives out there selling the lenses directly to the stores. Sometimes, lens manufacturers have to push sales on lenses that don’t necessarily perform well.
Beware The Smoke & Mirror Products:
Beware of glasses with switches, wires, knobs, batteries and any “new-technology” that has not been on the market for a few years and had the bugs worked out.
Don’t say I didn’t warn you!
What to Know When Buying Eyeglasses:
Do know that all current, brand-name, lenses and many new free-form house brands are pretty darn good – to – excellent. If you are being told that a certain lens is somehow above and beyond all others and is worth considerably more money than other lenses, you are probably being fed worthless sales propaganda.
Do buy a quality non-glare coating. Non-glare coatings allow you to see better, look better, and make for a better pair of glasses. Get the best non-glare coating you can afford. If you can afford it, get the good coating on every pair you have. Just like lenses, your optician should be able to tell you what brand and what type of non-glare coating you are getting and give you information about your coating. If you must choose between a cheap non-glare coating or none at all choose none at all. Cheap AR or non-glare coatings do nothing but scratch, smudge and smear.
Do ask about which lens you are getting. If your optician cannot tell you then you are probably being sold a very low-end product. Today the lenses being sold may not be a “brand name” but may still be of extremely high quality. Listen for terms like “house” or “independent” free-form.
Do try to buy a lens produced in the last year or two. Progressive lenses are still getting improvements, so many new designs are actually easier to wear than those made just a few years ago.
Do know that in the US your doctor determines your prescription, not your optician. So please do not get angry with them when a new prescription does not work for you. It would be (a little) like yelling at your pharmacist because your antibiotic did not cure your cold.
Do realize that if you are presbyopic (meaning that you need an add power, and should wear a lined multi-focal or progressive) and that if you have a change in prescription, that one area of your vision will be better and one will be worse!
PLEASE Re-Read that — Realize that if you are presbyopic (meaning that you need an add power, and wear a multi-focal or progressive) and that if you have a change in prescription that one area of your vision will be better and one will be worse! Stop torturing your doctor, optician or ECP! It is a simple fact that you cannot have perfect vision in all ranges. You are o-l-d. Get over it. If the doctor’s prescription provides you with crisp distance vision, chances are that you will lose some of the clarity that you had with near vision in your old pair. The only way around this is having individual pairs of glasses for the different ranges you need.
Pssst- Here is one little insider secret that I will let you in on: Bifocal contact lenses rarely, if ever, work! Or, they work for a year or so and as your reading power increases with age they stop working. Don’t say I didn’t warn you!
Do buy a BIG frame if you want a progressive to work well. If you want a progressive to work well, it needs room to do it. Yes, the optician will probably tell you it will work just fine, and the lens company will probably tell you it will work, but guess what? It won’t.
Do NOT buy the latest new thing, unless it comes with a 100% money back guarantee.
Is a pair of $500 glasses better than a pair of $200 glasses? Not necessarily.
Expect to pay about this much for a complete pair of glasses (frame AND lenses):
Single vision glasses: Between $100 and $300.
Lined multi-focal glasses: Between $150 and $400.
Progressive glasses: Between $200 and $600.
AR or non-glare coatings: add $75 to $150.
Changeable tint lenses: add $75 to $150.
What you need to know about taking your glasses back to the shop:
Know that a frame that has been returned can often be reused or returned to the manufacturer for a credit. Lenses, since they are ground especially for your individual pair of glasses and prescription cannot be reused and become trash. For that reason you must understand the reluctance of your doctor or optician to remake lenses without being 100% sure that they know e-x-a-c-t-l-y what the reason is.
For that reason you will need to explain to them what is not right about your prescription and/or glasses, not just throw them down and say, “These don’t work.” See: Why Can’t I See Out of My New Glasses below.
Online Eyeglass Shopping
You cannot overlook a complete pair of glasses for $18.00 when similar or even identical products are selling for a hundred dollars more at the local shop. Online eyewear sales are a routine part of the business.
It is possible to purchase a pair of perfectly good glasses online. Heck, I would say that your chances of getting a great pair of glasses from a large online retailer are actually better than what you might get through several of the managed care plan companies offered through your doctor’s office!
With that said, if you have a low prescription, you are looking for an inexpensive pair of glasses and you prefer to shop online then I would suggest going with one of the larger online retailers, Warby Parker and Zenni Optical seem to be the leaders.
Just like shoes or clothing you purchase online, for goodness sake, if your online glasses don’t fit, don’t work, give you a headache, well, then DON”T WEAR THEM – SEND THEM BACK!
PLEASE! If you are wearing progressive lenses and/or have a high prescription go and see a professional. DO NOT SHOP ONLINE for progressives or high prescriptions! The fit and measurements for progressives and higher prescriptions need to be made by a human.
Consumers Guide To Buying Glasses Optical FAQ
You may also want to visit our YouTube Channel: Laramy-K On YouTube
Here is a list I am compiling of some frequently asked questions you are likely to have when you go to your doctor’s office or optical shop.
Q: How can I tell if my optician is reputable and competent?
A: You can’t. You can judge the likelihood of it by how long they have been in business and that they appear to be confident, competent and knowledgeable. “Certification”, since it varies greatly from state-to-state, is not a very good indicator of competence.
Q: Can you remove scratches from a lens?
A: NO! NO! NO! Your eyeglass Rx is created by the curves on the front and back of the lens. If you “buffed” out the scratch you would change the curve and you would change the Rx and/or create a big blurry spot. There is no “magic” liquid that can fill a scratch. Trust me if there was we would have it on hand for when we slip and scratch a new lens!
Q: What should I bring with me when I go in for an eye exam?
A: #1 Your eyecare insurance information. Know it before you go in! If you don’t know what it is then contact your company HR department and find out. Also bring a current pair of glasses, the box for both your R and L contact lenses if you wear them and a copy of your last written Rx if you have it.
Psst… Insider tip #2: If you wear glasses then bring them with you to your exam. Don’t think that “starting from scratch” will change anything. The only thing that will happen is that you will seriously tick off the doctor! The very person that is trying to help you.
Q: What makes a high prescription?
A: Most opticians will consider a prescription “high” when it is over +3.00 or over -5.00. The higher the power of a lens the more important the frame fit and measurements taken are.
Q: Why can’t I use my eyeglass prescription for contact lenses?
A: Because a contact lens sits directly on your cornea. Every cornea has unique curves that must be matched to the lens for proper fit. Because the lens sits on the eye the power of a contact lens is often different than that for eyeglasses. Wearing a contact lens that is not fit properly can cause damage to the cornea. Unlike glasses contact lenses are a MEDICAL device and are not something to play with.
Q: When should I consider “high-index”?
A: When your prescription is “high” and/or your cylinder value (the middle number in your Rx) is over 2.00.
Q: Why doesn’t the reading area of a progressive lens go all the way across the bottom?
A: Eyeglass prescription are created by the curvature of the lens. You cannot overcome physics. The industry has thousands of doctoral level optical engineers working 24/7 on making the best lens possible, trust me if it could be done it would be done. Just like with most things in life anything that does everything rarely does all of them well.
Q: What is this free-form, digital, stuff about?
A: The most direct answer is that a free-form or digital or whatever brand name they want to call it is a lens based on computer automated design or CAD. These lenses are created using very sophisticated computer programs and high precision tools to create special surfaces on both the front and back surfaces of the lens. The result is often a lens with a wider range of vision, increased optical quality and a prescription designed around the individual wearer and their frame. It is popular in progressives but can be done in high single vision prescriptions also.
Q: How do I know a frame fits me? Also see the Frame Fit Photo Gallery link above.
A: Look at 3 things. Width – Nose – Temple
Width: The temples or “arms” or “stems” should leave the front of the glasses and go roughly straight back and touch just before the ear. NO CONTACT with the side of your head!
Nose: Frames should feel comfortable on your nose. In plastic frames you want all or close to all of the frame touching the nose with no gaps and no single points of contact.
Temple: Make sure the temples are long enough to reach well behind the ear. In kid and petite frames make sure they are not so long they will be annoying.
Q: Is the anti-reflective coating worth the money?
A: Yes, a high-quality one is worth every penny. I you need to choose between a cheap AR or none choose none. A high quality AR will have a brand name and your ECP should be able to tell you what you are getting. Most high quality AR coatings come with a two-year warranty.
Q: Do I really need sunglasses when the sun does not bother me at all?
A: If you go outside you should wear glasses with UV protection. While many clear eyeglasses lenses protect you from UV damage, all sunglasses do.
Q: Does a polarized lens offer more protection than a well made pair of sunglasses without polarization?
Q: Should I get the frames with spring hinges?
A: Not necessarily. Many frames today have flex properties throughout the frame making the spring hinge unnecessary. Frames made of super-strong titanium may not need spring hinges.
Q: Do frames with spring hinges fit better?
A: NO! If a frame is fit properly the spring hinge will be closed unless hit or being taken on or off.
Q: My vision has not changed in years. Why should I get a new exam?
A: Because an eye exam is not about getting the prescription for glasses it is about checking the overall health of your eyes. A good eye exam can check for diabetes, glaucoma, retinal problems, dry-eye and many other MEDICAL conditions that can lead to blindness.
Q: Why can’t I take my old lenses and put them in a new frame?
A: This can be done but it is like finding a needle in a haystack. In the world today there just simply is not time to do it and it is not worth the money. Lenses are cut for a SPECIFIC frame to within a 5/100 of a millimeter of accuracy. Forcing the wrong shape in to the wrong frame is not going to be doing you any favor.
Q: Why was the person at the optical shop such a jerk, acted annoyed, refused, rolled their eyes etc. when I asked for my PD?
A: If you are regular customer, get yearly eye exams, buy contacts and refer others to the store then that person should gladly give you your PD! If they do not they are foolish and rude. If you just wander in off the street and ask them to take their time to measure you for your PD so you can turn around and go and by your glasses on-line then you deserve to be treated rudely.
Q: Why can’t the optician tell how thick the edge of my lenses will be?
A: If the optician says, “There is no way to predict exactly how thick a lens edge will be.” Thank them and be happy you have probably found a competent optician! Lens edge thickness depends on material, patient PD, frame size, frame shape, the processes used to grind or create the Rx and of course the Rx itself. A difference of even 1/10th of a millimeter in any direction can cause a difference in edge thickness.
Q: Why do some glasses cost so much?
A: You are paying for a brand name frame, you are paying for the research and development for the latest in lens and frame material technology, you are paying to make up some of the gap in income loss from the shop taking insurance, you want the very latest style and you are willing to pay for it.
Q: Why did the optician look like they wanted to beat me with a stick and then toss me in a dumpster of hungry weasels when I kept comparing my old pair to the new pair I just got?
A: Because your prescription and/or frame changed! Of course things will look a little different between the old and the new pair. If they did not then you would not have needed a new pair of glasses. Yes, a change in frame can cause a change in vision even in the same prescription (due to different angles and distances from your eye). Remember YOU chose the Rx by saying 1 was better than 2 etc…
Q: Why can’t I get my Rx in those cool wrapped styles I see?
A: Depending on your Rx you may be able to but expect to pay well over $500 to get it done. Eyeglass prescription are created by the curvature of the lens. You cannot overcome physics just because you want to look cool. The higher your Rx the less likely it will be that you can get it filled in a “wrap” frame. I do NOT endorse any products however Bolle, Rudy Project and Oakley do offer some of their wrap designs in Rx.
LOL: A patient called and asked, “If I bring my glasses in can you fix them?” He replied, “Well I might have a much better chance that way instead of over the phone!”
LOL: A patient called and asked, “How much are your glasses?” She replied, “How much is a car?”
LOL: “No I did not use Super Glue on them.”
LOL: “I need a screw.”
LOL: A daily occurrence in an optical shop – A patient brings in a pair of glasses with both lenses out, the temples bent and the temple end cracked and says, “I just opened the case and they were like that.”
Consumers Guide To Buying Glasses Why Can’t I See Out of My New Glasses?
OK, this is a tough one and I could go on for hours… A competent optician working with your eye doctor should be able to trouble shoot a prescription problem, in one visit, 95% of the time. 5% of you out there need to remember that you see with your brain, not with your eyes and maybe your brain is not working quite right. That is not meant to be mean or sarcastic, it is quite simply the truth. Yes, you may be in that 5% group if you have been back more than twice for a prescription problem. If you have been back three, four, five times then you are in that 5%!
Vision is subjective not objective.
STOP comparing your old pair and any new pair. As stated above, as we age if your Rx changes you will gain and lose perfect vision in one area or another.
Vision is the result of the brain interpreting what it sees through BOTH eyes. STOP covering one of them and insisting there is a problem.
If you have a pair you like and work well for you then BRING THEM WITH YOU! when you take your new glasses back to the store.
Many small problems with a new Rx can be overcome with simple adjustments to the frame. This may seem a little odd but it works, it works!
If your prescription changed and it now calls for an add power but you choose to not go in to a bi-focal or progressive lens you are probably going to be unhappy! You are old, o-l-d, get over it.
Single Vision: If you are a routine prescription and you wear single vision glasses and you cannot see well out of your new prescription then chances are excellent that you need the Rx tweaked closer to what you were wearing previously and liked. Have your optician:
- Check the actual glasses Rx to the Rx written on your doctor’s prescription form. NOT to what they wrote on the job order form. Make sure it was filled correctly. Opticians are human and we make mistakes.
- Check the Rx against your old pair of glasses for any unusual discrepancies. They should look for large differences in axis, PD, OC, and cylinder power.
- Check your new pair of glasses with your old and have them adjust them to fit as close to the old ones as possible.
Note: In very rare instances a change in material can cause problems with an Rx.
Lined Bi-Focals and Lined Tri-Focals: If you wear a fairly routine prescription and you wear a lined bi-focal or lined trifocal and cannot see out of a new Rx then you will need your optician to run through the same checklist as above for single vision. However if the line is placed too high or too low they simply need to remake the glasses. Note: The height can often be adjusted a few millimeters up and down with the nose-pads on a wire or metal frame. Lenses made too high or low in a plastic frame MUST be remade.
After ruling out the checklist above for single vision:
Every progressive lens has special embedded proprietary markings and an individual fitting layout chart. They should use those marks and highlight them with a special pen. Then check that the lens measurements match those written on the job order form. Only then should they put the glasses on you and look at how they align with your eyes. Common errors (we are human) are fitting the distance area too high or too low or missing that one eye is much higher or lower than the other.
- There is a special catalog with all the proprietary markings that tells an ECP what progressive lens you have including the material it was made from.
- If you have worn progressive lenses before but cannot get used to your new ones it may be the design. Ask your optician to put you back in what you were wearing before or as close as they can get.
- As you age and your add power goes up, +1.25 to +1.50 to +1.75 to +2.00 the distortion in the rest of a progressive lens will increase. Sorry, that is just the way it is – you cannot overcome physics. Add powers over +2.00 are guaranteed to have some annoying distortion.
- If you are new to progressives be sure to try them a few weeks before giving up. If the motivation is there you may even want to try another design, perhaps even from a different company and maybe even from a different store.
- If you just cannot get used to them the store should put you in a pair of single vision or a lined bifocal instead. There should be no charge for the change but no money returned either.
Consumers Guide To Buying Glasses Glossary of Common Optical Terms
Any reputable optician or ECP should be able to explain, in simple terms, what you are buying. Here is a list I am compiling of terms you are likely to hear when you go to your doctor’s office or optical shop.
Aspheric: A lens that is designed with special curves that makes the lens thinner, lighter and provides better vision.
Astigmatism: All it means is that your eye’s cornea has two different curves on it. It is a scary sounding word for a very simple refractive condition. For a full explanation of astigmatism and axis you will need to become a member.
Plastic: Virtually all eyeglass lenses are now a type of plastic. A lens called “plastic” is one made from a material called CR-39. It is heavy and quite thick but is quite good for lower prescriptions, tinting and optics.
High-Index: A material that provides the thinnest (NOT LIGHTEST) possible lens for higher prescriptions. High-index lenses will have a number from 1.60 to 1.74. The higher the number the thinner the lens should be.
Trivex: A lens material that is lightweight, and has great optics. But – Can be quite thick in higher prescriptions.
Progressive & Transition —
Transitions Lenses®: Is a brand name for lenses that darken when you go outdoors. Transitions (the word) has become a generic term for darkening lenses. Darkening lenses are an excellent choice for anyone who frequently goes from inside to outside. Darkening lenses do not stay dark in a car so they DO NOT replace sunglasses.
Progressives: Also incorrectly called no-line bifocals or no-line trifocals. These are lenses that provide the full range of vision from distance to intermediate to near with no visible lines.
Polycarbonate: A thin, lightweight, impact resistant lens material with fair optics. Polycarbonate is used in over 80% of all eyeglasses because of its low wholesale cost, low weight and safety. It is NOT a high-index lens and it is NOT the thinnest lens available.
Non-Glare: Also called anti-reflective or AR is a special coating that allows more light to enter the eye. More light = More sight.
Single Vision: A lens for one fixed distance, not a bifocal, trifocal or progressive lens.
Distance: A lens or prescription for distance viewing only: Examples, driving, watching a football match, sightseeing.
Intermediate: A lens or prescription for intermediate viewing or roughly at, or just beyond, arms length: Examples, computer screen, grocery items on the shelf, sheet music on a stand.
Near: A lens or prescription for near work or less than arms length: Examples, threading a needle, reading fine print, removing a splinter.
Computer Progressive: Also called office progressive. A progressive style lens designed for only intermediate and near work. An office progressive will allow comfortable intermediate viewing with the head in its natural position. These only work in the office environment!
Free-Form: (Digital) (“3D”) A special computer generated technique of making a lens that provides the best vision. Lens may require special measurements be taken.
Digital: (Free-Form) (“3D”) A special computer generated technique of making a lens that provides the best vision.
Temple: You might call it a “stem”. The piece that holds the front of the glasses the chassis that goes back to your ear.
Prism: A technique using the eyeglass lens to alter the position of an image being viewed so it appears to your brain that it is in the correct place and in the same position as the other eye sees it.
PD: Patient PD or patient pupillary distance. The measurement between the center of the eyes (actually the eye’s visual axis). Can be measured from eye to eye called binocularly or from center of nose to center of eye for right and left called monocularly. Important in high prescriptions and for progressive lenses, not so important in lower prescriptions.
Fitting Height: The vertical measurement of where the distance portion of a progressive lens will be fit. Unique for every different set of glasses and every individual person.
Polarized: A sunglass lens that has a special filter that blocks a specific wavelength of light that we see as glare.