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Prescription Sunglasses and Sports Eyewear:
This page is here to help you learn a little more about prescription sunglasses. You don't really need to know everything on this page before you order a pair of prescription glasses. But the information below will make it easier for you to make informed choices. And we hope you remember ADS Sports Eyewear the next you have an opportunity to impress someone with this information in a game of Trivial Pursuit.
We love a challenge. If you have a difficult prescription, or you've had difficulty buying prescription-sports glasses in the past, we want to help. Just tell us what activity the glasses are for and send us your prescription. We will determine which glasses are most compatible with your prescription and send you a list of options. We will also give you our recommendation and tell you what we based it on. Email your request to Rx@ADSeyewear.com or fax it to (972) 398-3889. You are under no obligation, and there is no charge for this service. If your prescription is so far off the chart that it changes the standard prescription price, this exercise will also give us an opportunity to calculate that into the options we give you. If your prescription is outside the boundaries of -4.50 to +3.00 you may want to select your glasses from our Six Base Sunglasses page. Six base frames are just a bit flatter than 8 base frames. This will make the lens thinner, lighter, and easier to get used to.
There has never been a better time to shop for prescription sports sunglasses. New Digital Prescription Lens surfacing equipment eliminates the "fishbowl effect" that people used to associate with putting a prescription in a wrap style sunglass frame. And nobody knows more about prescription sports eyewear than ADS Sports Eyewear.  Filling in the On-Line Rx Form:
Once you are done shopping and click the Check Out link from the Shopping Cart you will see an icon like this one on the bottom of the page. ------> The instructions below apply to this form:
If your prescription is a simple sphere, you only need to fill in the first and last columns of this form. The completed form will only have the Sphere and PD filled in, and it would look like the form below:
If your prescription does not indicate the "PD Measurement", you should contact the last place that sold you prescription eyewear and ask for it. PD stands for Pupilary Distance, or the distance from one pupil to the other measured in millimeters. This number is used to align the optical center of the lens with your eye. A Monocular PD Measurement is preferred. This consists of two separate measurements from the center of your noggin to each pupil. A binocular measurement will be one number that represents the distance from one pupil to the other. A binocular measurement assumes that your head is symmetrical and that your nose is exactly in the center of your face. Examining doctors rarely write this measurement on your prescription form, but any store that has sold you prescription eyewear will have it.
We realize this can be confusing. And different doctors write the prescription in slightly different ways. Don't worry. If you make a mistake just call us. We can fix it. If you'd rather not bother with this at all just call us. We are always happy to take orders over the phone.
If you'd like to know more about what the numbers in this form mean there is a summary printed below titled Understanding the Prescription Form. This section was designed to be easy to understand. Let us know if we succeeded. .
Delivery time:
It generally takes about 10 - 14 days to finish prescription lenses. Mirror coatings can add a few days. Oakley Prescriptions and Maui Jim Prescription sunglasses have been ready much faster than this, but they still tell us to tell you to expect a couple weeks. Feel free to contact us once you've selected your glasses and we will give you a more specific guestimate. Prescription returns:
Prescription eyewear cannot be returned for a refund, but don't worry. We will do everything we can to get you the perfect pair of glasses. If we make a mistake filling your prescription, we will promptly make it right. Even if the problem is the fault of the manufacturer, we will handle the problem for you until it's rectified. Simply follow the guidelines listed in our Return Policy. If on the other hand you send us the wrong information, we will still fix the problem just as fast as we can. We may also get charged for the additional lenses. This would be another good reason to fax us a current prescription. Try before you buy:
Because prescription glasses are not returnable, you may want to make sure you like them before we start grinding lenses. To help facilitate this, we give you an opportunity to try out a non-prescription version first. To receive a try-out pair of glasses, select "Send a try-out pair first" in the drop-down menu that asks "When should we start". Your credit card will be charged for the frame, but you will receive 100% credit when it is returned. Your only expense for this service is the cost to send the glasses back to us.
Fill in the prescription form just as you would if you had ordered prescription lenses. This will give us an opportunity to check the compatibility of the glasses you chose with your prescription.
If you like the glasses, email us or call 866-829-6522 and confirm that you want the prescription version. Then return the plano glasses in the same box that we used to ship them to you before they start looking used. (You have up to 10 business days to return the try-out pair.) Include all the original documentation and accessories that were with the glasses when you received them. Naturally, if we don't get the plano pair of glasses back, or if they are not in re-sellable condition, you will be charged for those as well. For this reason, we recommend insuring glasses in transit.
You're under no obligation to buy, there is never a restocking fee, and we don't want you to keep anything that you're not enthusiastic about wearing.
To help expedite this process, we may not send your try-out pair of glasses in the exact color that you ordered. We will match your color preference as closely as possible, but our goal is to let you check out the feel and fit of the glasses. If you REALLY need to try out glasses that will be identical to the prescription version that you want, drop us an email and let us know. If we do not have what you want in stock, we will promptly order them and ship them to you as soon as we get them. All shipping from ADS Sports Eyewear will be done at no charge to you.
Understanding the Prescription Form:
This information is at the bottom of the page because it's really the last thing you need to know when ordering a pair of glasses. But we think you'll be a better person for reading it, and educated consumers are more fun to work with.
For starters, OD and OS translate to right eye and left eye. They're from the Latin words Oculus Dexter and Oculus Sinister.
Props may help us illustrate these next points. So set a round plastic bowl in front of you and imagine that it's your eye. If your bowl has the correct curvature, images will come into focus clearly on your retina. Congratulations, you're emmetropic and you don't need corrective lenses. If the curve of your bowl is too flat, images will focus on a spot somewhere behind your retina, and you're farsighted or hyperopic. If the curve of your bowl is too steep, images will focus in front of your retina, and you're nearsighted or myopic. Hyperopes correct their vision with a plus lens. This is a magnifying lens, so the center is thicker than the edges. Myopes correct their vision with a negative lens that is thicker around the edges than it is in the center.
Rimless eyewear may look better on hyperopes because their plus prescriptions are thinnest around the visible edge.
So far, these near or farsighted illustrations only explain simple spherical variations that are corrected with simple single-power lens. Patients with these vision impairments can simply complete the Prescription Information Form by entering the SPHERE and Pupilary Distance.
But if you go back to your plastic bowl and gently push the outside edges toward the center with each hand, you create astigmatism. Your bowl has a different radius of curvature from left to right than it does up and down. The difference in curvature is the amount of CYLINDER you will need in your prescription. The angle of the curve down the center of your bowl is the AXIS of that cylinder.
Most prescriptions are written with the steepest curve as the sphere. The next number is the cylinder. The minus sign before the cylinder indicates the difference in curvature from this steepest curve to the flattest, which will always be 90 degrees apart.
This is called negative cylinder format. A few doctors still write prescriptions the other way around, with the flat curve listed in the sphere, a plus sign before the difference in the other axis, and then the axis location is noted 90 degrees off of what the other format would indicate. Either format will result in the same lens. Doctors who write prescriptions in plus cylinder form were probably nonconformists in the 60's also.
The ADD column is for bifocal or progressive lens wearers. As we age, the crystalline lens behind the cornea loses some of its flexibility. It's a natural part of the aging process, and sooner or later it affects everybody. To focus on something close to your face, this lens must flex into a tighter arch. As it loses flexibility, it loses its ability to accommodate this tighter focus. This is called presbyopia, and it has nothing to do with being nearsighted or farsighted. Hyperopes (farsighted), myopes (nearsighted) and emmetropes (no correction needed) will all eventually lose their ability to focus on things close up.
The last column on the prescription form is for Pupilary Distance, or PD. Your binocular PD is the distance from the center of one pupil to the other. The form above requests your monocular PD, which divides your binocular PD at the bridge of your nose. Faces are not always symmetrical, so these numbers may not be the same. This measurement is used to insure that you are looking through the optical center of a lens.
If your prescription includes an ADD power, your prescription may have two PD measurements. One is your Pupilary distance when you look at a distance. (Sometimes called FPD or DPD, for Far or Distance Pupilary Distance.) The other number is your PD when you focus on objects closer to your face. This Near PD is generally about 1.5mm less in each eye than your Distance PD.
Congratulations. We are sincerely in awe of anyone who has the tenacity and thirst for knowledge to make it this far down the page. Frankly, we think you're a little weird, but we're still really impressed.
You can't really understand prescription lenses without some knowledge of diopters and base curve, but I'm betting this is where you start feeling the need to go surf somewhere else. So click here, buy a pair of glasses, then come back and finish the page.
Welcome back. These last two points deal with the curvature of a lens. The unit of measure used to indicate the strength of a lens is diopters. The strength of the SPHERE, CYLINDER and ADD powers are all are given in diopters.
 A Diopter is a measure of curvature. If you had a lens with a 1 diopter curve and extended that curve all the way around until it completed a circle, your circle would have a radius of 530 millimeters. This is just under 21 inches. If you sliced off a section of this sphere and ran parallel beams of light through this 1 diopter lens they would converge to a single point 1 meter behind the lens.
So just to reinforce this, let's say our next lens is three times stronger. Now we have a 3-diopter curve, so the radius of a circle created by extending this curve all the way around will only be about 7 inches, or one third the size of a 1-diopter curve. If parallel beams of light pass through this lens, they will come to a focus in 1/3 of a meter, or 3 times faster.
The lens shown below illustrates why people who hate adding positive and negative numbers together shouldn't be opticians. The front curvature of a lens is on a convex surface, so the curve is positive. The back surface is concave. A concave surface will deflect light in exactly the opposite way as a convex surface would. For this reason, the curvature is measured as a negative. Therefore, a plus seven-diopter front curve and a minus 6-diopter back curve result in a plus one-diopter lens. The front and back curvatures are added together to arrive at the power of the lens.
If the front curve stayed the same, and the back curve was increased to minus nine, we would have a negative lens. The power would be minus two, and the edges would be thicker than the center. This prescription would be for a myopic or nearsighted person.
Base Curve
Base curve is a term that should be understood by anyone who wears any kind of glasses, prescription or not. Sunglass manufacturers often display terms like base 6 or 8-base in the description of their products. This indicates the curvature measured in diopters on the front side of the lens. If the lens is a plano lens (no power), the back curvature will be the exact opposite of the front. Many people find that their eyes become accustomed to a base curve, and getting used to new glasses that have a different base curve requires some time.
This is especially true of people who wear prescription glasses. If you've ever been more comfortable wearing your old glasses than your new ones, have the base curve checked in both of them. Any optician with a lensometer or a lens clock can do this in no time. If you can identify a base curve that your eyes prefer, note this in the comments section of the checkout page. This will help us create the most comfortable glasses possible for you.
High Minus Prescriptions in Big Wrap Glasses
We are often asked if we can put prescriptions stronger than –8.00 or –9.00 in frames with a big 8-base curve on the front. The answer is yes, we can do almost anything. And with the new digital surfacing techniques for prescription lenses the optics in these lenses will be amazing. But you should use care in selecting a frame with a big wrap when you have a strong prescription.
The term “8-base frame” indicates that the eyewear frame has the same curve as a +8 Diopter lens surface. This curve is about the same shape as the average person’s head. Therefore sunglasses with an 8-base curve typically provide the best protection from the sun, they fit better on your face, and minimize “bounce-back”. (Bounce-back refers to the sun hitting the back of the lens and reflecting into your eye.) This shape is even more important for high-speed sports like motorcycling or sports like golfing and boating where you could be exposed to UV rays for hours at a time.
If you memorized the Diopter information above, you know that a high minus prescription in a frame with a +8 curve on the front will create a very steep back curve and a lens that is very thick on the outside edge. For example, a –6.00 prescription lens in an 8-base frame will have a back curve that is –14.00. The steeper this curve is, the thicker the lens will be. Selecting a rimless or semi-rimless design may expose more lens thickness than you would like.
High index lens materials are often used to flatten lens curves and reduce lens thickness, but this is not an option for most sports eyewear. High index lens material will bend light more efficiently and make the lens a little flatter and thinner. But all of the higher index materials are breakable. Having a lens that can shatter is not what you want in front of your eyes for sports activities or motorcycling.
If you made it to the end of this page, you're our hero. Most people in our office pool were betting that no more than two or three people a month would actually get to the bottom of this page. We're thrilled that you took the time to finish it, and we would be equally thrilled to hear from you. Click here to let us know you made it. If you still have time, let us know if this information might ever be of any value to you. We will reply with a coupon code worth 10% off your next purchase. (This is not an auto-response. We actually read these and reply to each email. So allow 24-hours for a response. If you buy something before you get your coupon code we will just refund the discount.) |
