General Optical Reference Material

Transcription

1 General Optical Reference Material

2 Index Frame Measurement Information Pg. 3-4 Lens Styles Pg. 4-5 Lens Illustrations Pg. 6 Lens Materials Table Pg. 7 Lens Terminology Pg. 8 Fitting Different Materials Pg Frame Types Pg Base Curve Pg Lens Options and Extras Pg

3 Frame Measurement Information DBL: DBL stands for "distance between lenses." This measurement is taken from as the closest point between the right and left lenses and is measured in millimeters. Bridge: Bridge is the distance of the bridge of the frame and can be found on the frame along with the Eye size. Note: this distance is not always the same distance as the DBL. Therefore when ordering lenses from your lab, be sure to measure the DBL and don't just use the manufacturers bridge length found on the frame. A/ Eye: A/Eye size are synonymous terms for the same measurement, and this length is put on the frame by the manufacturer. See diagram above to reference this measurement. Our lab measures this length from inside of the bevel to the inside of the bevel. B: The B measurement is the basically the top of the frame to the bottom of the frame. (Our lab measures this distance from the inside of the bevel to the inside of the bevel. ED: When measuring the ED use the box method. See illustration below. We measure the ED as 2 x Maximum Radius. Note that different shapes will determine different ED measurements, however an ED measurement must be at least the same size or larger as the A measurement. ED=2 x Radius ED=2 x Radius

4 Pupil Distance (P.D.): Pupil Distance is the distance between the patients pupils, and usually taken with a pupilometer. Pupil distance gives the lens its horizontal location. Segment Height (Seg Height): Measurement in millimeters that determins where the distance prescription stops and the near power begins for bifocal, trifocal. Seg.Ht is measured different for progressive lenses in that you take the distance from the pupil down to the bottom of the lens. Geometrical Center: Absolute center of the lens. Optical Center: Not to be confused with the geometrical center; the optical center (aka O.C.) is the distance prescription focal point for the patient. Placement of the O.C. is determined by where the patient's pupil is located in terms of height of the frame giving the lens its vertical location. Bifocal Progressive Geometric and Optical Centers Lens Styles Single Vision Lenses Lenses used for distance or reading prescriptions only.

5 Flat Top 28 Bifocal (FT-28, ST-28) Bifocals are distance lenses with a segment of reading power added at the bottom. Flat Top 35 Bifocals (FT-35, ST-35) This version of a bifocal has distance power in the top of the lens and a slightly larger reading segment area. Round 22 Bifocal (RD-22) Bifocal with a completely round add power segment. Just as flat top bifocals come in larger sizes, round bifocals also come in larger sizes. For example RD-24, and RD-25 Double Seg Straight Top 28 This lens has two FT-28 segments within the lens allowing someone to read normally looking down through a segment and also allowing someone to look up through a segment for reading. This lens is popular with people who requirea reading power in the upper portion of the lens for professional purposes. Executive Bifocal Executive bifocals are great for people who like to have a lot of add power to read with. This lens has add power throughall of the lower part of the lens. See illustration. Blended Bifocal This unique lens gives the patient's vision a feel of a bifocal but cosmetically looks like a single vision lens because the bifocal is blended into the lens. 7x28 (Trifocal) Trifocals have a distance power in the top of the lens with an intermediate power and a reading power in the bottom of the lens. Trifocals come in larger segments as well, for example 7x35, and 8x35. Progressive A progressive lens allows the patient to see distance in the top, reading in the bottom and everything else in between. View illustration.

6 Single Vision Lens Illustrations

7 Lens Materials Material CR-39 Plastic CR-39 Polarized CR-39 Transitions Mid-Index 1.54 Mid-Index 1.55 Mid-Index 1.56 Mid-Index 1.56 Polarized Mid-Index 1.56 Photochromic Mid-Index 1.57 Polycarbonate High Index 1.60 High Index 1.66 High Index Photochromic Ultra High Index 1.70 Ultra High Index 1.71 Ultra High Index 1.74 Crown Glass Photochromic Glass Gray 3 Glass Tan 3 Glass High Index Glass 1.60 High Index Glass Photochromic High Index Glass 1.70 High Index Glass 1.80 High Index Glass 1.90 Index of Refraction ABBE Value UV Absorption Specific Gravity 1.498/ % % % % % % % % % % % % % % % % % % % % % % 4.02

8 Terminology Index of Refraction: The higher the index of refraction the thinner the lenses. ABBE Value: The higher the value the less chromatic aberration. (ABBE value of the human eye is between 43-45) UV Absorption: Amount of Ultra Violet light that is absorbed by the material. Specific Gravity: The lower the gravity, the lighter the lenses. Photochromic Lenses: Are activated by UV light, causing them to darken and block UV light. Because of this the lenses will begin to darken when any source of UV light is present. Fitting Different Materials When fitting a patient with glasses it's important to keep lens material in mind. Lens mateial can make or break a patients glasses literally and figuratively. It's very important to keep your patient in mind when choosing a material.topics to help decide the correct material for your patient include: Prescription Frame Optics Safety Daily surroundings UV Protection Lens Weight Price and more Choosing a lens material that is right for your patient can be confusing to your patient as they probably don't know any differences, however this is very critical in your patients satisfaction, health and safety.

9 Below are some reasons for each of the above topics as to why these are so important to keep in mind while choosing a material. Prescription: Choosing a material for the prescription is important so that your patient's desires are met. Cosmetically a patient's lenses can look very thick by simply choosing the wrong material. As shown above, the higher the index of refraction the thinner the lenses will become. Remember the old "coke bottle" glasses Mrs Johnson used to wear? Let's not re-visit that embarrassment, especially since we have the technology these days to get it right the first time. Plus you probably don't want them out and about telling the whole world that they picked up a great pair of glasses at your establishment when in reality those glasses aren't very flattering. Safety: Safety can be a huge concern with regards to the material of your patient's lenses. If you have a patient who needs "Safety" lenses, meaning they are approved by OSHA as being considered "Safety Lenses;" than there is probably a reason for this. Perhaps they work near machinery and need protection from flying debri, or your patient is a child and requires Polycarbonate (Safest most impact resistant material made). Lens Weight: Lens weight is always an issue if a patient has a higher prescription or a large frame or even worse both. When a patient has a large frame then there is more material in the frame making it heavier than a small frame with less lens material. Also if a patient has a high prescription the lenses will be thicker therefore adding more lens material resulting in heavy eyewear. Note: glass is the heaviest material available. Frame: Choosing a frame for your patient is crucial. Cosmetics are always important to the patient because obviously they would like to look good in their new glasses. Selecting a frame that matches the patients prescription is important as well. If they have a high prescription than a good idea may be selecting a frame that helps hide the lens thickness. Lens material is important as well if the patient selects a rimless frame. If a rimless frame is selected, than we always recommend a lens with a 1.59 index or higher.

10 Daily Surroundings: Something to keep in mind when considering lens material is daily surroundings, routines etc. If your patient is in an industrial like atmosphere while wearing their glasses than Poly may be the best route to take. If they are outside all the time, than selecting a material that is available with Transitions or Polarized lenses would probably be best. But if they are indoors and merely using their glasses for a little light reading or surfing the internet, than regular CR-39 plastic is probably all they really need. Ultimately determining the patients lifestyle is important. Price: One of the largest determining factors of lens material may simply be cost. High index materials are much more expensive than CR-39 plastic. Therefore a patient may be forced to have their eyewear made with a less expensive material. Optics: Clarity of the optics is obviously important so that your patient enjoys their eyewear. Glass has the best clarity of all of the materials, but it is also the heaviest and least safe. Therefore choosing a material for clarity can be a tough decision; plus getting a patient who has always worn glass to try and switch materials can be very tough to try and talk into a different material. UV Protection: Because so much eye damage is caused by UV radiation, UV protection is crucial to have. Therefore choosing a material with UV protection built into the lens can help protect your patient from this damage. Poly and high index already have UV protection built into the lens. However ordering a lens with Transitions or that is polarized will also automatically provide your patient with this protection. Bottom line when it comes to choosing a material for your patient health and safety are key. After that they can go with any of the other bells and whistles to add onto their glasses that will improve any off the above characteristics of their vision and economic budget.

11 Frame Types There are three different main types of frames and they are: Metal, Zyl, Rimless and then under the Rimless category there are two different types; Grooved Rimless and Drilled Rimless. Metal - Metal frames are simply frames with a metal all the way around the lens. Zyl - Zyl frames are frames that simply have plastic surrounding the lens. Rimless - Rimless frames are those that appear to not have anything completely surrounding the lens. Grooved Rimless: This type of frame will often times have the upper have of the frame sounding the lens a normal Metal or Zyl frame, and the lower have will look as though there isn't a frame around the lens. Grooved Rimless frames always have a groove that run the circumfrence of the edge of the lens. This allows the lab to insert a piece of clear string much like fishing line into that groove holding the lens into the frame. Drilled Rimless: Drilled Rimless frames are frames that are attached to the lens by drilling a hole or set of holes into the lens and attaching the frame with anchors, bushings, or nuts and bolts, etc. Metal Frame Zyl Frame

12 Grooved Rimless Drillmount Frame Base Curve (lens and frame) Lens base curve (BC) is the ammount of natural curve that the lens has. Frame BC is the ammount of natural curve that the frame has. Ideally you would like to have both BC's matching so that the lenses fit well inside the frame. However that isn't always the case, and it's very easy for a lens to pop out of the frame due to the BC's not being close enough for the lens to stay into the frame. Therefore it's important to understand the relationship between BC's and how they change as prescriptions change. See chart on next page.

13 9 8 x x Base 7 x x x x Curve 6 x x x x x x 5 x x x x x x x 4 x x x x x 3 x x x x x x 2 x x x x 1 x pl pl = both can share base curves Prescription As you can see from the graph above, - prescriptions typically have a higher base curve with a lower powered prescription. Well + powers are the opposite and have a higher base curve when the prescription is higher. Now this chart isn't exact, however it depicts the typical trends of those two lenses. The illustration below is a horizontal cross-section look and shows how the curve of the lens gets steeper as the BC increases. 1 BC 3 BC 6 BC 9 BC Lens Options and Extras Once you and your patient have discussed frames and lenses, it's also a great idea to discuss lens extras since this is a good area for you as the business to make extra money and your patient to absolutely love their glasses. Here is a list of typical extras ordered from patients:

14 Photochromatic Lenses Mirror Coating Change Nose Pads Polarized Lenses Scratch Coating Change Temple Covers Anti-Reflective Coating (AR) UV Coating Custom Shape Tint 1.0 Center Thickness Engraving Solder Drillout a screw Photochromatic Lenses - Lenses change from clear (or close to it) to a darker shade (almost sunglass darkness) activated by UV radiation. A very popular brand of this type of lens is "Transitions." These lenses also block 100% UV radiation. Polarized Lenses - Lenses that reduce glare due to the components of the lens redirecting glare away from your eyes. Polarized lenses are dark, come as sunwear only, and are very popular for the following activities; watersports, skiing, hiking, biking, driving, fishing, and many more. Polarized lenses also block 100% UV Radiation Anti-Reflective Coating - AR Coating is great for reducing eye fatigue and strain, glare, and optically helps a lens with a low ABBE value increases the quality of your vision. Most AR's come with some sort of scratch warranty as well. In fact the newest AR coating Crizal Avance with Scotchgaurd Protection has a anti - scratch coating included within the coating making it one of if not the most durable AR on the market. Tint - A tint can be made pretty much however the patient desires. Tints can be solid or gradient meaning that they can be one color all the way through the lens, or they can be one color but darket in one or more area than other areas. For example, your standard pair of sunglasses are typically a Solid Grey 3; which means that they are a solid density 3 all the way through the lens. If a lens is gradient than the lens is typically darker at the top of the lens and lighter towards the bottom. Density values range from either 1-3 or A-C: and they mean that the lower the number or letter, the lighter the tint, and the higher the number or letter the darker the tint. As stated before your standard sunglass is usually a grey 3 or brown 3 (or grey C or brown C). Mirror Coating - Mirror Coatings come as either a solid mirror or flash mirror. Solid mirror coatings are just like a normal mirror, if your wearing them your friends wouldn't be able to see your eyes, they would only be able to see themselves. A flash mirror however gives the lenses a flash look but the eyewearer's eyes are still noticeable. Mirror coatings are available in different colors so please call your customer service representatives to find out exactly which colors are available.

15 Scratch Coating - Scratch coatings are popular because they protect lenses from scratching to an extent. If you were to run your glasses over with a car, or let your dog chew them up, well then a scratch coating won't do much. However scratch coatings do protect lenses from normal wear and tear. TD2 is a very popular scratch coating brand. Scratch coatings will often come with a warranty as well. UV Coating - UV coatings are very important to the maintain the health of your eyes. Therefore we always recommend UV protection to all eyewear sales. Many times nowadays UV protection is included in many lenses already, however if it isn't than you may want to recommend a UV coating to your patient. Our UV coating is applied just like a tint and takes just a few minutes to help protect your eyes for the lifetime of the eyewear. 1.0 Center Thickness - This is an option that isn't for everyone simply because it's intended for those who have a higher prescription. If we grind the lenses to a 1.0 CT than the outer portions of the lenses will be thinner than if we run them normally. One problem that comes with grinding lenses with a 1.0 CT is that they can become too thin and that's a bad thing because the lense may break or chip, or just not fit in the frame. Change Nose Pads - Whether a patient has lost their nose pads or would just like a new pair, this is an easy procedure that gives the patient a feeling of a new or improved pair of eyewear. Change Temple Covers - Temple covers are typically made of a less expensive plastic and eventually wear down and break. Therefore patients will come into your office and request new temple covers and it's important to know how to change them. Custom Shape - Some patients will desire to have their lenses made into a custom shape. This is an option that is possible depending upon the shape. This is important to clear with your lab before you say yes to your patient. Some shapes are very easy to make while others aren't and a lab might vey well say no way is this possible. Therefore be sure and check with your lab to see if this option is available. Engraving - Engraving is an option that isn't requested very often but it can be a nice touch to a pair of expensive eyewear if the patient is willing to pay for it. Traditionally this is an expensive option simply because this procedure is done by hand. Some labs have a engraving maching that will do all the work for you.

16 Solder - In order to solder a frame you will not only need the equipment to do so, but frame soldering can be a tricky and difficult process if you don't have any experience with it. Frame soldering is a nice option to offer your patient if they can't afford a new frame. However it's important to keep in mind that even though a frame is soldered, that frame is no where near as strong as it used to be. It isn't uncommon for a frame to be soldered several times once it has been broken. Note: Titanium frames CAN'T be soldered. Drillout a screw - Because accidents happen a broken screw inside the frame isn't an uncommon possibility. However a very common possibility is that the frame can be ruinned while drilling the screw out. This process requires the screw to basically be drilled out by hand allowing for accidents to happen. Many times screws are made from a material that is more dense than the frame; therefore the drill bit will slip off of the screw and drill a hole through the side of the barrel of the frame ruinning the frame. Many times a lab won't drill out a screw unless they know that the patient is aware that this request is done at their own risk. Meaning that if they do break the frame the lab won't have to pay for it. If you have any qustions regarding any information within this packet of material, please contact your Sunstar Opticl Company Sales Representative or Customer Service Department. Information within this spreadsheet is intended for use of Sunstar Optical Company customers only.