Free Form or Digitally Surfaced Lenses

What is a free form lens and why is it different than other lenses?
       Free form is a computerized design and manufacturing process.  Unlike conventionally surfaced lenses, which use a wheel embedded with fine diamond particles to roughly grind a prescription into a resin lens blank, followed by a fining and polishing process, the free form process precisely cuts the prescription in the lens blank using a single diamond point guided by the computer software program.  There is no fining or polishing needed in free form manufacturing. The computer program is designed to make a distortion free lens.
       Free form processing enables lenses to be made to a .001 Diopter power accuracy, which is about 25 times more accurate than a conventional lens.  This gives lens designers the ability to attempt to reduce lens abberations even more than in the past.  This is why you'll hear claims of less peripheral distortion and blur.  Also called HD lenses.
       Some of these lenses customize the design by utilizing different measurements of the frame.  If you wear a progressive or "no-line" bifocal, you no longer have to worry about using a larger frame or one that has a large vertical measurement because the free form program chooses the correct design for the frame.
       Another feature found in these lenses is the compensation for things like vertex distance (the distance from your eye to the front surface of the lens), face form (the curvature of the frame) and pantoscopic tilt (the angle of the lens while wearing the glasses).  These factors can be measured by the optician and their contribution to the lens power errors can be compensated.  The result is a lens that is completely customized for the wearer.  Some premium sunglass lines, such as Oakley, Nike, and Maui Jim exclusively use free form lenses.

Flak Jacket by Oakley

Most people will see through a conventional lens just fine, digitally surfacing makes that lens better.  While educating the patient in the office, I'll use the comparison of video technology.  If you're old enough, you remember having a black and white TV.  This worked great until you got your first color television.  This was followed by the flat screen which gave a wider angle to view the TV and now we have the HD TV's which have the widest viewing range and clearest picture.  Every TV you had worked fine, technology made it better.

            For people who had problems in the past with standard progressive lenses because of peripheral abberations or distortions when moving your head, you would be an excellent candidate for a free form progressive lens.  As I mentioned earlier, they a custom designed for maximizing your viewing area and minimizing distortions through the free form program.
       Digital technology will cost you more.  The software to make the lenses is expensive and they will do much more for you.  Remember, most of you rely on your glasses to see almost every waking hour of the day, this is a very good investment, just like that HD TV.  Make sure to add a quality anti reflective coating for the best vision you ever had!

Transitions Vantage

      Last year, Transitions Optical, Inc., introduced it's newest family member.    Added to the rest of the Transitions line: Transitions VI, Transitions Xtra Active, and now Transitions Vantage.  http://www.transitionsvantage.com .

What is Transitions?
It's a type of photochromic lens, one that will darken when exposed to sunlight.  Depending on your lifestyle and needs, you can get regular Transitions, which a almost clear indoors and when outside, will act as a very good comfort lens by removing about 60% of light.  Xtra Active works the same, except the lens always has at least a 20% tint indoors and will get about 10-15% darker outdoors.  Transitions also claims it will darken slightly in a car.  This is probably due to the existing tint in the lens plus some residual tint from being outdoors first.
The Transitions Vantage lens also changes outdoors, starting with about an 8 % tint and darkening about 70-80%.  However, when fully darkened, the lens becomes polarized.  This will greatly reduce the amount of reflected glare outside. (see blog entry on polarized lenses).  Remember that the lenses darken only when exposed to ultra violet light (direct sunlight).  Your car windshield blocks UV light, therefore, your Transitions lenses will not darken very much in a car.

Today, I received a new pair of glasses with Transitions Vantage lenses to make a comparison between the regular Transitions and Vantage. Unfortunately, I was not able to tell a difference between the lenses and my polarized sunglasses are much more effective for glare.  While the concept of the lens is excellent, the performance was lacking.
This is the first time I've not been able to endorse a product based on the company claims, but true to my blog, it will allow for an informed decision.  Transitions is a great product, I've been wearing for a few years, but this latest lens fell short of expectations for me.

Bio True One Day Contact Lenses

 Bio True One Day is the newest generation in the single use contact lens market.  It uses Bausch & Lomb's Hypergel material.  B&L says that this is the first contact lens bioinspired by the human cornea.

What makes this lens so special?
The contact lens is made of only 22% material and 78% water.  This is the same water content of the human cornea.  The lens surface is very similar to the lipid layer of you tears.  This is what keeps your eyes from drying out.  This is what makes Bio True One Day so comfortable.  My personal experience with the lens is that they were still comfortable after 14 hours of wear!  FYI, I don't wear contacts because of comfort issues.
It also has Bausch & Lomb's High Definition Optics which help reduce halos and glare, especially at night.

How much do they cost?
Bio True one Day contacts would be more expensive than standard single use lenses, because of the newer lens material and technology.  They are an excellent lens for problem eyes, such as,  chronic dryness, post LASIK, flat corneas, or someone looking for better end of day comfort.
Currently, there are rebates available to help with the cost too.  I would figure less than $1.50 per day after the rebates.

They currently are only select doctors that have the contacts with a national rollout early in 2013.  You can find a doctor in your area by getting on the Bio True web site at  http://www.biotrue.com.

Eye Conditions

http://www.webmd.com/eye-health/ss/slideshow-eye-conditions-overview
Although, I said at the beginning that this would be only about products, I did come across something on Twitter that I want to share.  This informative link is courtesy of Bausch & Lomb.

Cleaning Your Eyeglasses

   Next time you pick up your new pair of glasses, notice how clear everything looks.  Even if there was little or no prescription change, you'll see better.  The reason for this is that the lenses are crystal clean, no scratches, crazed coatings, or dirt and smudges on the lenses.  You want to try to keep them this way for as long as possible.  I'd like to give you a few tips.
    1) Use the microfiber cloth that your eyecare provider gives you.  They really work, some better than others.  You can use these dry on your lenses, provided your are just removing smudges and fingerprints.
    2) Use an alcohol free lens cleaner to remove dirt from the lens or if you've been told not to wipe the lens dry.  Also, a quick rinse under warm tap water or mild dishwashing liquid works well.  Still, use the microfiber cloth to wipe the lens off.
If your cloth gets dirty, either hand wash it and put it in your dryer (without a dryer sheet) or get a new one.

Lens cleaner from Carl Zeiss.

     The microfiber cloth protects scratch resistant coatings and anti reflective coatings.  Avoid paper towels, tissues, etc. because paper is either too abrasive or contains lotions to soften it.
     This is at minimum, daily maintenance.  As the glasses get older, more maintenance is needed to preserve your investment.  Nose pads on metal frames may begin to oxidize, or turn green.  This can be easily fixed by a visit to your optician and have him replace the nose pads with new.  If they are attached with screws, make sure that they get replaced as well.  The screws are usually what turns the pads green in the first place (even on most titanium frames).  There may be a small charge to do this depending on where you go.  Our company will replace them for free.  Something that you can do at home, if needed, is to use a soft bristle toothbrush and a few drops of liquid soap and gently scrub around the nose pads and edge of the lenses.  This is something I do at work frequently.
      If your glasses are getting old and crusty looking and need more of an overhaul, your optician can remove the lenses and clean them, replace screws and nosepads and even the plastic pieces that go around the ear. They also put the frame in an ultrasonic cleaner, just like a jeweler would clean your rings.   There may be a nominal charge for all of this, as well, since it requires more parts and time.
      At any rate, this will hopefully prevent the dreaded, Nose Cheese, the disgusting oil and dirt buildup I see on a regular basis and keep your glasses looking good!

Which Soft Contact Lens Should I Buy?

      With so many soft contact lenses available right now, I'm sure you're confused on which is the best.  I'm not going to be able to answer that either because one lens is not the best for everyone.  That is why I discourage "lay" people from telling me what they want to buy because they saw it online or their friend wears XYZ brand ad they have to have it.  You should let your optometrist or optician determine the best options for you.  That being said, I'll go over some more popular brands and lenses I use on a regular basis.

Hydrogel vs. Silicone Hydrogel 

Hydrogel lenses:

 

        

 have a percentage of water content (between 38% and 70%) to make a softer material.  Examples of hydrogel lenses are Acuvue 2, Soflens 38, Freshlook, Frequency, and all single use or "daily" contacts (except Acuvue 1 Day TruEyes).

Some of the properties of hydrogel lenes are that they are lower *Dk or oxygen value (usually between 15 and 45Dk).   They are less healthy for the eye, increased chances of corneal edema and blood vessel growth to the cornea, due to low oxygen values.  Although this doesn't seem to be a problem with contacts that are replaced daily.  They are less expensive and tend to be drier on the eye.

              

 Silicone hydrogels: 

They have water content like hydrogel lenses.  The percentage of water ranges from 24% to 60%.  Like the name says, it utilizes silicone combined with the hydrogel material to achieve a higher oxygen lens.  The Dk, or oxygen, values range from 78 to 160.  Since silicone is a poor wetting material, manufacturers need to "hide" it.  Moisturizers or surface treatments are typically used to do this.  Examples of silicone hydrogel lenses using moisturizers are Acuvue Advance, Acuvue Oasys products and the single use TruEyes.  Contacts which use surface treatments are Alcon's Air Optix products and  Bausch & Lomb's PureVision and PureVision 2 HD products.  CooperVision's Biofinity line uses a more natural way of using silicone without the need for moisturizers or surface treatments.

 Silicone hydrogel lenses are healthier for the eye (especially for overnight or extended wear) due to the higher oxygen permeability.  And if you do wear a contact lens overnight, make sure that your eye care practitioner has already determined that you are able to do this safely and the lens has FDA approval for overnight wear.  It is also more important to rub the lenses while cleaning after removal and they seem to be more sensitive to certain solutions.

What is Dk and why should it concern me?

The Dk value is the amount of oxygen permeability of a lens material.

A higher Dk lens will decrease the chance of corneal edema (corneal swelling)

and also the growth of blood vessels in the cornea.

So, you can see that there are a number of good contact lenses available to you.  My suggestion would be to get a lens that allows enough oxygen for the type of wearing schedule that you plan to use, unless that choice is a single use lens.  With a daily replacement lens, make sure it is comfortable.  I hope this helps!

  

                

"How much do glasses cost?"

This is probably the most open ended question I get during the course of a day.  It's  one of the few questions I can't answer without asking a number of questions back.  I'm sure you've heard that "We have frames that "START" at $____.00 and lenses that "START" at $____.00".  Your chances of walking away with this price are virtually zero.  Most places will have some type of pricing formula, based on cost.  A rule of thumb, less expensive frames are usually pretty basic styles using basic materials.  More expensive frames are generally more stylish and may use special materials, like titanium or memory metals.  Lens pricing is slightly different but pricing is based on basic versus material and options.

"How much will my glasses cost?"  I still haven't answered the question, and probably still won't by the end of the blog.  My advice to you is to have an idea what you want with a pair of glasses.

If you have a mild nearsighted prescription and you want a basic pair of glasses, to have in case your contact lenses are irritating or just don't feel like wearing them,  you will probably be the one that can get something at the "Starting price".  You might pay $25.00 to $100.00 for the starting price on the frames.  You may even be lucky enough to find a "Clearance" section with even deeper discounts.  If you are more fashion conscious or will be wearing glasses more often than once in awhile, you may want to upgrade to the next tier of frames.  This could be in the $100.00 to $150.00 range.  If you want to the high end designer glasses, memory metals, titanium, etc., be prepared to pay in excess of $200.00 to $350.00 or more on these frames.  Remember, it's very important for any frame to fit well and be comfortable when you try it on.  Don't let an optician tell you that it's just a simple adjustment to make it feels better.  Have him/her make that adjustment while trying frames on if you're not sure.

      After deciding on the frame category you want to fit into, you'll need to figure out the same with lenses.  Lens pricing is very inconsistent throughout the optical industry, but some of the same principles apply.  Basic plastic or CR-39 lenses will be your least expensive lens.  This is usually what is advertised to get you in the door.  It's a good option for the occasional glasses wearer or budget minded person.  The next tier of lenses, would probably include polycarbonate lenses.  Polycarbonate is the standard material for the "thinner and lighter weight lenses".  It is also used almost exclusively with children's glasses due to its impact resistance.  I see more and more companies using polycarbonate lenses as their standard lens due to liability anymore.  There might be a minimal charge to go to polycarbonate lenses.
      If your prescription involves a stronger prescription, you may want to think about a High Index lens material or an ashperic lens.  These will be thinner and/or lighter in weight and should always be dispensed with an anti- reflective coating or a non- glare coating.  This material will create more light reflections due to it's density and flatter curves.  Expect these lens options to cost anywhere from 2 to 3 times the basic lens cost.  Transitions lenses could be another option.  This is a very good "comfort" lens while you are outdoors.  This could be another $50-$100.
       For those of us needing reading correction, you will need to decide on a lined bifocal or progressive lens.   Progressive or no line lenses can cost about $150 to $250 for standard plastic.  Remember if you have a stronger prescription, see the above paragraph, it still applies.  The newest progressive lens is called a free form lens or digital lens.  Without getting into too much detail, it's a digitally manufactured lens that with greatly reduce peripheral lens distortion and wider field of vision over standard progressive lenses. It is usually only available with and anti reflective coating. A great lens for smaller frames.  This could be $150 to $250 more than standard progressive lens.
       As you can see, I still haven't answered the question, but hopefully have given some help in what you can expect to pay.  Although it doesn't happen everyday, I've had people spend over $1000 dollars on one pair of glasses.
       Don''t be afraid to ask for discounts, AAA, senior citizen, certain health insurances can have discounts associated with them.  Also, if you are in the market for an extra pair, such as sunglasses, computer glasses, or just a spare, there might be 50 to 75% off of the second pair.
      FYI....I've decided not to include internet prices due to the fact that they are not regulated as of right now.  I don't see internet eyeglasses as a good option since studies have shown that accuracy is suspect, due to inaccurate self measuring techniques.