Frame Materials

In this blog, I'd like to talk about different frame materials that are used and some advantages and disadvantages of each. This will focus mostly around the different types of plastics and metals used in the industry today.  There are some unusual materials such as wood, bone, and rubber, but these are very specialty types of materials and usually very expensive.

Plastics                                                                            

The most widely used plastic material in zyl (or zylonite), this material is made of cellulose acetate.  Zyl has good "toughness", a deep gloss and high transparency.  It can be mixed with colors to produce about any color of the rainbow.  All of this makes it a good material for frames.  The material is also pliable when heated and can "shrink" when quickly cooled.  Frames made of zyl are typically injection molded, however, when you have a color blending such as a tortoise shell color, these are usually cut from sheets of plastic.

Another type of plastic resin is propianate.  It is a nylon based material which is very lightweight and hypoallergenic.  Propianate is usually clear and the surface is treated to create the different colors of the frame.  It also doesn't accept heat like zyl does.  Usually when inserting lenses, the frame is not heated, the lenses are put into a frame at room temperature.  Adjustments to this material should be done with very little heat or the use of a frame warmer.  

Back in the late 1940's, nylon was introduced as a frame material.  Nylon was very lightweight and comfortable.  The problem with pure nylon was its brittleness.  Also, it was very difficult to adjust.  Nylon blends were invented to adress the problem of strength.  Now, most of our sport frames (such as Rec Specs) and alot of sunglasses are made from these nylon blends.  They are typically made of gliamides, which are very resistant to hot and cold and are more flexible, yet also stiff.  The "wrap" sunglasses are usually made of these nylon blends because it's the best material to hold the shape.  Nylon blends are still difficult to adjust.

With all plastic frames, it is best to heat the frame slowly and evenly to avoid pitting or melting the plastic.  Stir the glass beads and heat only the part of the frame that needs adjusting by placing it about an inch below the surface, constantly moving it around.  This will apply the heat to the frame more evenly.

 Metals                                   

                                                               

As with plastics, different types of metals are used in the making of frames.  The most common is Monel.  Monel covers a broad spectrum of metals.  They tend to be very easy to shape.  The problem with monel is that if the metal is not coated with a nickel free plating, it can be corrosive, especially to sensitive skin.  Monel is also the most economical metal used.  It tends to make the cost of the frame lower.

Stainless steel is a lighter weight metal.  Stainless steel frames tend to be slightly thinner than monel and stronger.  Stainless steel frame can be a good option for the patient that has a reaction to monel or more corrosive metals.  Most stainless steel frames are nickel free and thus hypoallergenic.  This make a more cost effective alternative to titanium (which will be mentioned next).  Stainless steel contains certain amounts of chromium which gives it its corrosion resistance.  The more chromium in the frame, the best its resistance to corrosion.

Titanium, again, is a lightweight metal that is extremely durable and hypoallergenic.  We all know of titanium's medical uses because of its non corrosiveness and strength.  Titanium is also used in aircrafts and the Apollo and Gemini space capsules because of it being so lightweight.  Originally, titanium was only available in a silver gray color.  With the developement and popularity, titanium can produced in a variety of colors for a clean, more contemporary look.  One thing to remember is that all titanium frames are not all 100% titanium.   Some are made from an alloy that is a combination of titanium and other metals, such as nickel or copper.  This is done to reduce the cost of a titanium frame.  A frame only needs to be 50% titanium in order to be labelled that way.  Titanium cannot be soldered should it break.

Flexon  is a titanium-based alloy. This unique and popular material, which is proprietary to the eyeglass manufacturer Marchon, is called a "memory metal" because it can go back to its original shape if damaged. Frames made of Flexon come back into shape even after twisting, bending and crushing. Flexon frames are lightweight, hypoallergenic and corrosion-resistant.  There are other versions of this available from other manufacturers.

Aluminum is also used as a lightweight alternative metal.  Aluminum is also highly corrosion resistant.  Its the most abundant metal in the world, however, it seems to only be used in very high end frames due to the unique look it creates.  Pure aluminum is actually soft and weak, but commercial aluminum with small amounts of silicon and iron is hard and strong.  Aluminum frames usually are very stiff and retains shape very well.

Allergic Reactions to Frames   

Some frames can cause an allergic reaction.  This is most often seen as either a reddish colored rash on the sides of the head (wear the temples touch the head), the cheeks and/or nose (wear the frame might rest on the face). Also, the pad arms and screws of the frame may oxidize or turn green.   If metal frames cause a reaction, nickel is usually the culprit: most metal frames are made of a nickel alloy. Other metals used include: aluminum, stainless steel, titanium, zinc, copper, beryllium, gold and silver. Stainless, titanium, gold and silver are usually hypoallergenic.

Some people are allergic to the nose pads on metal frames. Most are made of silicone or acetate, but they can also be made out of polyvinyl chloride (PVC), nickel, titanium or rubber. Silicone is tricky: certain silicones are hypoallergenic (such as medical silicone), but others can trigger allergic reactions. Both PVC and titanium are usually hypoallergenic. 

Most plastic glasses are made of zyl (also called zylonite, acetate and cellulose acetate) or propionate. Other materials used in plastic frames include: polyamide, nylon, polycarbonate, carbon and Optyl (a brand of epoxy resin). Propionate, polyamide, nylon and Optyl frames are all considered hypoallergenic.

From my useless knowledge vault

The Chinese invented eyeglasses.  Marco Polo reported seeing many pairs worn by the Chinese as early as 1275.  That is 500 years before lens grinding became an art in the Western World.

Bausch & Lomb Trip

The Bausch & Lomb trip was an amazing experience.  Aside from the reason that I was there, to help with customer service, I learned alot about contact lenses in general.  I did not receive any product info, so I can't pass that along.
We started the day by being picked up at the hotel in the morning and going to the B&L Vision Care facility on N. Goodman St. in Rochester, NY.  I dropped my things off and we immediately went on a plant tour.  First stop was the Development and Research Division.  I was able to see how a vial of unknown material becomes a contact lens. It's amazing everything that goes into creating a material that can be worn on the eye.  They need to take the material and figure out how to process the material for manufacturing, how to cure it, store it, mass produce it so it is almost 100% consistent, put power in the lens, edges for comfort, tinting, packaging,  etc...And if any of these fail, they need to find out why and start all over again.  After going through the labs, we met all the customer service reps.  They take thousands of phone orders per week, process internet orders, talk to consumers and have a professional consultation deptartment.  Busy group of people!
After lunch, we convened to a conference room and got down to the business at hand.  Sorry, I can't divulge anything we talked about, I signed privacy papers.  But it was a very productive afternoon.  They capped of the day with dinner at Pier 45 on Lake Ontario.  I didn't have much time to do anything afterwards, I had a 6:00am flight the next morning.   I'd like to go on record to thank all the people from Bausch & Lomb to make this possible.  My goal is to take what I learned and pass it along to others.
My next blog with be on contact lens solutions and what could be best to use with your contact lenses.  See you then!

Bausch & Lomb

It's been awhile since I published a blog.   I need to stay on top of this more.  Next week,  Bausch & Lomb, is sending me to their Rochester, NY facility to attend a conference to help them with customer service. I'm exciting about being chosen to do this.  They have recently introduced some new products and will have something new in late August or early September.  I'll keep you informed.  I expect to get a good amount of product info so my next blog will be on one of the newer  PureVision products.
Also, in the future, I would like to supply information on contact lens solutions and which might be better for certain lenses than others.  Not everyone will be in agreement with me, but I have permission from a website to use their data regarding solutions.
Make sure you check out the poll and offer any suggestions on topics you'd like to hear about.

Polarized Sunglasses

As promised, and well overdue, today's topic will be polarized lenses. There are many different colors available in a polarized lens, however, I'll be focusing on the sunglass colors and tints.  I'm sure we all have heard the term polarized but are not sure how they really work.  A polarized lens will virtually eliminate glare when compared to just a darker tinted lens.  Glare would accurately be defined as reflected light from the sun.  We see glare off water, snow, car windshields, windows, sand on the beach, or an asphalt road while driving.  To see what a polarized lens will do for you, visit the Vision-Ease Co./Coppertone Lens website for a demonstration.


A polarized lenses is not just a tinted lens.  It's 2 clear, thin lenses (the first lens is usually 0.5mm to 1.0mm thick, the second lens will have a minimum center thickness of about 1.0mm), wafered in the middle is a tinted, polarized filter.  This filter will block out horizontal light, similar to that of blinds for a window.  The colors typically used are dark grey  or dark brown.
Is one color  better than the other?  In my opinion, I feel color is a personal preference.  While both lens colors will reduce light, grey will keep everything its normal color, just darker.  Brown lenses will tend to give everything a slight red hue.   Both lenses will filter light in the visible color spectrum (290-320nm) and UVA and UVB light (320-400nm), the latter being most harmful to the eye and skin. Brown lenses will also filter out "Blue Light'' or High Energy Visible light. (440-490nm).  This may be a bit technical, but  UVA and UVB light exposure is considered a major contributor to cataracts, eyelid cancer and forms of skin cancer.  The High Energy  or Blue Light can damage the retina over time, leading to macular degeneration..


Fun Facts about polarized lenses...


-About 25 years ago or more, polarized lenses were marketed to fishermen as lenses that would let you see over 12 inches below the surface of the water.  It seemed like a miracle, but it simply got rid of the glare on the surface to allow that person to get a clear look into the water.
-While wearing polarized lenses, if you look at an LCD readout, such as a wrist watch or at a gas pump, you'll see only a black spot.  The numbers won't be visible unless you tip your head to the side approximately 35-40 degrees.
-Also, while wearing polarized lenses, you will be able to see "stress" patterns in tempered glass. (Store front windows, car windshields and some glass lenses)
-Well, I hope I've been able to help you choose your next pair of sunglasses.  Make sure you click the follow tab at the top, or even share this with your Facebook friends!

Welcome to June

Summer has arrived, almost overnight. .  After weeks of severe storms and last week in the 50's, Memorial Day Weekend gave us 90 degrees and sunny!  As we go to beaches, ball games, camping, etc...our eyes should be protected with some type of sunwear.  Just as we put sunscreen on our exposed skin to protect it from sunburn and skin cancer, our eyes need the same protection from the sun's UV rays to protect from retinal damage and cataracts.  In the next blog, I will give info on types of sunglass lenses.   I hope everyone has a great summer.

Memorial Day Message

This will be a no optical related blog today.  The Eyeguy feels it's necessary to honor the  U.S. Military members who gave their lives to to protect the freedoms we enjoy today. For those of us who haven't had the privilege to serve, our safety and freedoms are taken for granted.  Think about it that, next you're out with your family, reading a blog,  writing you're opinion about something, or just making a life choice for yourself,   we may not be able to make those choices or do those things without those brave men and women putting their lives on the line for us. . Thanks again to our military.  And for everyone that is celebrating or remembering a loved one, have fun and be safe this weekend!