FRAMES AND LENSES
Newest Technologies in Non-Rimmed Eyewear
A Review of the Materials and Manufacturing Technologies
Currently Available in Rimless Eyewear.
By Jackie OKeefe, LDO
While the exact date of the origin of rimless eyewear
is not clear, it is safe to say that it has been around for centuries,
perhaps as long as 600 years. History indicates that in 1824, a
young Austrian named J.F. Voigtlander marketed rimless glasses in
Vienna. Several years later, the style evolved from a single lens
to two lenses joined by a metal bridge (What Man Devised That
He Might See, Richard Drewry, Jr., MD, eye.utmem.edu/history/glass.html).
As the style developed further, temples became a popular inclusion.
During its long history, rimless eyewear has enjoyed
periods of renewed discovery and popularity. For example, around
the turn of the 20th century, rimless eyewear was a fashionable
item. This continued until the mid-20th century when plastic acetate
frames became the rage. Rimless eyewear was rediscovered in the
later part of the century, and remains a hot item in todays
One of the great attractions of rimless eyewear is
its ever-changing technology. At the turn of the 20th century, rimless
eyewear was a flimsy contraption that used cautiously drilled glass
lenses, and was perched precariously on the wearers nose and
tops of the ears. Mounting materials consisted of steel and nickel
silver for lower-end products. Gold and silver with ornate engraving
was used on the upper end. Styling tended to be conservative with
rounds, ovals, and ovoids as the prime choices. Men and women commonly
wore similar shapes and designs, and variety in mountings was limited.
All that has changed. Today rimless eyewear comes in
a plethora of materials, designs, colors, shapes, and sizes. It
comes with countless options like screwless hinges, compression
fittings, and floating chassis. It uses technologies our grandparents
would have found nearly unbelievable. Heres a look at the
fundamentals of rimless eyewear and the latest technology in this
Makes Eyewear Rimless?
Lets start with what rimless is not
its not a
frame. The word frame means that the eyewire (or eyerim if its
a plastic frame) surrounds the lens like a picture frame surrounds
a photograph or painting. Lenses are inserted into a frame. Thats
why rimless eyewear doesnt have eyewires. Instead, the structure
of a rimless on which the lenses articulate is known as a mounting.
The name mounting comes from the fact that the lenses
are laid on top of or mounted onto the rimless
mounting with some method of attachment like screws and nuts, tension,
There are two fundamental classifications of rimless
mountings, full (also known as three-piece) and semi-rimless. Full
rimless mountings have a bridge and two endpieces that attach to
the lenses. The temples are attached to the endpieces. In a semi-rimless
mounting, a bar or lens arm is fitted behind a portion of the lens
(usually the top portion) onto which the temples are attached. Of
course there are numerous variations on these fundamental themes.
The traditional three-piece rimless has two holes drilled into each
lens although variations of this mounting design abound. Screws,
tension, cement, or other securing methods are used to keep the
lenses in place (see Innovations
in Rimless Mountings). In addition, mountings with only
one hole, or as many as four per lens, can be found.
Semi-rimless eyewear features lenses that are attached either with
screws, hardware, cement, a thin nylon cord, or other systems. A
unique type of semi-rimless known as a Supra has a single arm onto
which the lenses are cemented. Cord-mounted semi-rimless mountings
are popular. In this mounting, the lenses are grooved around their
circumference. This is where a thin nylon monofilament line is placed
to secure them.
its long history, rimless eyewear has enjoyed periods of renewed
discovery and popularity.
Rimway-style mountings feature a bridge with an arm
extending from both sides. These arms are hidden behind the tops
of both lenses and are used for attaching the lenses on the nasal
and temporal sides. They also provide additional support for the
lenses. The temples are attached to endpieces at the end of the
Numont mountings also have an arm across the top of
the mounting, but the unique feature for this product is that the
lenses are attached only at the bridge. In other words, the lenses
are not secured on the temporal side. As a result, the lenses seem
suspended in front of the mounting.
Solutions for High-Powered Rimless Lenses
High MinusUse extended endpieces that help the
mountings front offer the total width the patient needs.
This enables you to use smaller lenses. Round off the lenses
thicker corners by rolling and polishing slightly. Fit the
lenses as closely as possible to the eyes and use a wider
bridge if necessary. Suggest higher index lenses that are
thinner and lighter. The best shapes are round or oval. These
help reduce lens thickness and overall weight. Offer lightweight
mountings like stainless steel and titanium.
High PlusUse smaller eyesizes and avoid unusual
shapes and square corners. Suggest lens shapes that have a
smaller effective diameter (ED). Fit the lenses as close as
possible to the eyes. Make sure the bridge of the mounting
has longer pad arms to accommodate the additional thickness
at the nasal on high-plus lenses. Recommend aspheric front
surface lenses because of their flatter design. Offer lightweight
frames that are strong like titanium and copper beryllium.
Rimless and semi-rimless mountings that use drilled lenses are called
drill mounts. The most popular way to secure drill-mounted lenses
is with screws. To do this, holes are drilled through the lenses,
screws are placed though the holes, fitted into the bridge and endpieces,
then screwed down until secure.
Traditional rimless lenses have two holes per lens,
one on the temporal side, one on the nasal side. Usually the screw
is inserted from the front of the lens and a hex nut is used to
secure the screw from the backside. Others place the screw from
the back side and use a decorative nut on the front. A washer is
often used just under the head of the screw to keep the screw snug
and hold it in place. It also serves to avoid damage around the
More traditional styles sport a bridge and endpieces
that have a flat piece attached which fits snug and flat along the
outer lens edges on the temporal and nasal sides. These flat attachments
are known as collars. The collars prevent the lenses from rotating
or moving when mounted. Other types of mounts use a tongue (a flap
of frame material) that wraps around the front and/or back side
of the lens, covering the area where the screw comes through. A
screw is inserted through the tongue and a hex nut is used to secure
the lens. There are many mountings that use both tongues and collars
to hold their lenses in place.
Some of the most advanced technology in rimless eyewear is in the
endpieces. For example, the traditional hinge has been replaced
with a variety of mechanisms like a ball around which the endpiece
swivels. Another uses a post for rotation of the endpiece.
Another exceptional innovation is the floating temple.
In this technology, premium metals like titanium are made flat and
thin thereby allowing them to be highly flexible. The fronts of
the temples are secured to the lenses and the temples literally
One of the factors that has made rimless eyewear so popular is the
use of premium mounting materials. These materials have led the
way in rimless eyewear innovation because they are feature-rich,
and patients have recognized their benefits and value.
rimless mountings dont confine the ophthalmic professional
or patient, as do rimmed eyewear styles.
Titanium is a prime example. Titanium is a lightweight,
durable, and strong metal that is hypoallergenic and corrosion free.
This makes it an excellent rimless material. In its 100% pure form,
its tough. For those who want durability in a lightweight
mounting, pure titanium is the answer. Beta titanium is an alloy
of titanium composed of 74% titanium, 22% vanadium, and 4% aluminum.
In addition to being lightweight and strong, its flexible.
That means it gives during the stresses of wear, and
also makes the material easy to adjust. Its also hypoallergenic.
Memory titaniums flexibility is a wonder to see. A temple
made from it can literally be twisted around your finger, and then
unraveled to return to its original configuration. Marchons
Flexon is the most notable memory metal.
of titaniums great features is that it can be made very thin
and flexible. Silhouette Optical Ltd.s Mininal Art Collection
is a prime example of how thin and flexible titanium (in this case
beta titanium) can be with its floating temples and ultra-thin front.
Stainless steel is another popular premium mounting
material. Constructed from a combination of nickel and chrome, it
is strong, durable, lightweight, corrosion-free, and hypoallergenic.
Like titanium, it can be made very thin while still maintaining
its structural integrity. This makes it ideal for those minimalist
rimless styles so popular today such as Bollés Valorium,
an ultra-lightweight stainless steel that is ergonomically engineered.
Copper beryllium, magnesium, genium, and vanadium
have also become contributors to the premium mounting material scene
although usually as part of an alloy. Often, these materials offer
the thinness and lightweight of premium metals at a lower cost.
Magnesium, for example, which is used in rimless
styles by Allison Eyewear and Oakley, Inc., is 30% lighter than
titanium and 67% as dense as aluminum. These materials offer lightweight,
durability, strength, and hypoallergenic qualities.
many of todays rimless are made of metal, plastic mountings
are also becoming popular. High-tech polymers like acetate, nylon,
nibrodal, crystalline amide, Grilamid TRLX, Micro-Cristalline Polyamide,
trogamid, ceramic polymers, and synthetic SPX and SPXng (both proprietary
materials from Silhouette Optical Ltd.) are good examples.
Traditional zyl (cellulose acetate) has gone
upscale with premium Italian zyl that is supple and colorful, and
retains the light and comfortable qualities of traditional zyl.
Some of Zyloware Corporations Via Spiga styles have double
laminate colorings handmade from Italian zyl.
Polyamide is made from a blend of nylons and
features durability, reduced weight, and flexibility, and is considered
hypoallergenic. Made by injection molding, it is particularly good
with translucent colors and is highly scratch-resistant.
Silhouettes proprietary SPXng (ng stands
for next generation), is a microcrystalline polyamid
that is extremely flexible and heat resistant. It has a memory to
help it retain its shape but is easy to adjust using minimal heat.
While the base color of the material is clear, when an opaque color
flash is placed over it, the result is luminous incandescent color
hues like green, blue violet, and blush.
Grilamid is a lightweight frame material designed
to be rugged, resilient, highly impact resistant, and comfortable.
Its a good match for rimless eyewear, especially when used
for sunwear. It can take the toughest treatment a patient can give
it and maintain its structural integrity. Its light weight also
makes it an ideal rimless material.
Unlike rimmed eyewear, rimless eyewear is nearly limitless in the
shapes, sizes, and designs it can manifest. From classic round and
octagonal shapes to customized unconventional and unique shapes,
theres more versatility in rimless eyewear than any other
form of eyewear.
Three-piece rimless mountings dont confine the
ophthalmic professional or patient, as do rimmed eyewear styles.
Thats because you can place small, large, or any size lens
between the bridge and endpieces. This creates great flexibility
in the designing process and also allows the ophthalmic professional
to only have to stock one size mounting.
Utilizing three-piece rimless mountings, the ophthalmic
professional can use creativity to achieve any look a patient may
want. For instance, the aviator shape is ideal for a sporty look
while the pillowed rectangle is more casual in design. The more
fashion-forward individual may desire a retro look or shapes with
sharp angles that stand out in any crowd.
Manufacturers have discovered the allure of color in rimless eyewear.
Unlike in years past, todays rimless eyewear uses color as
a fashion statement. Technology has allowed manufacturers to create
a spectrum of colors in finishes from shiny bright to satin and
One of the notable successes in rimless mounting coloring
is with titanium. By anodizing or ionizing the material by subjecting
it to electrical currents, the color is found throughout the component.
This creates the highest level of color stability and does not wear
away or peel off in time. The stunning colors range from pale pastels
to bold and vibrant hues.
Making rimless eyewear unique includes selecting and
combining unique colors toonot just the temples and front,
but the endpieces and screws as well. Some eyewear manufacturers
have even begun producing multi-colored mountings. Other colorful
options are to offer a discreet touch of color by using different
colored screws or going wild with multi-colors. The combinations
are virtually endless. Higher-end frames may even be handpainted
for an exclusive look.
New Options in Lens Materials
Rimless eyewear can be challenging when fabricating and adjusting
the final product. Lenses may chip, flake, or breakespecially
around the mounting hole. Thats why glass lenses, along with
their weight, do not make good options for rimless styles.
While CR-39® was a favored lens material for all
kinds of eyewear for many years, it is no longer considered a good
choice for rimless eyewear. One reason stems from its low index
of refraction. In fact, CR-39 has the lowest index of all plastic
lenses materials, resulting in the thickest lens profile for a given
prescription. In a rimless design, thats exactly what you
dont want. Also, CR-39s impact resistance is inferior
to a number of other plastic lens choices. And since rimless mountings
can be fragile because the lenses are drilled, notched, or somehow
secured without a rim, impact resistance is a big issue.
To respond to these unique challenges, many ophthalmic
professionals are looking for good lens options and many ophthalmic
lens providers are introducing lens materials that they position
as rimless eyewear friendly.
Polycarbonate is very rimless friendly. It is a lightweight, strong,
and incredibly impact-resistant lens material. Polycarbonate is
also a bit soft, which makes it excellent for working with rimless
mountings. It drills easily and wont flake and chip around
the hole like glass or some other plastic lens materials. Polycarbonates
light weight makes it a perfect teammate for ultra-thin rimless
mountings too. Optima, Inc. has even developed a stress-free polycarbonateResolution®.
This lens eliminates birefringencean optical phenomenon referring
to double refraction (commonplace among other polycarbonate products)which
can be created from internal stress.
Another great thing about polycarbonate is that it
is available in nearly every lens style imaginable. That means you
can recommend it to all your patients without having to worry that
the style you ordered may not be produced. Patients and ophthalmic
professionals also appreciate that polycarbonate absorbs 100% of
UVA and UVB radiations. And of course, polycarbonate is a high index
material too (index 1.59), so that lenses made from it will have
a nice, thin profile.
Trivex is another terrific rimless-friendly lens material option.
Brought to the ophthalmic industry by PPG Industries, the lenses
are currently available from HOYA VISION CARE, North America, Younger
Optics, and Thai Polymer Lens Co. HOYA markets Trivex lenses under
the Phoenix brand, and Youngers lens line is Trilogy. Trivexs
impact resistance rivals polycarbonatethe material is strong,
and is even lighter than polycarbonate. In addition, its Abbe value
is higher than polycarbonate, which may help some patients who are
sensitive to color aberration. Trivexs unique production process
eliminates internal stress in the lens. In other words, if you were
to place the lens into a polariscope, you wouldnt see any
pattern or color in the lens (color indicates internal stress).
Trivex takes drilling well and wont flake or
chip during the process. Its 1.53 index makes it a premium option
over CR-39 and it is available in a number of lens styles, including
single vision aspherics and progressives. Trivex also absorbs 100%
UVA and UVB radiations.
Other High-Index Materials
Patients today appreciate the thinness and lightness that high-index
lenses represent, particularly if their higher prescriptions provided
them with just the opposite in the past. And rimless eyewear is
fully complemented by thin and light lenses. Plastic mid-index lenses
are available for moderate prescriptions and products with an index
of 1.60 and higher are available too. Within these materials youll
find a full range of lens styles and lens options.
Some high index materials are well suited for rimless
use. For example, Seiko Optical Products 1.67 lenses are composed
of MR-10 resin. This special resin is ideal for rimless mounts because
it drills/notches well and provides a cleaner edge when polished.
It also can withstand the stress of adjustments. Its 1.67 index
of refraction makes it one of the highest in the plastic lens family.
This means it will provide a thin lens profile and lightweight lenses.
Teaming it with an aspheric design creates the ideal
rimless option for the patient. In fact, many low-powered prescription
wearers now opt for higher index lens materials like MR-10 for their
eyewear due to these benefits.
Enhancing the Look
Rimless eyewear is about a minimalist lookless is more. Hence,
the more the dispenser can do to enhance that look, the greater
the patients satisfaction. Adding an anti-reflective (AR)
coating to rimless lensesmaking the eyewear virtually invisibleis
an obvious, significant add-on. But keep in mind that the patient
will also want lenses that are resistant to smudges or relatively
easy to keep clean. There are a number of lens cleaners on the market
today designed expressly for AR lens maintenance.
For those who actually want to go with a more conspicuous
look, custom lens edge treatments can accentuate the final rimless
eyewear product. Try applying color around the flat edge of the
lenses, or groove the lenses and add color to them. Since rimless
eyewear has a tendency to disappear on the face, tinting the lenses
with a light café tint makes them more noticeable. Gradient
tints are an eye-catcher, too. Light mirrored coatings are also
a good choice, especially if they have a single or multiple colored
Rimless eyewear has come a long way from J.F. Voigtlanders
early designs. Todays rimless eyewear products represent the
best styling, materials, and construction modern technology providesbut
who knows whats next?
Jackie OKeefe is a licensed optician. She is
currently employed at Coastal Vision in Virginia Beach, VA.
Issue Date: July/August
Expiration Date: January
This course has been approved for one hour of continuing
education credit by the American Board of Opticianry (ABO).
Upon completion of this program, the participant should be
- Explain the various types of rimless mountings and how
- List the features and benefits of todays premium
- Identify the lens materials best suited for rimless eyewear
and explain why each is a good choice.
Please consult your state licensing board to assure
that this CE counts toward your requirement for maintaining