2016 benz manual

Intraocular
Lens Materials
& Manufacturing

Technology
2014

Features of the
Universal Blank Platform

Universal Blanks High Modulation Transfer Function

Haptic Disc IOL Manufacturers
Optics

Square Edge

Benz hMTF
Optics

Haptic Outline

Benz Universal Blank

Benz Research and Development is pleased to introduce the addition of Benz
Performance Optics to our Universal Blank platform.

Benz Performance Optics provides complete high quality optical forms (asphericity, toricity, and
others) to the posterior optic surface of the Universal Blank. Each blank is 100% inspected enabling
IOL manufacturers to finish machine the anterior lens surface and haptic to their optical specification
to complete their unique IOL optical system.

Benz Performance Optics is the result of an intensive three year development effort and significant
investment that produced a unique molding process, Optical Replication Technology™ (ORT™).
Benz ORT™ is a combination of processes and materials that creates precision formed ultra stable
molds that enable our proprietary casting process that replicates the mold’s intricate optics precisely
every time. The result is a lens optic with higher resolving power (MTF) than typically found in single
vision aspheric IOL’s machined from blanks of material. The entire IOL product range can now
reach near theoretical maximum optical quality for those manufacturers using Universal Blanks with
Benz Performance Optics. The optical resolution data (MTF) for optics made using our Optical
Replication Technology™ is shown below.

Histogram of HF-2 Universal Blanks MTF

30

Mean 0.6372
StDev 0.01370

25

20

Percent 15

10

5

0 0.48 0.51 0.54 0.57 0.60 0.63 0.66
0.45
MTF



Introduction to Benz IOL Materials & Manufacturing Technology

By Dr. Patrick H. Benz, president

Since entering the IOL materials market in 1998, Benz Research and Development has become the

preeminent supplier of quality high performance materials and state of the art technology to the IOL

industry. The reason for our strong growth is our dedication to excellence in both Quality and Innovation.

Our 26 years experience in producing high quality materials for the soft contact lens industry also provides

a very significant foundation for hydrophilic IOL materials.

Expertise in high purity 2-HEMA monomer production extends over 27 years of continuous development.

Our hydrophilic polymer experience of 22 years is substantial. In conjunction with producing 15 novel

polymer materials, we have 19 US patents and 14 foreign patents. Combining this level of expertise in

developing new materials, it is apparent why we have quickly become the leader in IOL materials and we

continue our innovation with 9 US patents pending and IOL Manufacturing Technologies
16 foreign patents pending. Developed by Benz
Micron run-out Spindle Collets
Our current product line consists of three hydrophilic Optical Blocking
IOL materials (IOL25 Universal Blank, IOL25, BenzFlex Optical Cryo Blocking
26) and two hydrophobic IOL materials (HF-1.2 Universal Peltier Effect Cryo Milling
Blank and HF-2 Universal Blank). All of these materials Automated IOL Micro Drill
are available with our patented, covalently bound, natural
chromophore, Natural Yellow.™ In creating patented, value Integrated Lens Manufacturing (ILM-3),
added materials, we provide our customers opportunities full automation
for significant market differentiation, including increased
value to the surgeon as well as the patient. Fully automated IOL25 Universal Blank
Manufacturing (UBM)
Fully automated Cryo Manufacturing (ILM-C)

Since 1995 Benz Research and Development has committed many man-years of effort to advance

the state-of-the art in lens manufacturing technology. Our efforts have yielded both innovative and

powerful manufacturing technologies for today’s IOL manufacturer. These advances include Optical

Blocking, Laser Blocking, Automated Video Inspection, Optical Cryo Blocking, Automated Laser Profiling

of Aspheric Optics, a fully Integrated Hydrophilic IOL Manufacturing System and our newest Automated

Cryo Manufacturing, all validated to the ISO 13485 standard. Our newest material products are the

HF-1.2 Universal Blank, HF-2 Universal Blank and the IOL25 Universal Blank. These unique products

greatly reduce the manufacturing costs while increasing the precision of IOL manufacture. With our

commitment to R&D, we continue to expand the boundaries of both IOL materials and manufacturing

technology. Developing superior technology to make superior products — this is what Benz Research

and Development is all about.

ZERO TECHNOLOGY & monomer
ULTRAPURE MONOMER
99.9%
2

Most manufacturers would agree that high quality products
start with high quality raw materials. To the IOL manufacturer,
this means the highest quality polymer blanks. For Benz
Research and Development this means starting with the
very highest Quality monomer raw material possible,
period and controlling that quality. Fortunately, we have a
vast amount of expertise in the manufacture of high purity
2-Hydroxyethylmethacrylate (2-HEMA), the primary monomer
component used in hydrophilic acrylic IOL material. In the
mid-1980s we developed a 2-HEMA manufacturing process that
produced 99.5% pure monomer, a bench mark for the soft lens
industry world wide for more than 19 years. Therefore, we have
core expertise in a technology vital to Quality IOL materials.

Calcium Particle Formation

COO- + Ca+2 HPO4-2 +H3O+ CO O - C a +2 H 2P O 4- + H2O

Calcium Phosphate Calcium Phosphate Particle

Methacrylic Acid In The Polymer Matrix

Polymer Matrix Polymer Matrix

Figure 1 3

Six years ago, one of our goals as a company was to develop Zero Technology produces a raw material that is so pure that
an advanced 2-HEMA manufacturing process that produces the methacrylic acid content is difficult to even measure.
raw material monomer with a purity that is consistent with The resulting hydrophilic acrylic IOL polymer has 10 to 20X
the requirements of the IOL industry rather than the soft less acid than even “highest purity” commercial monomer,
lens industry. We call this process Zero Technology. Our Zero plus a much higher total purity, this results in a zero ionicity
Technology Process delivers an ultra pure material with polymer. Zero ionicity IOL material provides a further degree
99.9% purity, the quality expected for a polymer implant that of Quality Assurance by eliminating the possibility of calcium
may be in the eye for more than 40 years. We call our IOL phosphate particles appearing over time in the polymer
monomer, L3 Monomer, for Log 3 or 99.9. matrix, which can lead to opacification, see Figure 1.

This technology advancement makes Benz R&D the only IOL
material supplier that has actual control of its raw material
quality and separates us from our competitors, who continue
to use raw materials manufactured to meet molded soft lens
requirements, not IOL material requirements. We are the only
IOL material supplier that is basic in its 2-HEMA monomer
raw material.

Residuals Comparison

Residuals
1.2

1.0

BENEFITS OF Percent Residuals (%) 0.8
BENZ POLYMERIZATION
0.6
TECHNOLOGY
0.4
4
0.2 BenzFlex 26 Competitor
Figure 2

The reputation of Benz Research and Development as a
manufacturer of very high quality contact lens materials is
well known in the custom contact lens industry. In fact, we
would probably be considered the quality benchmark even
by our competitors. Benz materials are characterized by low
residuals, precise and isotropic expansion, and large batch sizes.
Benz R&D currently makes the highest purity, most consistent
hydrophilic and hydrophobic IOL materials, period. An actual
comparison of the quality resulting from Benz polymerization
technology vs. our competitors polymerization technology
is straightforward. Our BenzFlex 26 consistently has a much
lower residual monomer content (0.5% vs. 1.1%) and a smaller
matrix or pore size (33% smaller) than competitor materials
made from the same monomers (see Figures 2 and 3). Another
example of quality is shown by examining how completely the
UV blocker is covalently bound to the polymer. A substantial
difference between BenzFlex 26 and competitor material
can be seen in Figures 4 and 5. There are several important
reasons for our high quality.

First, our quality starts with ultra high purity raw materials.
The purity of our raw materials is much higher than that
provided as “high purity” by the chemical companies that
currently manufacture 2-HEMA. Our ultra pure, L3 Monomer
significantly reduces batch-to-batch variability and lowers
the residual monomer content of
our hydrophilic IOL materials.

Second, our polymerization process is carried out in virgin
glass tubes, not the plastic molds of competitor materials.
Plastic molds contain many impurities that affect the
polymerization process as well as contaminate the resulting
polymer, sometimes with toxic components not intended for
IOL use. To understand the scope of the contamination from

Relative Diffusion Rate Matrix Size Comparison Competition

1.8 Unbound UV-Blocker residual from alcohol extraction of a hydrophilic
1.6 IOL material (26% water) from Competitor material.
1.4
1.2 Figure 4

1 BenzFlex 26UV
0.8
0.6 No UV-Blocker residual from alcohol extraction of a hydrophilic
0.4 IOL material (26% water) from BenzFlex 26.
0.2
Figure 5
BenzFlex 26 Competitor 5

Figure 3

plastic molds, you need only to look up all the types of
plasticizers, mold release agents, lubricants and antioxidants
commonly found in polypropylene and polyethylene resins.
These same chemical contaminants can be found in competitor
materials. Virgin glass molds eliminate contamination. Benz
has made it a company priority to use virgin glass molds that
cost substantially more, but provide the assurance of polymer
purity that is essential to Benz Quality.

Third, our polymerization process is carried out in a
uniquely designed computer controlled chamber capable of
polymerization with extreme temperature stability. This
polymerization environment, when combined with advanced
formulation technology, ultra pure monomer and inert glass
molds, allows us to make an extremely consistent, isotropic
polymer. The characteristics of the resulting polymer speaks
for itself. The data support our claims that we have the most
complete polymerization under the most controlled conditions,
period. Making Quality claims based on actual data is
consistent with our marketing approach which is one based
on verifiable product characteristics. Hopefully, this approach
will also become an industry standard.

Fourth, since our polymerization process was designed and
developed by Benz, not adapted from another company’s
production process (such as old contact lens blank casting
processes), our polymerization technology is easily scalable
and not labor intensive. This advantage means that we
produce IOL blanks in batch sizes that are appropriate for
our customer’s requirements. Other manufacturers produce
batch sizes that are limited. Our current batch sizes range from
40,000 to 80,000 blanks per batch. Large batches increase
the reliability of supply as well as provide for more efficient
manufacturing because of less batch qualification tests.

THE PRECISION Diameter, Thickness, Parallel and Squareness
GROUND BLANK &
IOL 25 UNIVERSAL BLANK 3.0 –+ 0.010 mm

12.7 +– 0.010 mm or 14.5 –+ 0.010 mm or 16.0 –+ 0.010 mm

6 0.003 mm 0.008 mm MAX

Figure 6

IOL blanks with consistent and precise dimensions directly
benefit your manufacturing process. Benz Research and
Development uses unique high-speed processes for converting
our high purity polymer into a precision dimensioned blank,
Figure 6. We grind blanks automatically to micron tolerances in
diameter and thickness, with optimum squareness and parallel,
using state of the art machinery and statistical process control
to ensure a highly uniform batch. We invested heavily in this
high volume equipment and technology so that we could
process large batches with precision dimensions. Figures 7 and
8 show typical results for diameter and thickness (in microns)
of a batch of Benz IOL 25UV, 0512072I25. A large batch of I-25
Natural Yellow™ is shown in Figure 9.

Precision dimensions facilitate auto-loading processes and
eliminate the need to electronically locate the surface of the
blank before each machining cycle begins on the lathe. This
alone eliminates about 5 seconds from every lathe cycle saving
significant time and money.

Figure 9

The new IOL 25 Universal Blank is a precision molded disk,
100% inspected for visual and optical defects and laser
mounted on a precision polycarbonate mandrel, see Figure 10.

Diameter Distribution for Benz IOL 25UV LOT 05-12-072125 Thickness Distribution for Benz IOL 25UV LOT 05-12-072125

LSL Tag USL LSL Tag
-3.0s +3.0s -3.0s USL

24 36 +3.0s

18 27

12Frequency 18
Frequency

6 9

12.686 12.692 12.697 12.702 12.707 12.712 12.717 2.987 2.992 2.996 3.000 3.005 3.009 3.014

12.689 12.694 12.699 12.704 12.709 12.714 2.990 2.994 2.998 3.003 3.007 3.011

Microns Microns 7
(lot size 63,000 blanks) (lot size 63,000 blanks)

Figure 7 Figure 8

Figure 9 23.878 0.23 Clearance 23.65 A
Figure 10
Edge Height
Provided In Data Table

3° Ø 12.700±0.010

B 0.006 B 0.006
Section C-C 0.006
6 UM Or Better 0.005
Lens Concentricity To Mandrel Shank A

Property Benz IOL BenzFlex IOL 25
Water Content (wt %) 25 26 Universal Blank
Refractive Index @ 589 nm 25
26 25
Dry 20°C 1.507
Hydrated 20°C 1.460 1.509 1.507
Refractive Index @ 546 nm 1.462 1.460
Dry 20°C 1.509
BENZ HYDROPHILIC Hydrated 20°C 1.462 1.510 1.509
IOL MATERIAL Expansion 1.464 1.462
Linear 1.125
8 Radial 1.125 1.125 1.125
Tensile g/mm2 1.125 1.125
Young’s Modulus g/mm2 33
Diameter (mm) 62 95 31
12.7±0.01 92 69
Thickness (mm) 14.5±0.01 12.7±0.01
Table 1 16.0±0.01 14.5±0.01
3.0±0.01 16±0.01
3.0±0.01

Benz Research and Development has been manufacturing
hydrophilic acrylic IOL materials for many years. During this
time, literally tens of millions of IOLs made from Benz materials
have been implanted. Our material’s reputation in the industry
is one of high quality and consistent trouble-free service. The
development of Zero Technology will assure our customers
that Benz will provide the highest purity polymer available for
their implant products for years to come. Benz materials are
made in virgin glass molds free of potential contamination from
plasticizers, mold release agents, lubricants and anti-oxidants.

Benz IOL 25
IOL 25 is our patented hydrophilic material (US Patent No. 6,517,750),
especially effective for small bore injectable IOLs. This copolymer
of 2-Hydroxyethylmethacrylate and 2-Ethoxyethylmethacrylate
has a unique combination of modulus of elasticity and tensile
strength that allow the finished IOL to be drastically deformed
during injection through openings as smaller than 1.6mm and
return to its original shape and optical performance in the most
desirable time frame. This material also has a history of very low
PCO rates across many designs. The physical properties of Benz
IOL 25 are shown in Table 1.

Benz IOL25 Universal Blank
The Universal Blank is the same material molded as a disk and
precision blocked on a disposable precision mandrel. The posterior
aspheric optic is complete with a 70 micron square edge (hydrated).
A finished lens ready to polish or a polish free lens ready to hydrate
require the same manufacturing steps: one rough cut, one fine cut
and one milling pass. Polish ready or polish free is determined by
the equipment used for the machining step. Deblocking the lens is
done mechanically, with only the lens removed. The total cost for
a finished IOL25 hydrophilic lens prior to inspection and packaging
using this method is <US $4.00 (see Global Contact, issue 2, 2013,
article New Methods in Hydrophilic IOL Manufacturing).

Natural Yellow™ is superior to other yellow IOL materials because it protects
the retina without blocking needed blue light. Blue blocking IOLs reduce low light contrast sensitivity

as well as color perception. These capabilities are critically needed for optimum vision of implant
patients, particularly at night. Benz Natural Yellow™ achieves complete natural protection

without loss of contrast sensitivity or color perception. The human retina has already specified the
exact chromophore it needs for energetic light protection through millions of years evolution,
and that is exactly the chromophore we deliver to our customers, in Benz Natural Yellow™.

9

BenzFlex 26 Nature’s Own Light Filter
BenzFlex 26 is a generic material made from Benz IOL 25 Natural Yellow™ and BenzFlex 26 Natural Yellow™
2-Hydroxyethylmethacrylate and Methylmethacrylate. are the first IOL materials to incorporate the same UV-A blocking
This material’s primary components are the same as other and violet light filtering chromophore that is in the human
products available on the market and has similar mechanical crystalline lens. Our approach to UV blockers and violet filters
properties. The main differences are that BenzFlex 26UV is is to use nature’s own solutions to the problem of protecting the
made with Benz Zero Technology ultra pure monomer and our retina from harmful energetic light. The absorption spectrum
superior polymerization technology as well as made in virgin of the chromophore, 2-Hydroxykynureneine (Figure 11) shows
glass molds. There are important quantitative differences that this natural chromophore is an excellent UV-A blocker
resulting from Benz Zero Technology monomer, Benz’s superior with a secondary purpose of filtering (not blocking) violet
Polymerization Technology and virgin glass molds. These light. This and its beta Glucoside derivative are nature’s
advantages are: very low residuals, zero ionicity, a smaller primary protection for UV-A and violet light. We have made
matrix (pore size), more precise expansion characteristics a special monomer (U.S. Patent 7,947,796) containing the
than competitor materials and no contamination from identical chromophore present in the human crystalline lens and
impurities found in plastic molds. The physical properties of covalently incorporated it into our premier IOL materials. We call
BenzFlex 26 UV are shown in Table 1. these proprietary natural light filtering materials “Natural Yellow™”.

Comparison of 3-HydroxyKynurenine in Saline vs. Benz Natural Yellow™ Chromophore The visible transmission spectrum of Benz IOL 25 Natural
Yellow™ material, 1.0 mm thickness is shown in Figure 12
5.0 UV-A Blocking BENZ Natural Yellow™ Chromophore compared to the transmission spectrum of a young human
4.5 3-HydroxyKynurenine in Saline crystalline lens as defined by van de Kraats and van Norren
4.0 (OSA, posted February 7, 2007, doc ID 76626).
3.5 Absorbance
3.0 % Transmission Comparison of a Young Lens, M(LY) vs. Benz IOL 25 Natural Yellow™
2.5 Violet Filtering
2.5 100
1.5 “Improved 90
1.0 Scotopic Vision”
0.5 M(LY)
0.0 340 360 380 400 420 440 460 80

320 Wavelength (nm) BENZ Natural Yellow™ IOL Materials
70
Figure 11 60
50
40
30
20
10

0
340 360 380 400 420 440 460 480 500 520 540 560 580 600 620

Wavelength (nm)
Figure 12

ø13.40 ± 0.15 Anterior Side: Spheric (Rf ) 0.12 (Front Cut Depth)
Lathe Cut to Achieve Desired Power 0.40±0.20
0.070
and Surface Type
R0.04
A
Square Edge Detail
BENZ HF-1.2
HYDROPHOBIC Posterior Side:
IOL MATERIAL Aspheric (Rb)
CT
10 % Transmission
ø6.00 (OZ) 5º
Transmission of HF-1.2 Natural Yellow™ ø6.05 R0.1
A Section A-A
100
90 Figure 14
BENZ Natural Yellow™
80 While the Benz hydrophilic materials offer the ultimate
Young Lens M(LY) in reliability and performance in a highly biocompatible
70 hydrophilic polymer, our HF-1.2 hydrophobic material offers
60 customers a significant additional value added market
50 because of the promotion of hydrophobic materials by the
40 market leaders.
30
20 We have been developing HF-1.2 material for 9 years and as
10 a result of the latest developments, the opening time has
0 been reduced from 60 seconds to 25 seconds. Because of this
300 340 380 420 460 500 540 580 620 improvement, HF-1 is now called HF-1.2.
Wavelength (nm)
This material has many advantageous characteristics resulting
Figure 13 in a high performance IOL:
• Low chromatic aberration, Abbe number 49
• Very low glistenings (well below clinical threshold)
• Opening time approximately 25 seconds at 25°C
• Mechanical properties similar to IOL 25UV

The Glistening behavior of hydrophobic acrylic rubbers
is well known and has been present ever since the first
products were introduced in the early 1990’s. One of the
most popular hydrophobic IOL materials is the acrylic co-
polymer: 2-Phenylethylacrylate/2-Phenylethylmethacrylate,
the material of the market leading IOL. Recent clinical
reports on the extent of the glistenings of market leading
products and their clinical significance provide marketing
opportunities for new hydrophobic IOL products, such as
Benz HF-1.2.

We have studied extensively the relationship of glistenings
to the manufacturing process parameters in developing the
current process for Benz HF-1.2. We have also adopted the
Trattler Severity Index as a Quality Assurance procedure for
each batch of material. The Severity Index for HF-1.2 batches
has been followed for months submerged in saline

11

Figure 15 Figure 16

and does not change from the first 24 hours submerged in easily verified before producing a custom optic on the
saline. The average Severity Index of 85 batches HF-1.2 is anterior surface. Custom lens powers less than the universal
compared below to the severity index of the market leading blank powers are made by simply machining the front.
IOL material, see Table 2. All one piece designs can easily be manufactured using
the Benz HF-1.2 Natural Yellow™ Universal Blank. Figure
Obviously, there is a clear difference with respect to 14 shows the dimensions of the blank and the amount of
glistenings for these two materials. The reasons are not material available for producing a custom anterior surface.
completely known, but obvious differences in the two Manufacturing is as simple as cryogenic machining of the
materials are the formula components and likely differences front surface using the Benz cryogenic insert and milling
in the polymerization processes. The superior quality of Benz of the haptic. Two manufacturing steps to a finished
HF-1.2 with respect to glistenings is apparent. hydrophobic IOL, Figures 14 and 15.

Benz HF-1.2 Natural Yellow™ Universal Blank is the same Material Glistening Severity Index
polymer composition as the original HF-1 with the addition of
the Benz Natural Yellow™ UV-A blocking and Violet Filtering HF-1.21) Mean Std. Dev Minimum Maximum
monomer (US Patent 7,947,796). Benz Natural Yellow™ SA60, SN602) 718 14 699 749
gives HF-1.2 the same light transmission characteristics as 8,589 327
a young human crystalline lens. The transmission spectrum 9,442 46,361
of HF-1.2 Natural Yellow™ is shown in Figure 13, compared
to a young lens as described by van de Kraats and van Table 2
Norren (OSA, posted Feb. 7 2007, doc ID 76626). HF-1.2
Natural Yellow™ Universal blank has been processed using 1) Data from Benz Research and Development QA Dept.
a special technique to enhance its unfolding characteristics. 2) Aaron Waite, Nathan Faulkner, and Randall J. Olson. Glistenings in the Single-Piece Hydrophobic,
HF-1.2 Natural Yellow™ is made using ultra high purity Acrylic Intraocular Lenses. J Ophthalmol 2007; 144:143-144
monomer and a state of the art polymerization process to
give you a high performance hydrophobic material with Property Benz HF-1.2
the ultimate in reliability. The design of the HF-1.2 Natural Water Natural Yellow
Yellow™ Universal Blank is intended to allow an ease of Tg °C Universal Blank
manufacturing for many Hydrophobic IOL designs. The
posterior side of the blank contains a finished spherical optic <4
and a “square edge”.
3.6
The diopter powers currently available are 7.5, 10, 12.5, 15,
17.5, 20, 22.5, 25, 27.5 and 30 D. By providing both optical Refractive Index @ 589 1.485
surfaces finished, the optical quality of the part can be 20°C 1.483
35°C
1.487
Refractive Index @ 546 1.485
20°C 288 g/mm2
35°C 560 g/mm2
Tensile
Modulus 49
Abbe Number

Table 3

Benz Natural Yellow™ Chromophore

5.0 UV-A Blocking
4.5
BENZ UV-A Absorbance 4.0 BENZ Natural Yellow™ Chromophore
BLOCKING MATERIALS 3.5 Violet Filtering
3.0
12 2.5 340 360 380 400 420 440 460
2.5
1.5 Wavelength (nm)
1.0
0.5
0.0

320

Figure 17

Benz UV-A blocking materials fall into two categories:
Natural Yellow™ and clear UV. Natural Yellow™ is a unique
UV-A blocking and violet light filtering naturally occurring
chromophore patented by Benz, US Patent 7,947,796. This
exact chromophore is in every human liquid crystalline
lens. Nature’s intent for this chromophore is readily seen by
examining its UV-Visible absorption spectrum shown in Figure 17.

As you can see, nature designed its final protection of the
retina to be a strong and broad UV-A absorbing chromophore
with a maximum absorption centered at 370 nm, extending
with lesser absorption to 440 nm, through the violet region of
the visible spectrum. Although most UV light is absorbed by
the cornea*, the remainder is intended to be absorbed by this
chromophore present in the human lens. This is what nature
has specified for retina protection and therefore, Natural
Yellow™ IOL materials provide the most appropriate UV
protection for a lens replacement material.

*L. Kolozsvari, A. Nogradi, B. Hopp and Z Bor, “UV Absorbance of the Human
Cornea in the 240 t 400 nm Range,” IOVS, July 2002, Vol. 43, No 7.

IOL 25 UV-Vis% Transmission IOL 25 UVX™ Extreme Photostability
% Transmission
100 100
13
90 90
Benz IOL 25 UV Benz IOL 25 UVX™ Day 0

80 80
Benz IOL 25 UVX™ Benz IOL 25 UVX™ Day 20

70 70 Benz IOL 25 UVX™ Day 40
using ISO 11979-5-2006 (Annex D)
60
60
50
50
40
40
30
30
20
20
10
10
0
0
200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450
200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450
Wavelength (nm)
Wavelength (nm)
Figure 18 Figure 19

Clear UV-A blocking materials are IOL materials that block Because of these factors and in order to protect our customers
UV-A light only, therefore these materials appear clear, from unnecessary and time consuming clinical tests, we have
without any yellowish tint. Up until recently, clear UV-A recently developed a new IOL UV-A blocker with Extreme
blocking has been accomplished primarily with two classes Photostability and very high UV-A absorption, Benz UVX™
of chromophores, Benzophenones and Benzotriazoles. Both (patent pending). This new covalently bound UV-A blocker
of these chromophores are in wide use in the IOL industry. achieves 5% transmission at 370 nm with only 0.15 wt%
Our approach to clear UV-A blocking, until now, has been to added to the polymer. This small amount of covalently
provide 10% transmission at 360 nm using a Benzophenone bound chromophore means no change in water content,
chromophore at a concentration (approx. 0.2%) sufficient refractive index, tensile strength or modulus. The transmission
for 20 year protection under natural reflected UV-A light spectrum of Benz IOL 25 UVX™ and Benz IOL 25 UV is shown
conditions after the light has passed through the cornea in Figure 18. The results of 20 year photostability using ISO
and the pupil. The current ISO Photostability Test fails to 11979-5-2006 (Annex D) test conditions is shown in Figure 19.
fully account for UV-A absorption by the cornea or account The small amount of UVX™ required to meet both the 10% at
for the pupil size in bright sunlight. This results in the use of 370 nm transmission requirement and 20 year photostability
unnaturally intense UV-A light in the ISO photostability test, requirement means that no properties of IOL 25, BenzFlex or HF-1.2
resulting in an unnaturally severe photostability requirement are altered EXCEPT UV blocking. UVX passes all polymer safety
for UV blockers. In addition, there is a current proposal tests, is non-extractable and covalently bound to the polymer.
to create a new ISO standard for IOL UV blocking of 10% Therefore, no clinical testing is required. Benz UVX™ is
transmission at 370 nm. This standard would require much, available in all Benz IOL materials.
much higher levels of Benzophenone, resulting in water content
and refractive index changes to the IOL material, potentially
resulting in new clinical testing of many current IOL products.

MACHINING

RECOMMENDATIONS

14

Figure 20

Benz hydrophilic IOL materials can be easily machined to give
excellent surface quality by using the proper machining conditions
and sharp, proper geometry diamond tools. Conditions and tools
are very important and must be controlled for consistent results.
Hydrophilic acrylic IOL materials are glassy polymers and machine
similar to contact lens plastics. Tables 4, 5 and 6 show a
summary of tool and machining parameter recommendations.
Using larger tool diameter, greater depth of cut or faster feed
rate than recommended can reduce the effective expansion of
the material because of induced stress into plastic. To ensure the
highest yield, we recommend that each manufacturer verify the
radial and linear expansion values given for each lot using their
own manufacturing and testing procedures.

Benz Hydrophobic materials require cryogenic conditions for optimum
machining. Cryogenic temperatures can be easily achieved using
commercially available freezing devices that can be attached to the
spindle of your existing lathes. Blanks are mounted on a special
mandrel using moisture (see Figure 20). The mandrel is cooled to
at least -20°C using a vortex freeze station. Once the mandrel is
cooled, it is placed in the lathe collet that is fitted with a cryogenic
unit. The surface of the blank must be maintained at -20°C or below.
The blow-off air must also be adjusted to the same temperature
and dry (<-50°F dew point). Use the cutting parameters in Tables 7
and 8.

Our newest product, the IOL 25 Universal blank is provided as a
molded disk, similar to the HF-1 universal blank and precision
blocked on a disposable bar coded mandrel. The product features
a hollow mandrel for convenient in-process QC of the optics.
The haptic disk has a 5° angulation or 0° angulation (see
Figure 21).

15

Figure 21 Polish Free Manufactured Dry Lens

Lathe Tools Polish Free Manufacturing Conditions

Tool Radius Top Rake Relief Lathe Tools*
Rough Cut Tool 0.40 mm 0°/-2.5° 15°
Finish Cut Tool 0.30 mm 0°/-2.5° 15° Tool Radius
Table 4 Rough Cut Tool .20 mm
Finish Cut Tool .20 mm

Benz IOL25 UV and BenzFlex 26 *controlled wave tools required

Rough Cut Lathe Parameters Lathe Parameter*
Speed (rpm) Fine Cut
Tool Feed (mm/min) 9,500 Speed (rpm) Rough Fine
Depth of Cut (mm) 10,000 Speed (rpm) 26 Tool Feed (mm/min) 12000 11500
Blank Surface Temp (C°) 89 Tool Feed (mm/min) 0.12 Depth of Cut (mm)
0.35 Depth of Cut 60 25
<-20° .06 .04
<-20° Blank Surface Temp (C°)

Table 5 *Opto Form 80 Lathe

IOL25 Universal Blank Milling Parameters
• Equipment, Optomill 363
Lathe & Milling Parameters • 0.400mm x 1.2mm Diamond Endmill (Wiediam Diamonds)
• 1st & 2nd Cut Feed, 88mm/min, 80,000 rpm
Rough Fine Milling • 3rd Cut Feed, 91mm/min, 90,000 rpm
1st pass • 1st Cut Stops 0.050mm ( approximately 0.250mm depth)
Speed (rpm) 9,000 8,000
Tool Feed (mm/min) 88.9 50.8 120,000 shy of breaking through to wax
Depth of Cut (mm) .06 .04 101.6 • 2nd Cut Goes 0.050mm ( approximately 0.350mm total)
Table 6
past the lens into the wax
HF-1.2 Natural Yellow™ • 3rd Cut Backs off 0.030mm depth, with a radial cut of

Lathe Parameters 0.030 – 0.040mm
• Cycle time, 150 seconds
Rough Cut Fine Cut

Speed (rpm) 9,000 Speed (rpm) 8,000
48.26
Tool Feed (mm/min) 88.9 Tool Feed (mm/min) 0.07
<-20°
Depth of Cut (mm) 0.13 Depth of Cut Environmental
Blank Surface Temp (C°) <-20° Blank Surface Temp (C°) 70 ± 3°F (21 ± 2 °C)
35 ± 3% RH
Table 7

HF-1.2 Natural Yellow™

Milling Parameters

Rough Cut Fine Cut

Speed (rpm) 160,000 Speed (rpm) 160,000
63.5
Tool Feed (mm/min) 76.2 Tool Feed (mm/min) <-20°

Blank Surface Temp (C°) <-20° Blank Surface Temp (C°)

Table 8

Isotonic Saline

Borate Buffer pH 7.2; 295 mOs

NaCl 8.01 grams

H3BO3 2.47 grams

Na2B4O7 • 10H2O 0.14 grams

HYDRATION OF The weights for the buffered saline
BENZ HYDROPHILIC formula is based on a 1 liter solution.
The borate solution shows excellent
MATERIALS performance through the sterilization
process (autoclaving) and leaves the
16
lenses free of residue.

Table 9

Hydration Recommendations for Hydrophilic
Intraocular Lenses (IOLs):
Hydration of IOLs made from hydrophilic materials is a crucial
step in IOL manufacture because it serves two functions.
1. Hydration transforms the plastic into a soft hydrogel.
2. Hydration cleans the lens by removing residuals from the lens.

During the hydration process one must follow sterile controls
and keep bioburden levels low to ensure no biological growth
on the lenses while hydrating. This requires using sterile
technique to make the hydration saline solution and in handling
and cleaning the lenses.

Hydrate the lenses in Borate Buffer pH 7.2 isotonic saline
(see Table 9) or similar buffered saline solution. The procedure
recommended for hydration is as follows:
a) Place the dry, polished IOLs in perforated vials immersed

in saline solution (a minimum of 10 ml volume per IOL is
recommended) at room temperature for 24 hours with stirring.
b) Replace the saline solution with fresh saline solution
(a minimum of 10-ml volume per IOL is recommended) and
continue to hydrate for an additional 24 hour with stirring.
c) After the 48 hour hydration period, the lenses should be
removed from the saline and cleaned with a lens cleaning
solution (such as Bausch & Lomb lens cleaner) or a basic
lab detergent (such as a solution of Tergazyme and water).
Use sterile technique. Once hydration and cleaning is
complete, the lens power is determined to confirm Diopter
and MTF using a measurement method consistent with ISO
standards. After measurement of each lens it is recleaned
with lens cleaning solution and rinsed thoroughly to remove
residual lens cleaner.
d) Lenses are now ready for packaging and sterilization.
Use sterile technique.

17



BENZ MANUFACTURING TECHNOLOGY

ACHIEVING
COLLET TO COLLET

PRECISION

20

Figure 24

Precision and productivity have always been key ingredients
for the success of lens manufacturing, both contact lenses
and IOLs. Today a modern CNC lathe can produce highly
complex geometries with ultra smooth surfaces. These lathes
provide excellent precision for one step, but once the part is
removed from the collet, precision is lost. Therefore, the lathe’s
precision has not necessarily resulted in ultra precision lenses
because the precision of front side machining is lost during
each of two discrete mechanical steps: blocking and second
side machining. Significant precision is lost during these steps
as the part moves from collet-to-collet. Before the total lens
manufacturing process can become very precise, collet-to-
collet position repeatability must be improved. We have solved
the problem of collet-to-collet precision by using technology
specifically developed to address the two components of collet
precision: run-out and position.

Ø0.4995±0.0001 Reading # Total Indicated Run (mm) 21
[Ø12.687mm±0.0025mm] 1 0.0036
2 0.0038
3 0.0039
4 0.0036
5 0.0036
6 0.0041
7 0.0034
8 0.0025
9 0.0036
10 0.0029
0.0035
Average 0.0005
SD

Figure 25 Table 10

Collet run-out occurs because the collet’s center of rotation Using this precision position dead-length system and precision
does not match the lathe spindle’s center of rotation. This dimension blanks, it is no longer necessary to measure the
mismatch of rotational symmetry typically produces a collet position of the surface before beginning first side machining.
run-out of 20-40 microns. This loss in precision is compounded This saves time on every lathe machining cycle. Figure 24
through blocking and second side machining (3 more collets). shows a picture of the Benz mandrel with a precision blank
The Benz spindle/collet assembly eliminates this inaccuracy. attached and the same mandrel and the centering ring used for
In the Benz spindle the mismatch of the collet to its spindle’s wax mounting the blank into the mandrel.
spin center is eliminated by precision lapping the collet cone
into the spindle shaft until reaching the desired spindle/collet The Benz spindle with precision lapped dead-length collet,
run-out. A portion of the exhaust air from the spindle is also precision mandrels and blank mounting centering rings are all
redirected through the collet to prevent swarf from altering available as technology products from Benz R&D.
the tolerance of the cone-collet surface. The Repeatability of
Total Indicated Run-out (TIR) of a Benz Precision Steel mandrel
during 10 repeated collet loads on a 4-Axis Lathe, using the
Benz spindle/collet Assembly is shown in Table 10.

The second component of collet-to-collet precision is
repeatability of position. We have solved this by designing
a precision dead-length collet and a precision steel mandrel
(the blank is mounted with wax onto the mandrel’s
surface for first side machining), see Figure 24 and 25.

Calibration Values (X And Y Axis) for a
Typical Set-Up Sequence on the Optical Blocker

Note the standard deviation of total position (max-min) repeatability.

Part # Center (mm) Y1 (mm) X2 (mm) Y2 (mm) X1 (mm) Max-Min

1 0.158 0.135 0.135 0.131 0.131 0.004

OPTICAL BLOCKING & 2 0.153 0.145 0.147 0.146 0.142 0.005
OPTICAL CRYO BLOCKING
3 0.155 0.145 0.146 0.141 0.141 0.005
22
4 0.155 0.143 0.147 0.142 0.140 0.007

5 0.152 0.142 0.145 0.141 0.141 0.004

Average 0.155 0.142 0.144 0.140 0.139 0.005

SD 0.002 0.004 0.005 0.006 0.005 0.001
Table 11

Optical blocking was invented and patented worldwide by
Benz Research and Development in 1994. Since building
our first machine in 1994, we have greatly expanded the
functions and overall capabilities of the Optical Blocker for
manufacturing contact lenses and IOLs. The Benz Optical
Blocker today represents the only commercially available
blocking interface between first side and second side
machining that achieves accuracy and precision comparable
to the lathes currently used in manufacturing. The Benz
Optical Blocker is designed and built to deliver unequaled
accuracy and precision through years of trouble free use.
Our original blocker is still in use at Benz R&D.

The new Laser Blocking feature reduces cycle time and
provides in-process QC of aspheric optics.

The Benz Optical Blocker provides many manufacturing
advantages and can be used as a stand-alone machine
operated manually, by robot or fully integrated into an
automated system, Benz Integrated Lens Manufacturing.

Video Haptic Inspection

Figure 26

Optical Cryo Blocker 23
Benz Optical Cryo Blocker
Optical Blocking eliminates the following common manufacturing Our newest Optical Blocking CNC device is the Optical Cryo
problems associated with blocking: Prism error, centration Blocker. In order to achieve <10 micron concentric accuracy
variations, and center thickness variations. when blocking the HF-1.2 and HF-2 Universal blanks Benz has
developed the fully automated Benz Cryo Blocker. High MTF
Increased yield with improved quality are the obvious benefits lenses require concentric accuracy when blocking the first
of Optical Blocking. Additional benefits to your manufacturing side optic. The Optical Cryo Blocker can feed 2 MLC’s in an
competitiveness that may not be obvious are: integrated cell (ILM-C). The blocking sequence is shown below.
• Automatically provides micron accurate radius measurement
• Measures of spherical radius as well as major, minor axis of Dispensing Blocking Water

toric lenses with a permanent record of measurements Freeze Blocking the Universal Blank
• Laser profiles of aspheric optics
• Automatically rejects base curves that do not meet tolerance Finished Blocked Part Ready for Machining

you set
• Automatically calibrates your lathes for radius and sphere to

tolerances that you set and provides a real time process control
record of lathe calibrations

Specific Features of the Optical Blocker
1. Measures radius of curvature with + 2 microns accuracy
2. Measures both major and minor cylinder radii of toric lenses

with + 2 micron accuracy
3. Positions apex of concave and convex lenses with + 2 microns

in X, Y and Z
4. Concentric blocking – average max – min variations in edge

thickness of 5 microns, see Table 11
5. Cylinder alignment of toric lenses on second side mandrel to

better than 0.5° accuracy
6. Constant center thickness of lenses + 2 microns
7. Automatically calibrates lathes for radius and sphere
8. Provides“dead-length”apexblocking–constantdistancebetween

second side mandrel base and apex of mounted first side lens
9. Includes full automatic, semi-automatic and manual mode

of operation
10.Laser profiles of aspheric optics

ILM-C

CRYO MANUFACTURING

OF HF-1.2 & HF-2

24

Automated Cryo Manufacturing has been made possible by
the development of the Benz Optical Cryo Blocker. As the
starting point, the HF-1.2 and HF-2 Universal Blanks have
eliminated first side machining of hydrophobic IOLs. The
next step in development of Integrated Lens Manufacturing
for hydrophobic IOLs is integrating the Optical Cryo Blocker
with Cryo MLC’s. ILM-C is shown on the opposite page. In
ILM-C, 100 part trays of HF-1.2 or HF-2 Universal Blanks are
the raw material input. These are fully inspected and bar
coded trays of specific diopter parts. Approximately 100
microns of material is removed in two passes and the haptic
is milled.

The blocker cycle is <60 sec from picking the Universal Blank
from its tray and blocking on a cryo mandrel and cooled to
-28°C. ILM-C, with its robotic part handling, keeps 2-MLC’s
working at full capacity. When the MLC finishes cutting the
lens the cryo mandrel is moved to an automatic station
that warms the mandrel, removes the finished lens to a
special container, and cleans the mandrel to start another
manufacturing cycle.

The productivity of ILM-C is >140,000 finished lenses per year
when operated 16 hours/day, 250 days/year. One operator is
required per shift. Guaranteed yield is 96%.

ILM CRYO 25
Cryo Blocker

Mill / Lathe
Combo 1

Robot Cleaning
Station

Mill / Lathe
Combo 2

1. Order Entry &
Customer ID

10. Packaging & 2. Lens Design
Labeling

INTEGRATED 9. Hydration & Automation 3. Blank
LENS MANUFACTURING or Inspection Software Mounting
(Robotic)
(ILM) 8. Polishing & Database
4. 1st Side Optics
26 Lathing & Milling

(Robotic)

7. 2nd Side Optics 6. Deblocking 5. Optical Blocking
Lathing & Cleaning (Robotic)
(Robotic) (Robotic)

Figure 27

Integrated Lens Manufacturing (ILM-3) is a lens manufacturing
process developed and refined over the past 13 years.
Benz Research and Development has spent millions of
dollars developing the component systems and automation
technology used in ILM. In ILM each lens manufactured has
a discrete identity. This identity is defined by order number
and the bar code numbers associated with each portion of the
manufacturing process:
• First side manufacturing and blocking;
• Second side manufacturing, polishing and hydration
• Inspection, packaging and labeling

All data associated with each lens, including the order, and
all manufacturing data from each step is saved in the Oracle 10
database of ILM-3.

The Benz Automation Program is a large C program that
coordinates all automation steps and storage of all data
associated with each order including machining parameters
created by the front end Design Program for use in each
manufacturing step. The Benz Automation Program also
coordinates the activities and movements of the tray feed
system, blank mounting, lathes, optical blocker, drill, deblocker
and robots. Figure 27 illustrates the flow of information and
instructions including all robot moves and bar code reads
coordinated by the automation program.

ILM-3 Systems Operations:
The ILM system has been designed for both function and flexibility. ILM-3 also allows
the system manager to easily add or delete equipment under its control while remaining in
continuous operation. The process manager can select each machine mode, thereby
optimizing operation time and allowing for other functions like maintenance, or diamond change,
that takes a single machine off line while the remaining equipment remains in automation.
Adding cells and rearranging equipment within cells is easy through the secure operator interface.
There is no limit to the size of the total ILM-3 system imposed by the Benz Automation Program.

27

ILM is designed for robotic handling of parts. Manual ILM-3 Manufacturing Sequence
part handling can be substituted for robots, but with a The first step to starting ILM-3 is loading clean mandrels in
substantial loss in productivity. ILM operated with robots will trays into the Tray Feed System, making sure that the
require approximately 1/8 of the manpower of a traditional vibratory hopper is full of blanks and the wax applicators on
manufacturing process. Also, all lathe calibration for radius the Automatic Blank Mounting Machine and Optical Blocker
and sphere are automatically performed using ILM. This are full. The next step is to calibrate the lathes Y-Axis to the
further reduces total manpower because all lathe calibration Optical Blocker Z-Axis and verify the concentricity of the
is done manually in a traditional manufacturing process. Blocker. This will take 1 hour or less. Now IOL lenses can be
ordered in any combination from singles to hundreds at the
ILM utilizes the following manufacturing technology in a fully Order Entry Terminal. Finished lenses on their second side
integrated system: mandrels and used first side mandrels are returned to their
• The Benz precision spindle/collet assembly with Benz mandrels trays in the Tray Feed System. Each tray of mandrels and
• The Benz Optical Blocker with high speed Laser Blocking lenses can be conveniently handled and cleaned using the trays
• The Benz IOL Drill with the Benz Solvent Cleaning System.
• The Benz Tray Feed System
• The Benz Automatic Blank Mounting System
• The Benz Automatic Deblocking System
• The Benz Solvent Cleaning System
• The Benz ILM Automation Program utilizing an Oracle 10

database
• Custom ILM part handling robot effectors
• Re-calculation of the second side radius for every part based

on the actual measured first side radius
• Real-time re-calibration of all lathes for radius and sphere
• Design front end program for spherical and toric lens

designs that is accessible for further customization by each
manufacturer.
• Windows-based operator interface for all manufacturing
operations including Order-Entry, Maintenance, Quality
Control, Inspection, and Auto Calibration
• Automatic laser profiling of aspheric surfaces
• Automatic video inspection of haptic milling

ILM-3

28

Auto-Lathe Calibration
One of the unique features of the ILM-3 is auto-lathe
calibration. This feature allows for automatic adjustments
to be made to all the lathes in this system for radius and
sphere. During initial start-up, two calibration parts are
machined on each lathe, one to calibrate and a second to
verify both the radius and the sphere. During the production
day, calibration parts are automatically run on the lathes in
the system at an interval chosen by the operator. Production
parts can also be used for calibration. Lathes are maintained
to tighter operational tolerances using the precision of the
Optical Blocker inspection and the auto-calibration feature.
All first side lathes are 100% monitored because all first sides
are optically inspected before being blocked. An example of
a DAC ALM calibration record and its optical blocker radius
measurements are shown in Figure 28.

Productivity of ILM
The productivity of ILM has been extensively studied at BRD.
We have used a 3-cell system in full production for almost
eight years. With this level of experience, Benz Research and
Development will guarantee the productivity of your ILM-3 system.

Production Results for Lathe 002
Production Error Mean = 1.8 µm SD + 1.2 µm

60.0 µm RO Error (microns) Production
40.0 µm Calibration
20.0 µm Measurement

0.0 µm 13:00 13:30 14:00 14:30 15:00 15:30 29
-20.0 µm
-40.0 µm
-60.0 µm

Figure 28

ILM-3

Optical DAC MLC
Blocker
Blank Mounting,
Deblocking and

Cleaning

Transfer
Track

DAC MLC

DAC MLC Tray Feed
System

DAC MLC

ILM PERFORMANCE Measured Final Power (Dpt) ILM Performance
VALIDATION
Confidence (R2) = 0.9993
30
32
30
28
26
24
22
20
18
16
14
12
10
8
6

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Figure 29

ILM Performance
To determine the true accuracy of ILM we have made many
tests utilizing groups of 120 identical lenses and measured
each lens both dry and wet on a Rotlex IOLA. We also calculated
what the wet power should be from the measured dry power
and compared this to the actual measured wet power. The
results of over 200 of these tests are shown in Figure 29.

As the data clearly show, the accuracy and precision of ILM is
extremely high, especially when you consider that half of the
measured standard deviation of sphere measurements is due
to the lens analyzer error. The excellent accuracy and precision
of ILM drastically reduces the amount of inspections needed to
insure the power and MTF of production lenses.

Validation of ILM
As with any automated system, process validation is the key to
ensuring product consistency and quality. This is particularly
important with hydrophilic IOLs because the material requires
both accuracy in dry manufacturing and consistent expansion
during hydration to hit the desired power and dimensional
targets. Benz IOL material is perfectly suited for ILM because of
its precision expansion properties. To validate the ILM system
we selected a symmetrically biconvex spherical lens, C-loop
design, manufactured from one specific lot of hydrophilic IOL
material (Benz-IOL 25), see Table 12.

Manufacturing Parameters for Lenses from ILM Calculations

Data Input Radius (mm) ILM Calculation OZ Diameter (mm)
Final Lens Diopter 7.80 Center Thickness (mm) 5.370
11.03 5.370
+28.0 18.44 1.269 5.370
+20.0 0.967
+12.0 0.686
Table 12

Comparison of 1st Side Optics Radius and Before Polishing After Polishing
Semi-Finished IOL to Target Parameters 20 D

Target 11.030 mm Target 0.967 mm Target 0.270 mm Target 5.370 mm Power MTF Power MTF
19.8 0.45 19.8 0.59
1st Side Dry Lathe - Cut IOL 19.8 0.60 19.8 0.57
19.8 0.58 19.8 0.56
Barcode # Measured Radius Center Thickness Haptic Thickness OZ Diameter 19.8 0.53 19.8 0.53
19.8 0.55 19.8 0.59
6269 11.0316 0.971 0.272 5.378 19.8 0.63 19.8 0.58
6615 11.0338 19.8 0.56 19.8 0.58
5775 11.0371 0.971 0.271 5.374 19.8 0.54 19.8 0.58
7414 11.0344 19.8 0.63 19.8 0.56
6702 11.0341 0.966 0.276 5.379 19.8 0.57 19.8 0.54
7455 11.0371
7481 11.0308 0.968 0.270 5.373
6659 11.0276
6538 11.0341 0.965 0.268 5.376
5541 11.0318
6415 11.0328 0.964 0.272 5.369
6380 11.0298
AVERAGE 11.0329 0.970 0.275 5.373
SD 0.0028
0.974 0.274 5.374

0.967 0.274 5.369 19.8 0.56 19.8 0.59
19.8 0.51 19.8 0.59
0.964 0.268 5.380 19.8 0.58 19.8 0.59
19.8 0.54 19.8 0.59
0.956 0.274 5.373 19.80 0.60 19.80 0.60
0.05 0.046 0.02 0.03
0.956 0.271 5.376
Table 14
0.966 0.2721 5.3745 AVG 31
SD
0.0056 0.0026 0.0035

Table 13

Sample lenses were randomly selected from production Finally, Table 15 shows a summary of the evaluation data
orders consisting of 120 lenses of each power, manufactured demonstrating the precision and accuracy of the Benz ILM
using the ILM system. system. These validation results indicate that when using the
ILM system to manufacture IOLs, QA time can be significantly
Following lathing the 1st side optics and milling the haptics, reduced because ILM can be validated for statistical sampling
each part is precision blocked, in the optical blocker, after and analysis for power. ILM results in higher yields, optimum
the optics have been examined and centered and the radius target hitting, reduced parameter inspection and significantly
measured. This radius data is used to re-calculate the target higher productivity. Validation of the ILM system, per ISO-
radius on the 2nd side optic to ensure optimum target 13485 standards, is part of the package when purchasing a
hitting. Second side optic is then lathe-cut and the dry IOL complete ILM system from Benz Research and Development.
de-blocked and cleaned. A sample size consisting of 60 lenses ILM performance is guaranteed.
was selected at random from each Diopter batch. Out of this
sample, a set of thirty (30) lenses were hydrated directly after Summary of the Data for All Lenses
lathing (before dry polishing) and a second set of thirty (30)
lenses were polished using the Benz proprietary dry-polish IOL Power (Dpt) +28.0 +20.0 +12.0 +28.0 +20.0 +12.0
process followed by hydration. While in the dry-state, we
measured each lens OZ diameter, center thickness and haptic Target Measured
thickness. Table 13 shows the measured radius of 12 randomly Dimension (mm)
selected 20 D lenses from a 120-part order along with the data
for CT, haptic thickness and optic diameter. Center Thickness 1.269 0.967 0.686 1.262 0.964 0.678
0.007 0.007
Using an IOLA model # V2.2.34 from Rotlex, the Diopter SD 0.020 0.020 0.020 0.006 5.374 5.375
power and MTF of the hydrated lenses were determined for 0.004 0.005
both sets, before and after polishing. MTF offers a display of OZ Diameter 5.370 5.370 5.370 5.372
fringe patterns that give visual information on imperfections 19.8 12.0
in the IOL and can be indicative of defects in a manufacturing SD 0.020 0.020 0.020 0.004 0.03 0.06
process. Table 14 shows the data for 14 lenses randomly 19.8 11.9
selected from the set of +20.00 Diopter lenses. Hydrated Power (dpt) 0.02 0.05

Before Dry Polishing 28.0 20.0 12.0 27.8 0.54 0.58
0.05 0.04
SD 0.25 0.25 0.25 0.04 0.55 0.56
0.03 0.02
After Dry Polishing 28.0 20.0 12.0 27.8

SD 0.25 0.25 0.25 0.04

MTF

Before Dry Polishing 0.43 min 0.43 min 0.43 min 0.46

SD 0.03

After Dry Polishing 0.43 min 0.43 min 0.43 min 0.48

SD 0.02

Table 15

Direct Cost of Intraocular Lenses Manufactured
in the ILM-3 System

Hours – Estimated Daily

Item Quantities Cost Description Expense

Number of BLANKS 1125 $1.50 98.5% yield $1,688.00
Per Day 22.5 hrs

Average Production 24hr $15.00 Benefits@ x1.2 $432.00
Operator Cost x 24

ILM-3 Average Consumable 22.5 hrs $80.00 Including $80.00

32 Costs Polishing

Subtotal – Cost Per Day $2,200.00

Add Daily Overhead Cost at 25% $550.00

Total Direct Cost Per Day $2,750.00

Daily Output @ 98.5%, 1108 lenses

Direct Cost Per Lens $2.48

Table 16

The ILM-3 Quality System
The Benz Integrated Lens Manufacturing Process was
developed with quality products in mind and is part of the
overall Quality Management System of Benz Research and
Development. ILM-3 is compliant with the stringent quality
system requirements of ISO 13485, which embraces the
principals of good manufacturing practices and quality
system regulations. These quality standards and regulations
satisfy the specific quality management requirements for the
development and manufacture of medical devices.

As a result, ILM-3 is a fully documented, controlled and
validated process that delivers a product of consistently high
quality. ILM-3 is a turn-key process. Currently ILM-3 is fully
validated for automated manufacture of biconvex IOLs from +8
to +35 D. Extensions to this range or optics other than spherical
biconvex such as torics, require only additional validation
tests to be performed not a change in ILM-3. ILM-3 is also fully
validated for statistical verification of power and MTF. Because
of the validated accuracy and repeatability of ILM, 100%
inspection of IOLs for power is not required, only statistical
verification in accordance with your specific ANSI AQL Standard.

Profitability of ILM-3
Using Table 16 you can determine the appropriate gross profit
potential of an ILM production cell shown in Figure 30.
The following assumptions have been made:
• A 24 hours/day operation (1 hour set-up and calibration,

22.5 hours of production)
• Use 4 DAC MLCs
• Average yields of 98.5% through machining. Yields are

guaranteed and based on our experience manufacturing
semi-finished lenses.

Environmental Requirements BENZ RESEARCH & DEVELOPMENT
Registered to ISO-13485 : 2003
Temperature 21ºC + 2 File No. A7130

RH 37% + 5 at 21ºC 33

Air 90 psi at -60C Dew Point

2-Lathe System, 12 CFM

4-Lathe System, 20 CFM

Electrical 2-Lathe System, 6 KVA

UPS 4-Lathe System, 10 KAV

208-240V single phase

Per Day Profitability for An ILM-3 Four Lathe System increasingly larger systems. To increase capacity starting with
Based on the above example, productivity is 1108 machined a 2-lathe ILM-3 system, you simply add 2 more lathes.
lenses per day at a direct cost of US $2.48 per IOL 25UV lens. To increase capacity starting with a full 4 lathe ILM-3 system
The estimated profitability [(Productivity x ASP) – Direct Cost = you would need a new ILM-3 System, but with only 2-lathes
Profit] using an average sale price (ASP) per unit of US $20.00 to start and no new software, only a faster server.
would be about $19,060 per day.
ILM-3 offers expandability without the headaches of expensive
ILM-3 Expandability training, turnover, hourly rate growth and an ever expanding
The ILM-3 software provides for unlimited expansion of work force. ILM-3 keeps your cost of goods under control for
production cells. No additional software is required to operate years to come.

Space Requirements ILM-3

283˝ [7.200m]

224˝ [5.700m]

Figure 30



BENZ UNIVERSAL BLANK MANUFACTURING (UBM)

UNIVERSAL BLANK

MANUFACTURING (UBM)

36

Figure 31

Manufacturing hydrophilic IOLs from Benz IOL25 Universal Blanks
The IOL 25 Universal Blank is a precision molded IOL blank
containing a haptic disk and two precision molded optical
surfaces, optically blocked onto a low run-out disposable mandrel
containing a 2D barcode. The advanced features of Integrated
Lens Manufacturing (ILM) are built into each Universal Blank,
providing the manufacturer a means to achieve the same
production efficiency and manufacturing precision as ILM.
Drawings of the IOL 25 Universal Blank and Mandrel are shown
in Figures 9 and 10. Front and side views of actual Universal
Blanks shown in Figures 31 and 32.

As you can see from the above images, the Universal Blank
looks very much like a part in ILM production that is about to be
second side finished cut and milled, that is because it has been
produced with all of the technology of ILM and more, including
extremely accurate optical blocking. Also, the data contained in
ILM for an individual part at this stage of production is provided
with each shipment of Universal Blanks, including the addition of
a full optic inspection that is not available from ILM or any other
IOL manufacturing process for that matter. The IOL 25 Universal
Blank represents a unique assembly of highly advantageous
manufacturing technologies in a ready to use form that is produced
by Benz Research and Development’s Quality Manufacturing
Team in the high volumes demanded by our customers to meet
the ever growing IOL market. Custom optics are also available
with appropriate minimum volume contracts.

The Benz Universal Blank requires a minimum of capital
investment to achieve a new level of precision manufacturing
and only a modest additional investment to achieve fully
automated precision machining. The minimum requirement for
high precision machining is a very low TIR dead stop collet/spindle
of 0.002 mm or better. An example of such a spindle is shown in
Figure 33.

37

Figure 32 Figure 33

Figure 34 Figure 35

High precision, Fully Automated Manufacturing can be Figure 35 shows 5 trays of Universal Blanks being loaded into
achieved using a DAC MLC with Benz Autoloader and data the autoloader. Please, read our article in Global Contact on
acquisition software. Benz Research and Development Automated Manufacturing using the IOL 25 Universal Blank.
provides a fully validated Universal Blank Manufacturing
(UBM) System utilizing the DAC MLC. We will provide all
documentation for EN13485 validation and certification
plus a production deblocking and cleaning system (100
parts per cycle) at no charge. Also, with the UBM system,
polishing time is approximately 14 hours using the Benz Dry
Polishing Process. Polish free lenses can be made from the
Universal Blank using the Optoform 80 Lathe (see Global
Contact, issue 2, 2013, article New Methods in Hydrophilic
IOL Manufacturing).The Universal Blanks are shipped in foil
packaging in ready to use barcoded trays of 100 parts, see
Figure 34.



Benz Research and Development has implemented a major program towards renewable energy and conservation. Beginning
in the summer of 2007, Benz Research and Development installed a 25,000 watt solar panel array and began a comprehensive
program to examine energy use. This has resulted in several important energy conservation projects that have reduced our
electrical power demand by 50,000 watts. Our current energy conservation projects include 250 KW of gas turbine power
combined with a high efficiency heat recovery system to provide 1,080,000 BTUs of air conditioning via LiBr absorption
chillers and 400,000 BTUs of process hot water. The overall efficiency of our Combined-Heat-and-Power system (CCHP) is
approximately 70%, which has helped us to further trim our electrical power demand by 100,000 watts. benzrd.com