IntraocularLens Materials

& ManufacturingTechnology

2013

THE NEXT GENERATION HYDROPHOBIC MATERIAL HF-2

Preloaded MICS

HF-2 is the newest material from Benz, and has been designed as part of a two hydrophobic

material strategy. HF-2 is designed for MICS injectors and fast opening times of under 10

seconds. HF-1.2 is designed for 2.2 – 2.4 mm injectors and has an opening time of 25 seconds

(HF-1.2 is discussed in detail on pages 10 – 11). Both materials are available in the Universal

Blank format that greatly reduces the cost of manufacturing hydrophobic IOLs.

HF-2 is intended for high value markets that require preloaded MICS capable designs and fast

opening times. Lenses made from HF-2 are dry sterilized in plasma or ethylene oxide and do

not require wet packaging to achieve both non-stickiness and very low glistenings that are

well below the clinical threshold. HF-2 is a unique hydrophobic acrylic polymer that achieves

these very advantageous characteristics while maintaining an Abbey number of 47, becoming

the fi rst MICS capable hydrophobic material with low chromatic aberration.

HF-2 Natural Yellow IOLs have the same Abbey number (47) AND the same transmission

spectrum as the young Human Crystalline Lens. The spectral characteristics of HF-2 Natural

Yellow IOLs provide the cataract patient with visual characteristics that are the closest yet

to the young Human Crystalline Lens.

Cryo Blocking

HF-2 Universal Blanks can be Cryo Blocked by hand using a Benz Table Top freezing device and cryo mandrel or Blocked Optically using the Benz Optical Cryo Blocker. Hand blocking achieves a concentric accuracy of approximately 40 microns. Optical Blocking achieves a concentric accuracy of <10 microns. Benz Blocking Water mixture is used for blocking in both methods.

Cryo Milling

HF-2 can be cryo milled using either the Benz Peltier Cryo Mill or a MLC (mill/lathe combo), DAC or Optoform, fi tted with a Benz Vortex cooling device. The use of an MLC is a one stop process of machining and milling. Using a separate Cryo Mill requires cleaning the Universal Blank after machining and re-freezing it on the Peltier plate of the mill. The milling parameters are the same as HF-1.2, p. 15.

Cryo Machining

Machining the Cryo Blocked HF-2 Universal blank is a two pass process carried out at a -28°C surface temperature with -31°C blow off air. The machining parameters are the same as HF-1.2, P 15.

Sterilization

HF-2 lenses can be Ethylene Oxide sterilized as is typical for dry sterilized hydrophobic IOLs. Recently, Benz has successfully sterilized both HF-1.2 and HF-2 by H2O2 Plasma. This new method is safe, effi cient and has a convenient with cycle time of approximately 50 minutes.

Water Content; Wt% < 5% < 5%

UV Cut Off (1mm disc) < 2% @ 400nm < 10% @ 370nm

Residuals; % < 0.15% < 0.15%

Optic Purity >99.98% >99.98%

Severity Index < 750 < 750

Refractive Index at 589nm At 20˚C 1.519 At 20˚C 1.519 (Nominal Value) At 35˚C 1.514 At 35˚C 1.514

Refractive Index at 546nm At 20˚C 1.520 At 20˚C 1.520 (Nominal Value) At 35˚C 1.515 At 35˚C 1.515

ABBE Number 47 47

Tg 10˚C 10˚C

Opening Time @ 25˚C* 10 sec 10 sec

*Opening Times based on a +27 D C-Loop with a 6.0 mm optic using a 2.2 mm Medicel Accuject Injector

Dimension Specifications for HF-2 Universal blanks are on page 10.

Benz HF-2 Natural Yellow™

HF-2 SPECIFIFATIONS

Benz HF-2 UVX™

Introduction to Benz IOL Materials & Manufacturing TechnologyBy 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 signifi cant 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

16 foreign patents pending.

Our current product line consists of three hydrophilic

IOL materials (IOL25 Universal Blank, IOL25, BenzFlex

26) and two hydrophobic IOL materials (HF-1.2 Universal

Blank and HF-2 Universal Blank). All of these materials

are available with our patented, covalently bound, natural

chromophore, Natural Yellow.™ In creating patented, value

added materials, we provide our customers opportunities

for signifi cant market differentiation, including increased

value to the surgeon as well as the patient.

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 Profi ling

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.

IOL Manufacturing Technologies Developed by Benz

Micron run-out Spindle Collets

Optical Blocking

Optical Cryo Blocking

Peltier Effect Cryo Milling

Automated IOL Micro Drill

Integrated Lens Manufacturing (ILM-3), full automation

Fully automated IOL25 Universal Blank Manufacturing (UBM)

Fully automated Cryo Manufacturing (ILM-C)

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.

Six years ago, one of our goals as a company was to develop

an advanced 2-HEMA manufacturing process that produces

raw material monomer with a purity that is consistent with

the requirements of the IOL industry rather than the soft

lens industry. We call this process Zero Technology. Our Zero

Technology Process delivers an ultra pure material with

99.9% purity, the quality expected for a polymer implant that

may be in the eye for more than 40 years. We call our IOL

monomer, L3 Monomer, for Log 3 or 99.9.

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.

Zero Technology produces a raw material that is so pure that

the methacrylic acid content is diffi cult to even measure.

The resulting hydrophilic acrylic IOL polymer has 10 to 20X

less acid than even “highest purity” commercial monomer,

plus a much higher total purity, this results in a zero ionicity

polymer. Zero ionicity IOL material provides a further degree

of Quality Assurance by eliminating the possibility of calcium

phosphate particles appearing over time in the polymer

matrix, which can lead to opacifi cation, see Figure 1.

Z E R O T E C H N O LO GY &

U LT R A P U R E M O N O M E R

2 3

monomer99.9%

Figure 1

Calcium Particle Formation

Calcium Phosphate ParticleCalcium Phosphate

Methacrylic Acid In The Polymer Matrix

Polymer Matrix Polymer Matrix

COO- + Ca+2 HPO4-2 +H3O+ COO- Ca+2 H2PO4

- + H2O

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

signifi cantly 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

B E N E F I T S O F

B E N Z P O LY M E R I Z AT I O N

T E C H N O LO GY

4

Figure 2

1.2

1.0

0.8

0.6

0.4

0.2

Residuals Comparison

CompetitorBenzFlex 26

Residuals

Perc

ent R

esid

uals

(%)

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 verifi able 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 effi cient

manufacturing because of less batch qualifi cation tests.

5

Figure 3

1.8

1.6

1.4

1.2

1

0.8

0.6

0.4

0.2

Matrix Size Comparison

CompetitorBenzFlex 26

Rela

tive

Diff

usio

n Ra

te

Figure 4

Competition

Unbound UV-Blocker residual from alcohol extraction of a hydrophilicIOL material (26% water) from Competitor material.

Figure 5

BenzFlex 26UV

No UV-Blocker residual from alcohol extraction of a hydrophilicIOL material (26% water) from BenzFlex 26.

23.878Edge Height

Provided In Data Table

6 UM Or BetterLens Concentricity To Mandrel Shank

0.23 Clearance

Ø 12.700±0.010

23.65 A

A

Section C-C

3°

0.006 0.006

0.006

0.005

B

B

THE PRECISION

GROUND BLANK &

IOL 25 UNIVERSAL BLANK

6 7

IOL blanks with consistent and precise dimensions directly

benefi t 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

signifi cant time and money.

Figure 9 Figure 10

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.

Figure 6

Diameter, Thickness, Parallel and Squareness

3.0 0.010 mm+–

12.7 0.010 mm or 14.5 0.010 mm or 16.0 0.010 mm

0.003 mm 0.008 mm MAX

+–

+–

+–

Figure 7

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

12.68612.689 12.694 12.699 12.704 12.709 12.714

USLLSL

24

18

12

6

+3.0s-3.0s

Tag

12.692 12.697 12.702 12.707 12.712 12.717

Microns(lot size 63,000 blanks)

Freq

uenc

y

Figure 8

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

2.9872.990 2.994 2.998 3.003 3.007 3.011

USLLSL

36

27

18

9

+3.0s-3.0s

Tag

2.992 2.996 3.000 3.005 3.009 3.014

Freq

uenc

y

Microns(lot size 63,000 blanks)

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 fi nished 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 fi nished lens ready to polish or a polish free lens ready to hydrate

require the same manufacturing steps: one rough cut, one fi ne 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 fi nished 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).

BenzFlex 26

BenzFlex 26 is a generic material made from

2-Hydroxyethylmethacrylate and Methylmethacrylate.

This material’s primary components are the same as other

products available on the market and has similar mechanical

properties. The main differences are that BenzFlex 26UV is

made with Benz Zero Technology ultra pure monomer and our

superior polymerization technology as well as made in virgin

glass molds. There are important quantitative differences

resulting from Benz Zero Technology monomer, Benz’s superior

Polymerization Technology and virgin glass molds. These

advantages are: very low residuals, zero ionicity, a smaller

matrix (pore size), more precise expansion characteristics

than competitor materials and no contamination from

impurities found in plastic molds. The physical properties of

BenzFlex 26 UV are shown in Table 1.

Nature’s Own Light Filter

Benz IOL 25 Natural Yellow™ and BenzFlex 26 Natural Yellow™

are the fi rst IOL materials to incorporate the same UV-A blocking

and violet light fi ltering chromophore that is in the human

crystalline lens. Our approach to UV blockers and violet fi lters

is to use nature’s own solutions to the problem of protecting the

retina from harmful energetic light. The absorption spectrum

of the chromophore, 2-Hydroxykynureneine (Figure 11) shows

that this natural chromophore is an excellent UV-A blocker

with a secondary purpose of fi ltering (not blocking) violet

light. This and its beta Glucoside derivative are nature’s

primary protection for UV-A and violet light. We have made

a special monomer (U.S. Patent 7,947,796) containing the

identical chromophore present in the human crystalline lens and

covalently incorporated it into our premier IOL materials. We call

these proprietary natural light fi ltering materials “Natural Yellow™”.

The visible transmission spectrum of Benz IOL 25 Natural

Yellow™ material, 1.0 mm thickness is shown in Figure 12

compared to the transmission spectrum of a young human

crystalline lens as defi ned by van de Kraats and van Norren

(OSA, posted February 7, 2007, doc ID 76626).

B E N Z H Y D R O P H I L I C

I O L M AT E R I A L

8 9

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 specifi ed 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™.

Table 1

Water Content (wt %) 25 26 25

Refractive Index @ 589 nm

Dry 20°C 1.507 1.509 1.507

Hydrated 20°C 1.460 1.462 1.460

Refractive Index @ 546 nm

Dry 20°C 1.509 1.510 1.509

Hydrated 20°C 1.462 1.464 1.462

Expansion

Linear 1.125 1.125 1.125

Radial 1.125 1.125 1.125

Tensile g/mm2 33 95 31

Young’s Modulus g/mm2 62 92 69

Diameter (mm) 12.7±0.01 12.7±0.01

14.5±0.01 14.5±0.01

16.0±0.01 16±0.01

Thickness (mm) 3.0±0.01 3.0±0.01

Benz IOL BenzFlex IOL 25Property 25 26 Universal Blank

M(LY)

BENZ Natural Yellow™ IOL Materials

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

Figure 12

Comparison of a Young Lens, M(LY) vs. Benz IOL 25 Natural Yellow™

100

Wavelength (nm)

% T

ran

smis

sio

n

90

80

70

60

50

40

30

20

10

0

Figure 11

5.0

320 340 360 380 400 420 440 460

Wavelength (nm)

Ab

sorb

ance

4.5

4.0

3.5

3.0

2.5

2.5

1.5

1.0

0.5

0.0

Comparison of 3-HydroxyKynurenine in Saline vs. Benz Natural Yellow™ Chromophore

UV-A Blocking

Violet Filtering

“ImprovedScotopic Vision”

3-HydroxyKynurenine in Saline

BENZ Natural Yellow™ Chromophore

While the Benz hydrophilic materials offer the ultimate

in reliability and performance in a highly biocompatible

hydrophilic polymer, our HF-1.2 hydrophobic material offers

customers a signifi cant additional value added market

because of the promotion of hydrophobic materials by the

market leaders.

We have been developing HF-1.2 material for 9 years and as

a result of the latest developments, the opening time has

been reduced from 60 seconds to 25 seconds. Because of this

improvement, HF-1 is now called HF-1.2.

This material has many advantageous characteristics resulting

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 fi rst

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 signifi cance 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

B E N Z H F -1 . 2

H Y D R O P H O B I C

I O L M AT E R I A L

10 11

and does not change from the fi rst 24 hours submerged in

saline. The average Severity Index of 85 batches HF-1.2 is

compared below to the severity index of the market leading

IOL material, see Table 2.

Obviously, there is a clear difference with respect to

glistenings for these two materials. The reasons are not

completely known, but obvious differences in the two

materials are the formula components and likely differences

in the polymerization processes. The superior quality of Benz

HF-1.2 with respect to glistenings is apparent.

Benz HF-1.2 Natural Yellow™ Universal Blank is the same

polymer composition as the original HF-1 with the addition of

the Benz Natural Yellow™ UV-A blocking and Violet Filtering

monomer (US Patent 7,947,796). Benz Natural Yellow™

gives HF-1.2 the same light transmission characteristics as

a young human crystalline lens. The transmission spectrum

of HF-1.2 Natural Yellow™ is shown in Figure 13, compared

to a young lens as described by van de Kraats and van

Norren (OSA, posted Feb. 7 2007, doc ID 76626). HF-1.2

Natural Yellow™ Universal blank has been processed using

a special technique to enhance its unfolding characteristics.

HF-1.2 Natural Yellow™ is made using ultra high purity

monomer and a state of the art polymerization process to

give you a high performance hydrophobic material with

the ultimate in reliability. The design of the HF-1.2 Natural

Yellow™ Universal Blank is intended to allow an ease of

manufacturing for many Hydrophobic IOL designs. The

posterior side of the blank contains a fi nished spherical optic

and a “square edge”.

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

surfaces fi nished, the optical quality of the part can be

easily verifi ed before producing a custom optic on the

anterior surface. Custom lens powers less than the universal

blank powers are made by simply machining the front.

All one piece designs can easily be manufactured using

the Benz HF-1.2 Natural Yellow™ Universal Blank. Figure

14 shows the dimensions of the blank and the amount of

material available for producing a custom anterior surface.

Manufacturing is as simple as cryogenic machining of the

front surface using the Benz cryogenic insert and milling

of the haptic. Two manufacturing steps to a fi nished

hydrophobic IOL, Figures 14 and 15.

Figure 16Figure 15

1) Data from Benz Research and Development QA Dept.2) Aaron Waite, Nathan Faulkner, and Randall J. Olson. Glistenings in the Single-Piece Hydrophobic, Acrylic Intraocular Lenses. J Ophthalmol 2007; 144:143-144

Figure 13

Mean Std. Dev Minimum Maximum

HF-1.21) 718 14 699 749

SA60, SN602) 8,589 9,442 327 46,361

Material Glistening Severity Index

Table 2

Benz HF-1.2 Natural Yellow Property Universal Blank

Water <4

Tg °C 3.6

Refractive Index @ 589

20°C 1.485

35°C 1.483

Refractive Index @ 546

20°C 1.487

35°C 1.485

Tensile 288 g/mm2

Modulus 560 g/mm2

Abbe Number 49

Table 3

Figure 14

Anterior Side: Spheric (Rf )Lathe Cut to Achieve Desired Power

and Surface Type 0.12 (Front Cut Depth)

Square Edge Detail

ø13.40 ± 0.15

ø6.0

5

ø6.0

0 ( O

Z)

5º

A

A

R0.1

Section A-A

R0.04

CT

0.40±0.20

Posterior Side:Aspheric (Rb)

0.070

% T

rans

mis

sion

100

90

80

70

60

50

40

30

20

10

0

Wavelength (nm)

300 340 380 420 460 500 540 580 620

Transmission of HF-1.2 Natural Yellow™

BENZ Natural Yellow™

Young Lens M(LY)

12 13

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 fi ltering 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 fi nal 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 specifi ed 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.

Clear UV-A blocking materials are IOL materials that block

UV-A light only, therefore these materials appear clear,

without any yellowish tint. Up until recently, clear UV-A

blocking has been accomplished primarily with two classes

of chromophores, Benzophenones and Benzotriazoles. Both

of these chromophores are in wide use in the IOL industry.

Our approach to clear UV-A blocking, until now, has been to

provide 10% transmission at 360 nm using a Benzophenone

chromophore at a concentration (approx. 0.2%) suffi cient

for 20 year protection under natural refl ected UV-A light

conditions after the light has passed through the cornea

and the pupil. The current ISO Photostability Test fails to

fully account for UV-A absorption by the cornea or account

for the pupil size in bright sunlight. This results in the use of

unnaturally intense UV-A light in the ISO photostability test,

resulting in an unnaturally severe photostability requirement

for UV blockers. In addition, there is a current proposal

to create a new ISO standard for IOL UV blocking of 10%

transmission at 370 nm. This standard would require much,

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.

Because of these factors and in order to protect our customers

from unnecessary and time consuming clinical tests, we have

recently developed a new IOL UV-A blocker with Extreme

Photostability and very high UV-A absorption, Benz UVX™

(patent pending). This new covalently bound UV-A blocker

achieves 5% transmission at 370 nm with only 0.15 wt%

added to the polymer. This small amount of covalently

bound chromophore means no change in water content,

refractive index, tensile strength or modulus. The transmission

spectrum of Benz IOL 25 UVX™ and Benz IOL 25 UV is shown

in Figure 18. The results of 20 year photostability using ISO

11979-5-2006 (Annex D) test conditions is shown in Figure 19.

The small amount of UVX™ required to meet both the 10% at

370 nm transmission requirement and 20 year photostability

requirement means that no properties of IOL 25, BenzFlex or HF-1.2

are altered EXCEPT UV blocking. UVX passes all polymer safety

tests, is non-extractable and covalently bound to the polymer.

Therefore, no clinical testing is required. Benz UVX™ is

available in all Benz IOL materials.

% T

rans

mis

sion

100

90

80

70

60

50

40

30

20

10

0

Wavelength (nm)

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

IOL 25 UV-Vis

Benz IOL 25 UV

Benz IOL 25 UVX™

Figure 18

% T

rans

mis

sion

100

90

80

70

60

50

40

30

20

10

0

Wavelength (nm)

IOL 25 UVX™ Extreme Photostability

Benz IOL 25 UVX™ Day 0

Benz IOL 25 UVX™ Day 20

Benz IOL 25 UVX™ Day 40using ISO 11979-5-2006 (Annex D)

Figure 19

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

B E N Z U V-A

B LO C K I N G M AT E R I A L S

Figure 17

5.0

320 340 360 380 400 420 440 460

Wavelength (nm)

Ab

sorb

ance

4.5

4.0

3.5

3.0

2.5

2.5

1.5

1.0

0.5

0.0

Benz Natural Yellow™ Chromophore

UV-A Blocking

Violet Filtering

BENZ Natural Yellow™ Chromophore

M AC H I N I N G

R E C O M M E N DAT I O N S

14 15

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 fi tted 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).

Polish Free Manufactured Dry LensFigure 21Figure 20

Tool Radius Top Rake Relief

Rough Cut Tool 0.40 mm 0°/-2.5° 15°

Finish Cut Tool 0.30 mm 0°/-2.5° 15°

Table 4

Lathe Tools

Lathe Parameters

Rough Cut Fine Cut

Speed (rpm) 10,000 Speed (rpm) 9,500

Tool Feed (mm/min) 89 Tool Feed (mm/min) 26

Depth of Cut (mm) 0.35 Depth of Cut 0.12

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

Table 5

Benz IOL25 UV and BenzFlex 26

Table 6

Rough Fine Milling Milling 1st pass 2nd pass

Speed (rpm) 9,000 7,500 50,000 55,000

Tool Feed (mm/min) 33 15 80 88

Depth of Cut (mm) .06 .04 0.10

IOL 25 Universal Blank

Lathe & Milling Parameters

Lathe Parameters

Rough Cut Fine Cut

Speed (rpm) 9,000 Speed (rpm) 9,000

Tool Feed (mm/min) 18 Tool Feed (mm/min) 10

Depth of Cut (mm) 0.13 Depth of Cut 0.07

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

Table 7

HF-1.2 Natural Yellow™

Milling Parameters

Rough Cut Fine Cut

Speed (rpm) 50,000 Speed (rpm) 50,000

Tool Feed (mm/min) 30 Tool Feed (mm/min) 45

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

Table 8

HF-1.2 Natural Yellow™

Tool Radius

Rough Cut Tool .20 mm

Finish Cut Tool .20 mm

Lathe Tools*

*controlled wave tools required

Rough Fine

Speed (rpm) 12000 11500

Tool Feed (mm/min) 60 25

Depth of Cut (mm) .06 .04

Lathe Parameter*

*Opto Form 80 Lathe

Milling Parameters

• Equipment, Optomill 363

• 0.400mm x 1.2mm Diamond Endmill (Wiediam Diamonds)

• 1st & 2nd Cut Feed, 88mm/min, 80,000 rpm

• 3rd Cut Feed, 91mm/min, 90,000 rpm

• 1st Cut Stops 0.050mm ( approximately 0.250mm depth)

shy of breaking through to wax

• 2nd Cut Goes 0.050mm ( approximately 0.350mm total)

past the lens into the wax

• 3rd Cut Backs off 0.030mm depth, with a radial cut of

0.030 – 0.040mm

• Cycle time, 150 seconds

Environmental

70 ± 3°F (21 ± 2 °C)

35 ± 3% RH

Polish Free Manufacturing Conditions

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 confi rm 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.

H Y D R AT I O N O F

B E N Z H Y D R O P H I L I C

M AT E R I A L S

16 17

The weights for the buffered saline

formula is based on a 1 liter solution.

The borate solution shows excellent

performance through the sterilization

process (autoclaving) and leaves the

lenses free of residue.

Table 9

Borate Buffer pH 7.2; 295 mOs

NaCl 8.01 grams

H3BO3 2.47 grams

Na2B4O7 • 10H2O 0.14 grams

Isotonic Saline

B E N Z M A N U FAC T U R I N G T E C H N O LO GY

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. Signifi cant 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

specifi cally developed to address the two components of collet

precision: run-out and position.

Collet run-out occurs because the collet’s center of rotation

does not match the lathe spindle’s center of rotation. This

mismatch of rotational symmetry typically produces a collet

run-out of 20-40 microns. This loss in precision is compounded

through blocking and second side machining (3 more collets).

The Benz spindle/collet assembly eliminates this inaccuracy.

In the Benz spindle the mismatch of the collet to its spindle’s

spin center is eliminated by precision lapping the collet cone

into the spindle shaft until reaching the desired spindle/collet

run-out. A portion of the exhaust air from the spindle is also

redirected through the collet to prevent swarf from altering

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 fi rst side machining), see Figure 24 and 25.

Using this precision position dead-length system and precision

dimension blanks, it is no longer necessary to measure the

position of the surface before beginning fi rst side machining.

This saves time on every lathe machining cycle. Figure 24

shows a picture of the Benz mandrel with a precision blank

attached and the same mandrel and the centering ring used for

wax mounting the blank into the mandrel.

The Benz spindle with precision lapped dead-length collet,

precision mandrels and blank mounting centering rings are all

available as technology products from Benz R&D.

AC H I E V I N G

C O L L E T TO C O L L E T

P R E C I S I O N

20 21

Figure 24

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

Average 0.0035

SD 0.0005

Table 10

Reading # Total Indicated Run (mm)

Figure 25

Ø0.4995±0.0001

[Ø12.687mm±0.0025mm]

Optical blocking was invented and patented worldwide by

Benz Research and Development in 1994. Since building

our fi rst 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 fi rst 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.

Optical Blocking eliminates the following common manufacturing

problems associated with blocking: Prism error, centration

variations, and center thickness variations.

Increased yield with improved quality are the obvious benefi ts

of Optical Blocking. Additional benefi ts to your manufacturing

competitiveness that may not be obvious are:

• Automatically provides micron accurate radius measurement

• Measures of spherical radius as well as major, minor axis of

toric lenses with a permanent record of measurements

• Laser profi les of aspheric optics

• Automatically rejects base curves that do not meet tolerance

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

Specifi c 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” apex blocking – constant distance between

second side mandrel base and apex of mounted fi rst side lens

9. Includes full automatic, semi-automatic and manual mode

of operation

10. Laser profi les of aspheric optics

Benz Optical Cryo Blocker

Our newest Optical Blocking CNC device is the Optical Cryo

Blocker. In order to achieve <10 micron concentric accuracy

when blocking the HF-1.2 and HF-2 Universal blanks Benz has

developed the fully automated Benz Cryo Blocker. High MTF

lenses require concentric accuracy when blocking the fi rst

side optic. The Optical Cryo Blocker can feed 2 MLC’s in an

integrated cell (ILM-C). The blocking sequence is shown below.

OPTICAL BLOCKING &

OPTICAL CRYO BLOCKING

22 23

Figure 26

Video Haptic Inspection

Table 11

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

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

2 0.153 0.145 0.147 0.146 0.142 0.005

3 0.155 0.145 0.146 0.141 0.141 0.005

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

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

Dispensing Blocking Water

Freeze Blocking the Universal Blank

Finished Blocked Part Ready for Machining

Optical Cryo Blocker

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 fi rst 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 specifi c 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 fi nishes cutting the

lens the cryo mandrel is moved to an automatic station

that warms the mandrel, removes the fi nished lens to a

special container, and cleans the mandrel to start another

manufacturing cycle.

The productivity of ILM-C is >140,000 fi nished lenses per year

when operated 16 hours/day, 250 days/year. One operator is

required per shift. Guaranteed yield is 96%.

ILM-C

CRYO MANUFACTURING

OF HF-1.2 & HF-2

24 25

Cryo Blocker

ILM CRYO

Mill / LatheCombo 1

Mill / LatheCombo 2

CleaningStation

Robot

Integrated Lens Manufacturing (ILM-3) is a lens manufacturing

process developed and refi ned 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 defi ned 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 fl ow of information and

instructions including all robot moves and bar code reads

coordinated by the automation program.

ILM is designed for robotic handling of parts. Manual

part handling can be substituted for robots, but with a

substantial loss in productivity. ILM operated with robots will

require approximately 1/8 of the manpower of a traditional

manufacturing process. Also, all lathe calibration for radius

and sphere are automatically performed using ILM. This

further reduces total manpower because all lathe calibration

is done manually in a traditional manufacturing process.

ILM utilizes the following manufacturing technology in a fully

integrated system:

• The Benz precision spindle/collet assembly with Benz mandrels

• The Benz Optical Blocker with high speed Laser Blocking

• The Benz IOL Drill

• 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 fi rst 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 profi ling of aspheric surfaces

• Automatic video inspection of haptic milling

ILM-3 Manufacturing Sequence

The fi rst step to starting ILM-3 is loading clean mandrels in

trays into the Tray Feed System, making sure that the

vibratory hopper is full of blanks and the wax applicators on

the Automatic Blank Mounting Machine and Optical Blocker

are full. The next step is to calibrate the lathes Y-Axis to the

Optical Blocker Z-Axis and verify the concentricity of the

Blocker. This will take 1 hour or less. Now IOL lenses can be

ordered in any combination from singles to hundreds at the

Order Entry Terminal. Finished lenses on their second side

mandrels and used fi rst side mandrels are returned to their

trays in the Tray Feed System. Each tray of mandrels and

lenses can be conveniently handled and cleaned using the trays

with the Benz Solvent Cleaning System.

I N T E G R AT E D

L E N S M A N U FAC T U R I N G

( I L M )

26 27

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.

Figure 27

AutomationSoftware

& Database

1. Order Entry &Customer ID

3. BlankMounting(Robotic)

4. 1st Side OpticsLathing & Milling

(Robotic)

5. Optical Blocking(Robotic)

9. Hydration & or Inspection

7. 2nd Side OpticsLathing(Robotic)

10. Packaging &Labeling

8. Polishing

2. Lens Design

6. Deblocking& Cleaning

(Robotic)

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 fi rst side lathes are 100% monitored because all fi rst 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.

I L M -3

28 29

Tray FeedSystem

TransferTrack

Blank Mounting,Deblocking and

Cleaning

DAC MLC

DAC MLC

DAC MLC

DAC MLC

OpticalBlocker

ILM-3

60.0 µm

40.0 µm

20.0 µm

0.0 µm

-20.0 µm

-40.0 µm

-60.0 µm

RO

Err

or (m

icro

ns)

13:00 13:30 14:00 14:30 15:00 15:30

Production

Calibration

Measurement

Production Results for Lathe 002

Production Error Mean = 1.8 µm SD + 1.2 µm

Figure 28

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 specifi c lot of hydrophilic IOL

material (Benz-IOL 25), see Table 12.

Sample lenses were randomly selected from production

orders consisting of 120 lenses of each power, manufactured

using the ILM system.

Following lathing the 1st side optics and milling the haptics,

each part is precision blocked, in the optical blocker, after

the optics have been examined and centered and the radius

measured. This radius data is used to re-calculate the target

radius on the 2nd side optic to ensure optimum target

hitting. Second side optic is then lathe-cut and the dry IOL

de-blocked and cleaned. A sample size consisting of 60 lenses

was selected at random from each Diopter batch. Out of this

sample, a set of thirty (30) lenses were hydrated directly after

lathing (before dry polishing) and a second set of thirty (30)

lenses were polished using the Benz proprietary dry-polish

process followed by hydration. While in the dry-state, we

measured each lens OZ diameter, center thickness and haptic

thickness. Table 13 shows the measured radius of 12 randomly

selected 20 D lenses from a 120-part order along with the data

for CT, haptic thickness and optic diameter.

Using an IOLA model # V2.2.34 from Rotlex, the Diopter

power and MTF of the hydrated lenses were determined for

both sets, before and after polishing. MTF offers a display of

fringe patterns that give visual information on imperfections

in the IOL and can be indicative of defects in a manufacturing

process. Table 14 shows the data for 14 lenses randomly

selected from the set of +20.00 Diopter lenses.

Finally, Table 15 shows a summary of the evaluation data

demonstrating the precision and accuracy of the Benz ILM

system. These validation results indicate that when using the

ILM system to manufacture IOLs, QA time can be signifi cantly

reduced because ILM can be validated for statistical sampling

and analysis for power. ILM results in higher yields, optimum

target hitting, reduced parameter inspection and signifi cantly

higher productivity. Validation of the ILM system, per ISO-

13485 standards, is part of the package when purchasing a

complete ILM system from Benz Research and Development.

ILM performance is guaranteed.

I L M P E R F O R M A N C E

VA L I DAT I O N

30 31

Table 12

Data Input ILM Calculation

Final Lens Diopter Radius (mm) Center Thickness (mm) OZ Diameter (mm)

+28.0 7.80 1.269 5.370

+20.0 11.03 0.967 5.370

+12.0 18.44 0.686 5.370

Manufacturing Parameters for Lenses from ILM Calculations

Table 13

Target 11.030 mm Target 0.967 mm Target 0.270 mm Target 5.370 mm

Barcode # Measured Radius Center Thickness Haptic Thickness OZ Diameter

6269 11.0316 0.971 0.272 5.378

6615 11.0338 0.971 0.271 5.374

5775 11.0371 0.966 0.276 5.379

7414 11.0344 0.968 0.270 5.373

6702 11.0341 0.965 0.268 5.376

7455 11.0371 0.964 0.272 5.369

7481 11.0308 0.970 0.275 5.373

6659 11.0276 0.974 0.274 5.374

6538 11.0341 0.967 0.274 5.369

5541 11.0318 0.964 0.268 5.380

6415 11.0328 0.956 0.274 5.373

6380 11.0298 0.956 0.271 5.376

AVERAGE 11.0329 0.966 0.2721 5.3745

SD 0.0028 0.0056 0.0026 0.0035

Comparison of 1st Side Optics Radius andSemi-Finished IOL to Target Parameters 20 D

1st Side Dry Lathe - Cut IOL

Table 14

Power MTF Power MTF 19.8 0.45 19.8 0.59 19.8 0.60 19.8 0.57 19.8 0.58 19.8 0.56 19.8 0.53 19.8 0.53 19.8 0.55 19.8 0.59 19.8 0.63 19.8 0.58 19.8 0.56 19.8 0.58 19.8 0.54 19.8 0.58 19.8 0.63 19.8 0.56 19.8 0.57 19.8 0.54

19.8 0.56 19.8 0.59 19.8 0.51 19.8 0.59 19.8 0.58 19.8 0.59 19.8 0.54 19.8 0.59 19.80 0.60 AVG 19.80 0.60 0.05 0.046 SD 0.02 0.03

Before Polishing After Polishing

Table 15

Summary of the Data for All Lenses

IOL Power (Dpt) +28.0 +20.0 +12.0 +28.0 +20.0 +12.0

Target Measured Dimension (mm)

Center Thickness 1.269 0.967 0.686 1.262 0.964 0.678

SD 0.020 0.020 0.020 0.006 0.007 0.007

OZ Diameter 5.370 5.370 5.370 5.372 5.374 5.375

SD 0.020 0.020 0.020 0.004 0.004 0.005

Hydrated Power (dpt)

Before Dry Polishing 28.0 20.0 12.0 27.8 19.8 12.0

SD 0.25 0.25 0.25 0.04 0.03 0.06

After Dry Polishing 28.0 20.0 12.0 27.8 19.8 11.9

SD 0.25 0.25 0.25 0.04 0.02 0.05

MTF

Before Dry Polishing 0.43 min 0.43 min 0.43 min 0.46 0.54 0.58

SD 0.03 0.05 0.04

After Dry Polishing 0.43 min 0.43 min 0.43 min 0.48 0.55 0.56

SD 0.02 0.03 0.02

Figure 29

Mea

sure

d F

inal

Pow

er (D

pt)

32

30

28

26

24

22

20

18

16

14

12

10

8

6

ILM Performance

Confidence (R2) = 0.9993

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

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 specifi c 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 verifi cation of power and MTF. Because

of the validated accuracy and repeatability of ILM, 100%

inspection of IOLs for power is not required, only statistical

verifi cation in accordance with your specifi c ANSI AQL Standard.

Profi tability of ILM-3

Using Table 16 you can determine the appropriate gross profi t

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-fi nished lenses.

Per Day Profi tability for An ILM-3 Four Lathe System

Based on the above example, productivity is 1108 machined

lenses per day at a direct cost of US $2.48 per IOL 25UV lens.

The estimated profi tability [(Productivity x ASP) – Direct Cost =

Profi t] using an average sale price (ASP) per unit of US $20.00

would be about $19,060 per day.

ILM-3 Expandability

The ILM-3 software provides for unlimited expansion of

production cells. No additional software is required to operate

increasingly larger systems. To increase capacity starting with

a 2-lathe ILM-3 system, you simply add 2 more lathes.

To increase capacity starting with a full 4 lathe ILM-3 system

you would need a new ILM-3 System, but with only 2-lathes

to start and no new software, only a faster server.

ILM-3 offers expandability without the headaches of expensive

training, turnover, hourly rate growth and an ever expanding

work force. ILM-3 keeps your cost of goods under control for

years to come.

I L M -3

32 33

BENZ RESEARCH & DEVELOPMENTRegistered to ISO-13485 : 2003File No. A7130

Table 16

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 @ x 1.2 $432.00 Operator Cost x 24

Average Consumable 22.5 hrs $80.00 Including $80.00 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

Direct Cost of Intraocular Lenses Manufacturedin the ILM-3 System

Temperature 21ºC + 2

RH 37% + 5 at 21ºC

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

Environmental Requirements

Figure 30

283˝ [7.200m]

224˝

[5.7

00m

]

Space Requirements ILM-3

B E N Z U N I V E R S A L B L A N K M A N U FAC T U R I N G ( U B M )

Manufacturing hydrophilic IOLs from Benz IOL 25 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 effi ciency 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 fi nished 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.

High precision, Fully Automated Manufacturing can be

achieved using a DAC MLC with Benz Autoloader and data

acquisition software. Benz Research and Development

provides a fully validated Universal Blank Manufacturing

(UBM) System utilizing the DAC MLC. We will provide all

documentation for EN13485 validation and certifi cation

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.

Figure 35 shows 5 trays of Universal Blanks being loaded into

the autoloader. Please, read our article in Global Contact on

Automated Manufacturing using the IOL 25 Universal Blank.

U N I V E R S A L B L A N K

M A N U FAC T U R I N G ( U B M )

36 37

Figure 31 Figure 33

Figure 35Figure 34

Figure 32

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 effi ciency 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 effi ciency 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