medicontur iols: materials & design meeting/2017...how do we measure chromatic aberration? the abbe...

Medicontur IOLs: Materials & Design

Main Characteristics

| March 2017 | Medicontur | Vision of Expertise | www.medicontur.com |

Material

OpticDesign

BALANCED TECHNOLOGY FOR OPTIMAL IOLs

OPTICAL

PERFORMANCE

STABILITY IN THE

EYE

LOW PCO RATE

LONG TERM

MATERIAL

PERFORMANCE

REFRACTIVE

STABILITY

TECHNOLOGY


MEDICONTUR IOL PORTFOLIO

Hydrophilic IOLs

(25% and 26% water content, clear & yellow)

• Advanced monofocal IOLs (aspheric – neutral

approach)

• Premium Toric

• Premium Multifocal

• Premium Multifocal-Toric

• SML & Add-On IOLs

Hydrophobic IOLs

(clear & yellow)

• Advanced monofocal aspheric IOLs

• Proprietary SEMTE material with the

highest ABBE number (58); Tg (4°C)

• On the market since 2009


OPTIMAL IOL – BALANCED TECHNOLOGY

MATERIAL

• REFRACTIVE INDEX (RI)

• CHROMATIC ABERRATION (ABBE NUMBER)

• BLUE-LIGHT & UV FILTERs

• GLASS TRANSITION TEMPERATURE (Tg)

• GLISTENING

DESIGN

• SHARP EDGE (SE)

• HAPTIC/OPTIC DIAMETER / CHARACTERISTICs

OPTIC

• ABERRATIONs (SPHERICAL, COMA…)

• COD

• PRECISION


Material

OpticDesign



HYDROPHILIC

Material


HYDROPHILIC BENZ 25 (USA)

• There are many hydrophilic IOL materials on the market

DIFFERENT MATERIALs

DIFFERENT TECHNOLOGIEs &

DIFFERENT QUALITY

Medicontur uses BENZ 25, USA (as well as Zeiss, Physiol….)

IMPORTANT!

Distillation of monomers before polymerisation

• Disadvantage: 10% of material loss

BUT

• Advantage: clean, safe material; less prone to opacification and calcification inside a lens

• other companies e.g. Contamac produce without distillation process


EOEMA

36%

HEMA

64%

Mixing hydrophilic and hydrophobic monomers

25% water content after combination of the two monomers, to form a highly

biocompatible polymer

Medicontur foldable raw material : a combination of two monomers

HEMA, highly hydrophilic monomer

• Pure HEMA = 38% water content

• BIOCOMPATIBILITY

EOEMA, hydrophobic monomer

• Approximately 2% water content

• ELASTIC PROPERTIES

• SOFTNESS

HYDROPHILIC BENZ 25


Apart from design, polimer chain length has a

proven effect against cell adhesion :

A long chain acts as a ʺmolecular eyelashʺ

to prevent cell adhesion and protein deposit

Our raw material : low adhesion for a low PCO rate

Anti-PCO behaviour

Hydrogel MMA 26%

MEDICONTUR HYDROPHILIC – BENZ 25


• for FILTERING AS MUCH AS NECESSARY

for PRESERVING AS MUCH AS POSSIBLE

Medicontur natural yellow filter protects the macula against the wavelengths between

390nm and 460nm thus covering the most dangerous zone of « blue light » and

maintaining scotopic vision (over 460nm)

Bi-Flex M yellow filter

NATURAL YELLOW FILTER


SUMMARY: MEDICONTUR HYDROPHILIC IOLs; MATERIAL - BENZ 25

MAIN CHARACTERISTICS

RI 46

ABBE NUMBER 58

BLUE LIGHT FILTER YES; 390-460nm (violett)

ASPHERICITY Neutral

OPTIC Biconvex; Aspheric;

Aberration free

ANGULATION 0°; posterior vaulting

SE 360°; 10um

MANUFACTURING PROCESS LATHE CUT

TECHNOLOGY POLISH FREE


HYDROPHOBIC

Material


Low Contact angle High

Good Adhesiveness Poor

Good Wettability Poor

High Solid Surface Free

Energy

Low

HYDROPHOBICITY & CONTACT ANGLE in NATURE


SPNSO

Berkeley/USA

EMTE S E M T E

Soft Ethyl-Methyl-Tri-Ethylacrylate

• 2008 MEDICONTUR developed SEMTE as the 2nd generation of hydrophobic material

• 2010 – officially launched

• 1st implantation of IOLs – February 2010, Germany

www.assouline.info

SEMTE – MEDICONTUR DEVELOPMENT


SEMTE = GLISTENING FREE

GLISTENING = fluid filled vacuoles that form within the matrix of the lens when exposed to an aqueous environment

Affects Visual Acuity and Contrast Sensitivity

Mechanism unclearRefractive Index (lower the better, aim: close to RI crystalline lens)

Manufacturing (Cast molded)

Non Compatible packaging

Differences between hydrophobic materialsGlistening

Acrysof

Hoya

No glistening reported: (all RI close to crystalline lens)Tecnis

Aurolab

Hanita (Benz Research)

Medicontur

Glistening in HB IOL (Alcon)

(Courtesy by Michael Assouline, MD, PhD)


1,55 1,5451,54

1,52

1,49

1,47 1,47

1,43

Refractive index

REFRACTIVE INDEX AT DIFFERENT HYDROPHOBIC IOLs ON THE MARKET


GLASS TRANSITION TEMPERATURE of the MATERIAL (Tg)

The mechanical parameters of hydrophobic IOLpolymers are dependent on the glasstransition temperature of the material

Tg: the temperature at which the polymertransforms from a rigid glassy polymer to aflexible compliant material

- room temperature for PMMA

- below room temperature (22° C) forhydrophobic material, ensuring easymanipulation such as flexing and rolling - atlower operating room (OR) temperatures, somehydrophobic acrylic materials with higher Tgvalues can behave as rigid materials, in whichcase folding and compressing are morechallenging

- Lower Tg, better manipulation/softer in OR


= Uneven focusing of an optical system that causes

different wavelengths of light to have different focal points,

thus decreasing optical performance

Refractive index: nE = 1.46 (546 nm, 35 °C)ABBEBENZ25 = 58

CHROMATIC ABBERATION

Graphs shows association of RI & ABBE number


2 Dpt

CHROMATIC ABBERATION


ABBE NUMBER

How Do We Measure Chromatic Aberration?

The Abbe number is a measure of the material's dispersion (variation of refractive index with wavelength) in relation to the refractive index. Low dispersion (low chromatic aberration) materials have high values of V.

The higher the Abbe number the lower the chromatic aberration and the higher the retinal image Quality

.

Zhao H., Mainster M. JCRS. 2007 2. Negishi K, et al. Arch Ophthalmol 2001.

Ernst Abbe (1840–1905) the German physicist


1.Zhao H., Mainster M. JCRS. 2007 2. Negishi K, et al. Arch Ophthalmol 2001.

HYDROPHOBIC MATERIALs & Its ABBE NUMBER

0

10

20

30

40

50

60

3742 43

47

55 57


Alcon Crisalline lens Medicontur

2,212

1,72

Dioptric shift (colour components of white light)

Worsening Improvement

HYDROPHOBIC MATERIALS MAY IMPROVE OR WORSEN CHROMATIC

ABBERATION


Chromatic aberration of the eye: to correct or not to correct?


The results of our Optics Express paper suggest than an IOL that corrects both spherical

and chromatic aberrations by combining aspheric and diffractive elements may have the

potential to provide an improvement in the quality of vision in patients after cataract

surgery.

Proff. Pablo Artal is the founder and director of the Laboratorio de Optica at the University of Murcia.

Visual effect of the combined correction of spherical and longitudinal chromatic aberrations

Pablo Artal, Silvestre Manzanera, Patricia Piers, and Henk Weeber

Optics Express, Vol. 18, Issue 2, pp. 1637-1648 (2010) doi:10.1364/OE.18.001637


„the correction of chromatic aberration can improve visual acuity“

Proff. Pablo Artal, the founder and director of the Laboratorio de Optica at the University of Murcia. .


MEDICONTUR – SEMTE : AN INNOVATIVE HYDROPHOBIC MATERIAL

MAIN CHARACTERISTICs

RI 47

ABBE 57

BLUE LIGHT FILTER YES; 380-510 nm

ASPHERICITY Neutral

SE 360°; 10 um

Tg (lowest on the market) 4°C

Glistening Glistening Free

Manufacturing Process Cryolathing


HYDROPHOBIC MATERIAL (SEMTE ) – STRENGHTs

Property of the material Clinical evidence

Reduced tackiness

Unfolding after implantation

(similar to HL IOLs)

Low Tg – 4°C

(lowest on the market)

Improved mechanical properties

(better manipulation during implantation)

Excellent pseudo-plasticity Quick centration

Perfect SE


MAIN CHARACTERISTICs OF HYDROPHOBIC MATERIALs on the MARKET

IOL

manufacturer

Contact angle

with water

Packaging Glass Transition

Temperature (Tg)

Manufacturing

method

Water

content

RI ABBE

number

Alcon 72° Dry 14.0-15.5°C Molding


Material

OpticDesign



Design

“The most important element of a successful IOL is the lens design. IOL must fit properly so that

it is stable in the long term, with minimal potential for decentration. Additionally, IOL design is

a key factor in inhibiting PCO.”Richard L. Lindsrom, MD


MEDICONTUR Bi-FLEX PLATFORM

OPTIC: 6/13mm

DOUBLE-LOOP HAPTICs

| March 2017 | Medicontur | Vision of Expertise | www.medicontur.com | Ma

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by

TN

N

WHAT IS PERFECT SHARP EDGE?

„Intraocular lenses with a radius curvature of less than 10.0 microns appear to have good

PCO protection“

Mayank et al; JCRS; vol.34; 2008

Medicontur „Bi-Flex“ & all „Flex“ platforms

SE 10 microns

SHARP EDGE


„Geometry of the lens with a square posterior optic edge is the most important factor. This feature should be

present in 360° around the optic, as the optic-haptic junction of single piece lenses may represent sites

where the edge barrier effect is absent“

Werner L., Biocompatibility of intraocular lens materials;

2008 Wolters Kluwer Health

Alcon Acrysof – „Achilles heel“ around haptic – the source of PCO

ME

DIC

ON

TU

R B

i-F

LE

XSQUARE EDGE MUST BE PRESENT AT 360°


Comp 3

25 microns

Comp 2

60 microns

Comp 1

35 microns

Bi Flex 677ABY

10 microns

COMPARISON IN DIFFERENT IOLs in OPTIC-HAPTIC JUNCTION


Comp 5 Comp 6Comp 4

No Square Edge at all

at

Optic-Haptic

Junctions

COMPARISON IN DIFFERENT IOLs in OPTIC-HAPTIC JUNCTION


Measurement of radii of Square Edge (SE) at optic-haptic junction by Scanning Electron Microscopy. The IOLs with discontinuity of SE in optic-haptic junction are not included

The smallerthe radius,

The more effectivethe square edge effect

60

35

25 25 2520 10

*Comp = Competitor

SQUERE EDGE HAS NOT THE SAME MEANING AT DIFFERENT PRODUCERS

| March 2017 | Medicontur | Vision of Expertise | www.medicontur.com | Ma

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Polishing free surface

• Maintaining perfect SE

• Hydrophilic intracapsular IOLs

Hydrophilic material

– more difficult to maintain SE of IOLs because

of the hydratation process during production

POLISH FREE technology

– significantly enhancing of SE of IOLs

– Preventing PCO development

POLISH FREE TECHNOLOGY


The specific Bi-Flex closed-loop

haptic design offers adequate resistance

• to a shrinking capsular bag

• haptics that do not overlap

• excellent axial stability

• optimal filling up of the capsular bag

• unmatched centration and stability

90°

90°

B i-F LE X

Bi-Flex design in a rigid ring

91°contact angle with simulation of rigid capsular sac of 9.0 mm diameter.

Note the good contact (homogeneous) of the loops with the capsular equator for their entire length.

In total Bi-Flex has more than

180°contact angle

between its loops

and the capsular bag.

180° CONTACT BETWEEN THE LOOPS & CAPSULA


Medicontur Bi-Flex Average contact angle: 88.8°

Competitor 1Average contact angle: 69°

Experimental simulator with a diameter of 9 mm

Competitor 2 Average contact angle: 64.4°

A unique & patented design

180° CONTACT BETWEEN THE LOOPS & CAPSULAR BAG EQUATOR


Material

OpticDesign



Optic

„Optical performance is critical. If the IOL does not provide the patient with a satisfactory optical

outcome, then the IOL fails from the start.“Louis D. Nichamin, MD



An ABERRATION is a departure of an image-forming optical system from ideal behaviour

Chromatic aberration are caused by dispersion (the variation of index of refraction of a medium with wavelenght

• Longitidunal

• Lateral

Monochromatic aberration are caused by geometry (the shape of teh lens)

• Spherical aberration

• Coma

• Distortion

• Astigmatism

• Field curvature

ABERRATIONs


SPHERICAL ABERRATION - BASICS

42

+ + + =

Vertical

tiltAstigmatism Horizontal

coma

Spherical

aberration

Superimposed

wavefront

Optical aberration when light rays travel through the edges of the lens,

and light rays do not intersect in one focal point

Positive, Negative aberration and Aberration-free lenses

Zernike polynomials are widely used in ophthalmology to characterize

wavefront aberrations. The most significant parameter is the Z(4,0) which

describes the spherical aberration. For example:


Young eye:

• Negative spherical aberration of the young crystalline lens balances

• Positive spherical aberration of the cornea*

• Essentially zero spherical aberration at the age of 19**

With age:

Functional vision is reduced as the aging crystalline lens loses the ability to compensate for

corneal spherical aberration*

*Guirao A, et al. J Opt Soc Am A. 2000;17:1697-1702. **Holzer M. Presented at DOC, 2006.

-+ + +

The Young Lens Aberration in the Aging Lens

Not drawn to scale Not drawn to scale

SPHERICAL ABERRATION


Positive spherical aberration

Aberration-free

Negative spherical aberration

One focal point

Several focal points

Several focal points

Human cornea: +0.27 SA

Medicontur’s IOLs

Competitors’ IOLs


The avarege human cornea has +0.27 μm spherical aberration [1]

The human crystalline lens has a small negative spherical aberration [2]

With age, the positive aberration of the lens increases [3] - blurred vision, reduce contrast sensitivity

SPHERICAL ABERRATION - IN THE EYE


COMPETITORS

IOLs Spherical aberration with a 6.0 mm pupil

Medicontur IOLs 0.00 μm Aberration-free

Bauch&Lomb / SofPort AO 0.00 μm Aberration-free

Rayner / C-felx, Superflex 0.00 μm Aberration-free

PhysIOL IOLs - 0.11 μm Negative SA

Alcon / AcrySof IQ - 0.20 μm Negative SA

Zeiss / Acri.Smart - 0.26 μm Negative SA

AMO / Tecnis - 0.27 μm Negative SA

Table: Spherical aberration of aspheric IOLs. [6]


SA depends on pupil size: The wider the pupil the higher the SA (scotopic vision)[4]

Depth of focus:

- Reduction of aberrations may reduce depth of focus with aspheric IOLs[6]

- Difference in spherical aberrations of up to 20 µm does not produce a clinically

significant difference in depth of focus[5]

Depth of focus (DOF) is the distance in between the object can be moved

backward and forward and still appear acceptably sharp in an image. .

SPHERICAL ABERRATION - IN THE EYE


NEUTRAL ASPHERICITY APPROACH

Without precise wavefront analysis the aberration of thecornea itself is unknown. So the implantation of an IOL

with a negative aberration can result in a drasticdecrease in depth of field.

Neutral approach, the aberration-free IOLs are the bestoptions in these cases.


REFERENCES

[1] Distribution of corneal spherical aberration in a comprehensive ophthalmology practice and whether keratometry can

predict aberration values; George H.H. Beiko, BM, BCh, FRCS(C), Wolfgang Haigis, MS, PhD, Andreas Steinmueller, MS; J

Cataract Refract Surg 2007;33:848–858

[2] The spherical aberration of the crystalline lens of the human eye; George Smith, Michael J. Cox, Richard Calver, Leon F.

Garner; Vision Research 41 (2001) 235–243

[3] Aspheric IOLs can improve image quality for cataract surgery patients; Uday Devgan, MD, FACS; healio article

[4] C constant: New concept for ray tracing–assisted intraocular lens power calculation; Thomas Olsen, MD, PhD, Peter

Hoffmann, MD; J Cataract Refract Surg 2014; 40:764–773

[5] Fellow-eye comparison of 2 aspheric microincision intraocular lenses and effect of asphericity on visual

performance; Mayank A. Nanavaty, DO, MRCOphth, MRCS(Ed), David J. Spalton, FRCP, FRCS, FRCOphth, Kavita B. Gala,

DO; J Cataract Refract Surg 2012; 38:625–632

[6] Wavefront aberrations, depth of focus, and contrast sensitivity with aspheric and spherical intraocular lenses:

Fellow-eye study; Mayank A. Nanavaty, DO, MRCOphth, MRCSEd, David J. Spalton; Cataract Refract Surg 2009; 35:663–671

[7] Analysis of the possible benefits of aspheric intraocular lenses: Review of the literature; Robert Monte´s-Mico´ , OD,

MPhil, PhD, Teresa Ferrer-Blasco, OD, MSc, PhD, Alejandro Cervin˜ o, OD, PhD; J Cataract Refract Surg 2009; 35:172–181

Medicontur IOLs: Materials & Design

OBJECTIVE HANDLING

How to manage competition with confidence


My doctor does not want to use hydrophilic IOLs since hydrophilic material is less stable

with often calcification/opacification

There are many hydrophilic IOL materials on the market

DIFFERENT MATERIALs

DIFFERENT TECHNOLOGIEs & DIFFERENT QUALITY

IMPORTANT!

Distillation of monomers before polymerisation is CRUTIAL for PURITY

• Disadvantage: 10% of material loss

BUT

• Advantage: clean, safe material; less prone to opacification and calcification

inside a lens

• other companies e.g. Contamac produce without distillation process


LOOK AT THE TREND IN PREMIUM MULTIFOCAL IOLs:

2016 – DP AREA STATISTICs

PROOF: since year 1999 over 4.000.000 HL IOLs have been sold & implanted

52%48%

HB Multifocal

HL Multifocal

Medicontur uses the same HL material - BENZ 25 (USA);

as well as Zeiss & Physiol.

HIGH STANDARDS FOR PRODUCTION AT MEDICONTUR

SAFE and HIGH QUALITY HL IOLs are appreciated by surgeons

DO NOT FORGET:

HL material = BETTER UVEAL BIOCOMPATIBILITY


My doctor does not want to use hydrophilic IOLs since hydrophilic IOLs have higher PCO rate

than HB

Statistically PCO occurs sooner and more often in hydrophilic IOLs. But based on many

studies PCO depends on rather design than the material.

PCO rate finally makes a difference in outcomes and patient satisfaction – especially

important in case of multifocal IOLs. The best optical offer will suffer from capsular fibrosis

Yag laser: the later the better

“ Additionally, IOL design is a key factor in inhibiting PCO.”Richard L. Lindsrom, MD


Recent work has shown that the IOL should have a crisp square edge to be effective and electron microscope

shows that although IOLs are sold with a square edge profile there is in fact a great deal of difference in

edge quality between companies. It is relatively easy to get a crisp edge oh hydrophobic polymers but

more difficult with the hydrophilic materials used by many smaller companies. This is because

hydrophilic materials are machined in a dehydrated state and then rehydrated for clinical use. In this

process the lenses lose some of their edge quality. This explains why hydrophilic IOLs tend to get more PCO.

Another factor of relevance is that, ideally the IOL should have a 360° SE and unfortunately many IOLs have a

breach in the edge where optic and haptics meet, causing the so called “Achilles heel” effect in the barrier.

.

Spalton D:Latest Development in intraocular lenses. 09/10 CET; p. 28

The higher incidence of PCO with hydrophilic materials may also be due to the fact that the optic edge with

hydrophilic materials is not as sharp as with hydrophobic materials.

Nanavaty MA, Spalton DJ, Boyce J, et al. Edge profile of commercially available

square-edged intraocular lenses. J Cataract Refract Surg.2008;34(4):677-686.

DESIGN (SE) rather than material is crucial for protection of PCO development


Prospective study; 25 patients; the Medicontur 677 AB IOL in one eye (hydrophilic), and the 877

AB IOL in the contralateral eye (hydrophobic). The two lenses share the same design and sharp

posterior edge.

Follow up to 30 months

Results:

Visual acuity and refraction did not vary between IOLs. Posterior capsule opacification was

very low in this series, and slightly worse for the hydrophobic model. To-date, 3 eyes with

the hydrophilic model and 2 eyes with the hydrophobic model underwent laser posterior

capsulotomy.

Clinical proof: Bellucci et al.: ESCRS 2014: Same design hydrophobic and hydrophilic

intraocular lenses: intra-individual comparison


Clinical proof: WESCR 2014:Helena Gerbec: First results with

Medicontur Bi-flex 677AB hydrophilic aspheric IOL

Retrospective review of 856 eyes of 642 patients

Follow-up: 33 months:

Indications for YAG capsulotomy:

BCVA =/< 0,7 and PCO (Health Insurance Institute of Slovenia standard) or

BCVA reduction by >20% and PCO

RESULTS:

PCO and YAG capsulotomy: 9 eyes (5 patients) - 1%


1. Dexl et al.: ESCRS 2014:Visual Outcome, Patient Satisfaction and Spectacle Independency after Implantation of

Progressive Bi-Flex M. Final Result of a Multicentric study.

2. AF Dunai, K Kranitz, E Juhasz, G Sandor, T Filkorn, ZZs Nagy. Comparison of two multifocal IOL types – short and

medium-term visual outcomes

3. Gyori J.: Long term functional and morphological outcomes and patient satisfaction after cataract surgery with Bi-Flex M

implantation with / without posterior central circular capsulorhexis (PCCC).

4. A. Bachenger, T.Rückl, W.Riha, G. Grabner, A.Dexl: Rotational stability and visual outcome after implantation of a new

toric intraocular lens for the correction of corneal astigmatism during cataract surgery. J Cataract Surgery 2013:

Clinical proof: 1. Bi- Flex-M (HL): 150 consecutive patients (=300 eyes)

1 year follow up; YAG = 0

2. Bi-Flex T (HL): 30 eyes; 1 year follow-up; YAG =0


Medicontur „Flex“ platform

SE 10 microns

My doctor tells that SE is not a issue today, since all companies today

have SE

YES, it is true. Almost all companies claim their IOLs have sharp edge.

BUT

WHAT IS PERFECT SHARP EDGE?

„Intraocular lenses with a radius curvature of less than 10.0 microns appear to have good

PCO protection“

Mayank et al; JCRS; vol.34; 2008


Alcon Acrysof – „Achilles heel“ around haptic – the source of

PCO

ME

DIC

ON

TU

R B

i-F

LE

XSQUARE EDGE MUST BE PRESENT AT 360°

„Geometry of the lens with a square posterior optic edge is the most important factor. This feature should be

present in 360° around the optic, as the optic-haptic junction of single piece lenses may represent sites

where the edge barrier effect is absent“

Werner L., Biocompatibility of intraocular lens materials;

2008 Wolters Kluwer Health


DO ALL COMPANIES HAVE REAL & PERFECT SE?

NO

Recent work has shown that the IOL should have a crisp square edge to be effective and electron

microscope shows that although IOLs are sold with a square edge profile there is in fact a great deal of

difference in edge quality between companies

Nanavaty MA, Spalton DJ, Boyce J, et al. Edge profile of commercially available square-edged intraocular lenses. J Cataract Refract Surg.,

2008;34(4):677-686.

Spalton D:Latest Development in intraocular lenses. 09/10 CET; p. 28


Comp 3

25 microns

Comp 2

60 microns

Comp 1

35 microns

Bi Flex 677ABY

10 microns

CLINICAL PROOF:COMPARISON IN DIFFERENT IOLs in OPTIC-

HAPTIC JUNCTION


Comp 5 Comp 6Comp 4

No Square Edge at all

at

Optic-Haptic

Junctions

CLINICAL PROOF:COMPARISON IN DIFFERENT IOLs in OPTIC-

HAPTIC JUNCTION


Measurement of radii of Square Edge (SE) at optic-haptic junction by Scanning Electron Microscopy. The IOLs with discontinuity of SE in optic-haptic junction are not included

The smallerthe radius,

The more effectivethe square edge effect

60

35

25 25 2520 10

*Comp = Competitor

CLINICAL PROOF: SHARP EDGE HAS NOT THE SAME MEANING AT

DIFFERENT COMPETITORs


My doctor tells that PCO is not a problem since it can be easily treated by

Nd: YAG laser capsulotomy

Yes, it is true,

BUT

YAG capsulotomy may lead to other complications, including a short-term increase

in intraocular pressure, ocular inflammation, cystoid macular edema, and retinal

detachment. Besides, Nd:YAG laser capsulotomy does not improve visualization of

the peripheral retina, increases the overall costs for cataract treatment, and is not

available in large parts of the developing world.


Clinical proofs: IATROGENICITY OF Nd:YAG CAPSULOTOMY HAS

BEEN DESCRIBED IN CLINICAL OBSERVATIONs

REFRACTION7% of eyes experienced a significant change in subjective refraction

Effect of Nd:YAG laser capsulotomy on refraction in multifocal apodized diffractive pseudophakia. Vrijman

V.:JRefract Surg. 2012 Aug;28(8):545-50. doi: 10.3928/1081597X-20120723-03.

MACULAR CHANGESThirty eyes of 30 patients with posterior capsule opacification following phacoemulsification were enrolled

in the study. Patients were classified according to total energy used during Nd:YAG laser capsulotomy (⩽80 mJ = group I, > 80 mJ = group II).

RESULTS: In group I, IOP increased 1 week postoperatively (P = .007) and declined to preoperative

levels at 1 month. In group II, IOP increased 1 week postoperatively (P = .001) and did not return to

preoperative levels during 3 months of follow-up (P = .04). Both groups had increased macular

thickness compared to preoperative levels, but group II measurements were significantly higher 1 week

and 1 month postoperatively compared to group I (P = .004 and .03, respectively).

ARI S, Ophthalmic Surg Lasers Imaging. 2012 Sep: The Effects of Nd:YAG Laser Posterior Capsulotomy on Macular

Thickness, Intraocular Pressure, and Visual Acuity.

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