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Peripheral optimized CXL and high power Peripheral optimized CXL and high power

Theo SeilerTheo Seiler

IInstitut für nstitut für RRefraktive und efraktive und OOphthalmo-phthalmo-CChirurgie hirurgie (IROC )(IROC )andand

University of ZürichUniversity of Zürich

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thinnest pointsteepest point

PMD PMD

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0 0.5 1.51 2radial distance to apex /

mm

300

500

700

thinnest pachymetry / μm

PMD

KC

PMD vs KC PMD vs KC

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PMD PMD

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PMD PMD

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In the majority of the keratectasia casesIn the majority of the keratectasia cases

the weakest point of the cornea the weakest point of the cornea

that needs CXL most that needs CXL most

is 1 to 3 mm away from the centeris 1 to 3 mm away from the center

CXLCXL

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radial distance / mm

rela

tive d

ep

th

in %

0 1 2 3

50

60

70

80

90

100

0

th

th1

mav

studystudyOCT 1 month post CXL, 10 eyes, OCT 1 month post CXL, 10 eyes,

inhomogeneity of the beam in curve thinhomogeneity of the beam in curve th11

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In order to create a homogeneous CXL-effect also inIn order to create a homogeneous CXL-effect also in

the periphery of the corneathe periphery of the cornea

irradiation with a irradiation with a top hat-profile is not good top hat-profile is not good enough. enough.

3 mm away from the center the light intensity needs 3 mm away from the center the light intensity needs

to be increased to be increased by at least 25% by at least 25%

proposalproposal

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profileprofile

II00

UV-X1000UV-X1000

UV-X2000UV-X2000

AvedroAvedro

0 4mm

4mm

8mm

8mm

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profileprofile

Crosslinking profile of the UV-X2000Crosslinking profile of the UV-X2000

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CXL-types CXL-types

volume-type volume-type

0μm

100μm

200μm

300μm

400μm

500μm

600μm

30 min3.00 mW/cm²

9min10.00 mW/cm²

surface-type surface-type

0.1%0.1%

30 min 30 min

0.5%0.5%

2 min 2 min

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Pseudo-Bowmans Pseudo-Bowmans

CXL-types CXL-types

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CXL-types CXL-types

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CXL-types CXL-types

volume-typevolume-type

CXL-depth 250 to 330 CXL-depth 250 to 330 μμm m

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CXL-types CXL-types

Applications volume-type Applications volume-type (homogeneous riboflavin, low power)(homogeneous riboflavin, low power)

•infectious keratitisinfectious keratitis•melting diseasesmelting diseases•keratoconus ?keratoconus ?

Applications surface-type Applications surface-type (high riboflavin gradient, high power)(high riboflavin gradient, high power)

•refractive laser surgeryrefractive laser surgery•customized CXLcustomized CXL

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conclusionconclusion

1.1. In the majority of the cases a peripheral In the majority of the cases a peripheral CXL is mandatoryCXL is mandatory

2.2. Second generation CXL lightsources need Second generation CXL lightsources need an optimized beam profilean optimized beam profile

3.3. The surface-type CXL works only if the The surface-type CXL works only if the central irradiance guarantees an central irradiance guarantees an illumination time of 10 min and less illumination time of 10 min and less