Four Year Results Of Four Year Results Of Corneal Crosslinling Corneal Crosslinling (XL) in Keratoconus(XL) in Keratoconus

Fernando Aguilera-Zarate MDFernando Aguilera-Zarate MD Instituto de Ojos de BCInstituto de Ojos de BC Mexicali, Baja CaliforniaMexicali, Baja California MexicoMexico

No Financial InterestNo Financial Interest

CROSSLINKING (XL)CROSSLINKING (XL) ObjectiveObjective1.1. > Corneal Rigidity> Corneal Rigidity Fotopolimerization colagen FibersFotopolimerization colagen Fibers Combination: UV-A + Rivoflabin (vit B2)Combination: UV-A + Rivoflabin (vit B2) > fibrill diameter > fibrill diameter > interfibrillar junctions> interfibrillar junctions > corneal rigidity> corneal rigidity < corneal ectasia progression< corneal ectasia progression < corneal asimetry< corneal asimetry

BIOCHEMICAL CORNEAL XL BIOCHEMICAL CORNEAL XL CHANGESCHANGES

1. Combined application of UVA and riboflavin

riboflavin (vit. B2) Ultraviolet irradiation

2. Production of oxygen radicals

OO22--

3. Induction of collagen cross-links

-CH2-CH2-CH2-CH = NH-CH2-CH2-CH2-CH2-

collagen fibril collagen fibril

C

C

C

H2C

H OH

H OH

H OH

O P

OH

OH

O

H2C

N

NNH

NH3C

H3C

O

O

-

DefinitionDefinition

POLIMERIZATIONPOLIMERIZATION

Chemical Reaction that transforms molecules Chemical Reaction that transforms molecules of low molecular mass (monomers) of low molecular mass (monomers) producing high molecular weight molecules producing high molecular weight molecules (polymers)(polymers)

Used in Odontology since the early 70’sUsed in Odontology since the early 70’s

Used in Tire and Textil Industries for more Used in Tire and Textil Industries for more than 5 decadesthan 5 decades

WOOLENSAK,SEILER

AJO,2003;135:625-627First Report Of Humans Treated by XL

Results:

Regresion KC …………………….72%

< Spherical Equivalent……………1.34 D

< Astigmatism.. ……………………2.01 D

Control Group, progression………..22 %

CROSSLINKING CROSSLINKING OBJECTIVEOBJECTIVE

Document 4 year follow-up changes Document 4 year follow-up changes in Corneal Refractive, Topography in Corneal Refractive, Topography and Aberrometry; and to evaluate and Aberrometry; and to evaluate the Visual Quality Improvement in the Visual Quality Improvement in Keratoconus corneas Treated by Keratoconus corneas Treated by UV-B CrosslinkingUV-B Crosslinking

Material and Material and MethodsMethods

21 patients21 patients 26 eyes (follow-up 4 years)26 eyes (follow-up 4 years) 18-30 years18-30 years Complete ophthalmic evaluation Complete ophthalmic evaluation Inclusion Criteria: Inclusion Criteria:

No concurrent ophthalmic diseases No concurrent ophthalmic diseases KC (I-III with confirmed progression by KC (I-III with confirmed progression by

topography)topography) Corneal paquimetry >400 um at thinnest pointCorneal paquimetry >400 um at thinnest point Normal Cristaline Lens Densitometry (pentacam)Normal Cristaline Lens Densitometry (pentacam) Normal Retinal OCTNormal Retinal OCT Specular Microscopy (Tomey SM 3000)Specular Microscopy (Tomey SM 3000)

Surgery (Corneal Surgery (Corneal Crosslinking)Crosslinking)

Topical Anesthesia (proparacaine)Topical Anesthesia (proparacaine)

Epithelial removal with Amoils Rotatory BrushEpithelial removal with Amoils Rotatory Brush

UVA + B2, impregnatión (12 minutes)UVA + B2, impregnatión (12 minutes)

Irradiatión 30 min (3.2 J / cm2)Irradiatión 30 min (3.2 J / cm2)

Therapeutic Soft Contact Lens Therapeutic Soft Contact Lens (removal until (removal until epithelization)epithelization)

Followup 1-5 days, 1-3-6-9-12-18-24-36- >48 Followup 1-5 days, 1-3-6-9-12-18-24-36- >48 monthsmonths

Results Visual QualityResults Visual Quality

MTF (modular transfer function)MTF (modular transfer function)

Measures visual quality of the eyeMeasures visual quality of the eye

(cornea to retina)(cornea to retina)

PSF (point spread function)PSF (point spread function)

Measures visual quality of an optical system)Measures visual quality of an optical system)

(Eye-Occipital Cortex)(Eye-Occipital Cortex)

Topographic changesTopographic changes

Corneal Asimetry = o´ < Corneal Asimetry = o´ <

Anterior Elevation Anterior Elevation (eliipsoidal) Reduction or (eliipsoidal) Reduction or no changeno change

Posterior Elevation Posterior Elevation (ellipsoidal)(ellipsoidal)

reduction or no changereduction or no change

Reduction of true net power Reduction of true net power

ElevationElevation: Reduction Anterior/Posterior Reduction Anterior/Posterior Elevation. More Reduction in Ectatic AreasElevation. More Reduction in Ectatic Areas

Corneal Aberrometric Corneal Aberrometric ChangesChanges

< Corneal HOA< Corneal HOA

Coma (z3,-1; z3,1) Coma (z3,-1; z3,1) and trifoil (z3,-3; and trifoil (z3,-3; z3,3)z3,3)

Refractive:Refractive:< Irregular Ast./change in < Irregular Ast./change in axis<10°axis<10°

Pachymetric and Corneal Pachymetric and Corneal Power:Power:< optic pachymetry / < total corneal power< optic pachymetry / < total corneal power

Visual Quality:Visual Quality: mtf improvement at lower frequencies(5-10 mtf improvement at lower frequencies(5-10 c/d)c/d)

Visual Quality Improvement Visual Quality Improvement Related with Reduced Spherical Related with Reduced Spherical Equivalent and Reduction Corneal Equivalent and Reduction Corneal HOAHOA

Reduction Reduction Corneal Irregularity IndicesCorneal Irregularity Indices

XL Early Complications (15 d)XL Early Complications (15 d)

Corneal Edema……………………..8/26Corneal Edema……………………..8/26

Epithelial Retardation..…(>6D)……0/26Epithelial Retardation..…(>6D)……0/26

Loss > 1 Lines VA……….………….0/26Loss > 1 Lines VA……….………….0/26

Corneal Haze………………………..2/26Corneal Haze………………………..2/26

Corneal Melting……………………..0/26Corneal Melting……………………..0/26

> IOP……………………………..…..0/26 > IOP……………………………..…..0/26 Endothelial Damage……………..0/26 Endothelial Damage……………..0/26

Late XL complications Late XL complications (>3 m)(>3 m)

Late Haze (grade I)………….……..1/26Late Haze (grade I)………….……..1/26 Loss > 1 Line Vision………………..0/26Loss > 1 Line Vision………………..0/26 Epithelial Defect…………….………0/26Epithelial Defect…………….………0/26 Corneal Melting……………………..0/26Corneal Melting……………………..0/26 > IOP.………………………………...0/26> IOP.………………………………...0/26 Endothelial Damage……….……….0/26Endothelial Damage……….……….0/26 KC Progression……………………..1/26KC Progression……………………..1/26

Disscusion: UVA-C3 Disscusion: UVA-C3 Corneal Crosslinking Corneal Crosslinking

Improves Corneal Biomechanics > RigidityImproves Corneal Biomechanics > Rigidity < Corneal Asimetry< Corneal Asimetry < Corneal Tertiary Higher Order Ab < Corneal Tertiary Higher Order Ab (coma / (coma /

trifoil) trifoil) < Refractive Corneal Power (true net power)< Refractive Corneal Power (true net power) > Visual Quality (MTF y PSF)> Visual Quality (MTF y PSF) < Pachimetry (Corneal Remodeling)< Pachimetry (Corneal Remodeling)

CONCLUSION CONCLUSION 4 Year Followup of 4 Year Followup of Corneal XLCorneal XL

Effective Therapeutic Modality to Effective Therapeutic Modality to Prevent or Reduce progresion of Ectatic Prevent or Reduce progresion of Ectatic Changes associated with KeratoconusChanges associated with Keratoconus

Improves Optical Qualities of CorneaImproves Optical Qualities of Cornea

Minimal Secondary EffectsMinimal Secondary Effects

fernando aguilera-zarate mdfernando aguilera-zarate md

www.institutodeojos.com.mxwww.institutodeojos.com.mxdrfaguilera@gmail.com