Results of Collagen Crosslinking followed by posterior chamber toric implantable collamer lens implantation

in patients with Keratoconus & High Myopia

Dr Rajesh Fogla DNB, FRCS, MMed

Senior Consultant, Corneal Surgeon

Apollo Hospitals, Hyderabad

dr_fogla@yahoo.com

www.corneaclinic.comFinancial Disclosure – No Financial Interest

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Collagen cross-linking

• Collagen cross-linking (CXL) using riboflavin phosphate- UVA (365nm) treatment

leads to a significant increase in mechanical stiffness of the cornea.

• Increase in intra- and inter-fibrillar covalent bonds by photosensitized oxidation.

• Several studies have shown arrest of progression of keratoconus post CXL

Implantable Collamer Lens (ICL)

• Phakic IOL

• Approved for high myopia, thin corneas,

suspicious corneal topography wherein

LASIK is contraindicated

• Safe and predictable

• Reversible

• Visian Toric ICL * corrects astigmatism as

well besides myopia

www.corneaclinic.com*STAAR Surgical Company AG, Nidau, Switzerland

• Keratoconus

– Subset of patients have high myopia

with astigmatism less than 6 diopters

– Best spectacle corrected visual acuity is

often > 20/40 in these patients

– Patients desire better unaided vision

Introduction

In this study we evaluate visual outcome of collagen crosslinking followed by posterior chamber toric ICL implantation in patients with keratoconus & high myopia

Materials & Methods

• Prospective, non comparative, interventional case series of consecutive patients

undergoing Collagen crosslinking followed by ICL implantation between March

2008 to September 2008.

• Keratoconus patients with astigmatism less than 6 diopters, minimal

pachymetry of 400 microns, absence of corneal scarring and best spectacle

corrected visual acuity (BSCVA) of 20/40 or better were included in study.

(specular microscopy & anterior chamber depth as per requirements of ICL

implantation were also assessed)

• Outcomes were measured in terms of uncorrected visual acuity (UCVA), BSCVA,

refraction, topography and adverse events.

Surgical Technique

Collagen CrosslinkingTechnique - Epithelial debridement followed by application of riboflavin phosphate 1% for

30mins and UVA (365nm) exposure for 30 mins. Eye patched with topical antibiotics till epithelial healing, followed by use of topical mild steroids, antibiotics and lubricants for one month

Toric ICL implantationTechnique – Surgery was performed under topical anesthesia in all cases. Axis of toric ICL

was marked at the limbus. Standard technique of implantation recommended by the manufacturer was followed in all cases. Single surgical peripheral iridectomy (PI) was performed at 12 o clock position. Postoperatively patients received topical steroids, antibiotics, & lubricants for one month.

• 19 eyes of 15 patients (Male:Female = 11:4)• All eyes underwent collagen crosslinking (CXL) followed by toric ICL

implantation. Average duration between these two procedures 5.4 months (range 3-9 months)

• Pre CXL average keratometry values 54.60 / 49.95, Post CXL 52.96 / 49.70

Pre toric ICL implantation data

UCVA 20/200 (0.1)

BSCVA 20/40 (0.5)

Sphere (Refraction) -9.84 + 4.98

Astigmatism (Refraction) 3.4 + 1.29

Astigmatism (Corneal topography) 4.65 + 2.21

Anterior Chamber Depth (mm) 3.94 + 0.37

Specular Count (cells/mm2) 2879 + 450

Pachymetry (microns) 461.3 + 38.6

Results

Pre Post

UCVA 20/200 (0.1) 20/40+ (0.62)

BSCVA 20/40(0.5) 20/25+ (0.91)

Astigmatism (Refraction) 3.4 + 1.29 1.08 + 1.15

Astigmatism Corneal Topography 4.39 + 2.15 4.03 + 2.04

Sphere (AutoRefractometer) -9.84 + 4.98 -0.11 + 1.39

Cylinder (AutoRefractometer) 4.65 + 2.21 1.6 + 1.82

All patients had improvement in UCVA & BSCVA,

Mean improvement of 5 lines of UCVA & 2 lines of BSCVA.

None of the patients lost any line of BSCVA.

No progression of keratoconus was noted at last follow up. (mean follow up 14

months)

Results

Collagen Crosslinking –

Trace corneal haze noted at 2-4 weeks post CXL which resolved by 8 weeks

None of the patients lost BSCVA post CXL

Toric ICL implantation

Intraoperative - Nil

Postoperative

•Pupillary block glaucoma 1 eye, due to blockage of tiny PI which

resolved following Nd YAG laser enlargement

•Rotation of IOL requiring IOL repositioning 1 eye

•Excessive vaulting (1000 microns) 1 eye, resolved at one month postop

possibly due to trapped viscoelastic behind IOL

Complications

Discussion

• Keratoconus patients with astigmatism less than 6 diopters often have

BSCVA of > 20/40. If associated with high myopia contact lens wear

becomes necessary.

• Keratoconus is a progressive condition. CXL is effective in stabilizing

progression of keratoconus

• In our study Toric ICL implantation provides fairly accurate correction of

spherical power, & reduces astigmatism significantly to improve quality of

unaided vision in keratoconic eyes with high myopia.

• Residual astigmatism of < 1 diopter may require spectacle correction

Conclusion

• Implantation of posterior chamber toric ICL to correct

refractive error in patients with stable keratoconus appears to

be a safe & effective procedure.

• Collagen crosslinking is essential to ensure stability of

keratoconus prior to ICL implantation.

Thank You

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