Corneal Collagen Cross-linking For The Treatment Of Keratoconus

Dr. A. Arafat, M.D.,

Al-Noor Eye Center,

Specialized Arab Hospital

Nablus, Palestine

An Everyday Storyيوميا مثلها نصادف حالة

• A 17-year old female patient presented for changing her glasses. She last changed them 6 months ago.

Corneal cross linking uncorrected visual acuity

• Right eye : 6/60

• Left eye: 6/24

Corneal cross linking Autorefractor Readings

• Right : -2.50/-0.75 Axis 51

• Left : -2.25/-4.50 Axis 141

Corneal cross linking Best spectacle corrected visual acuity

• Right eye: -2.25/-0.50 Cyl. Axis 65 = 6/6

• Left eye: -1.00/-1.00 Cyl. Axis 95 = 6/6

Corneal cross linking Clinical Examination

• No detectable anterior segment abnormality in either eye

• No fundus abnormality in either eye

Introduction

Methods of Management of Keratoconus

Classical Methods:

• Glasses• Rigid gas-permeable contact lenses• Penetrating keratoplasty

Methods of Management of Keratoconus

New Methods:

• Glasses• Rigid gas-permeable contact lenses• Corneal cross linking• Intracorneal rings• Phakic intraocular lenses• Deep Lamellar keratoplasty• Penetrating keratoplasty

Corneal cross linking

• Useful to stop the progression of the disease

• Minimal improvement in vision

• Minimal decrease in K-readings

• Can be done till age of 38 years

• The earlier the keratoconus the better

• Corneal thickness <400 microns

Corneal cross linking Work-up

• Complete ophthalmologic examination• Uncorrected visual acuity [UCVA],• Best spectacle-corrected visual acuity

[BSCVA]• Keratometry • Corneal topography & tomography

(Pentacam)

Patient Inclusion Criteria

• Pachymetry >400 microns

• K readings <60D

• No central scarring

• No herpes simplex keratitis

Corneal cross linking Study Procedure

• Topical anaesthesia & povodine iodine

• Corneal epithelium is removed

• Riboflavin eye drops are applied Q 3 minutes for 30 minutes

• flare in A.C. is checked

• Pachymetry: if less than 400 microns hypotonic riboflavin is used Q 15 seconds till thickness is 400 or more

Corneal cross linking Study Procedure-continued

• Cornea is exposed to ultraviolet rays for 30 minutes (10 minutes in new machines)

• Riboflavin still applied Q 2 minutes using UV-X machine

• A bandage contact lens is applied

• Antibiotic & steroid eye drops are applied

• Patient is seen next day

Patient Treatment

Corneal cross linkingFollow up

• Contact lenses are removed after 3-4 days

• Eye drops are tapered over one month

• Further management by glasses, RGP contact lenses or intracorneal rings

Corneal cross linkingComplications

• Infection: Rare

• Corneal haze: Temporary

• Corneal oedema: Transient

• Corneal endothelial decompensation: Not seen in our series

Conclusions

• The procedure is effective & safe

• The main effect is stabilising

• Probably best for recent onset, milder, younger, progressive cases

Recommendations Evidence of progression

• Make use of : serial refractions ,medical records and old glasses)

• Any change greater than 0.50 D from the above could point to unstable refraction

• Below 20 years of age: No need for evidence of progression