25 Sep Corneal Collagen Cross Linking
Corneal Collagen Crosslinking-(VEGA, Italy)
A novel technique to stop the progressive deterioration of corneal shape in eyes KERATOCONUS, Pellucid marginal degeneration and Post LASIK corneal ectasias.
It utilizes a controlled beam of specific wavelength of Ultraviolet light (UV-A) in combination with Riboflavin drops that are used frequently during the procedure. This combination of UV light with riboflavin induces the photo-chemical reaction within the corneal micro-structure that increases the bonding of corneal fibers and thus makes this cornea strong and prevents further deformation of the cornea.
A video camera attachment enables a better-focused and controlled delivery of UV light specifically only to the front layers of cornea without affecting its inner layers or inside of the eye.
This procedure is done under topical anesthesia i.e. with anesthetic eye-drops and lasts for approximate 60 minutes .It does not involve any cuts inside the eye.
Two techniques can be utilized to perform this procedure.
a. De epithelial-The outermost layer of cornea i.e. epithelium is scraped off at the start of procedure for better penetration of light and riboflavin. The epithelium grows back in 48-72 hours of the procedure. A contact lens is placed at the end of procedure for better control of pain and epithelium healing.
b. Trans epithelial CXL-where outermost corneal layer i.e. epithelium is kept intact and procedure is performed with specialized Riboflavin drop preparation. This procedure can be combined with placement of INTACS rings inside the cornea or laser treatments to correct the shape of cornea partially.
This can be performed in corneas which are thicker than 400 um on ultrasonic pachymeter or OCT. Any cornea thinner than 400 um, in some cases can still be subjected to this treatment with Hypo-tonic Riboflavin drops preparation. The decision to do these eyes remain controversial and the corneal specialist is the best guide to take this decision.
The effect of the procedure is earliest seen after 3 months and may show up to 3 years following treatment. It is indicated for Keratoconus which is progressing. This progression should be preferably documented on Corneal Topography and rarely on glass prescription. It may be worth while attempting in young patients of age between 10-18 years on detection of the condition for the first time .
The side effects are nil except occasional scarring in cases with uncontrolled or improper delivery of UV light.
The corneal shape needs to be monitored at frequent intervals to assess the stabilization of corneal shape.( at 3 months, 6 months , 1 year, 2 year and 3 year of the procedure).