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Corneal collagen cross-linking with riboflavin (C3R) with Topography Guided Laser Surface Treatment (C3R + Topo guided PRK)

Corneal collagen crosslinking (C3R/ CXL) is a well-accepted and welcome addition to treatment options for keratoconus. Before C3R was approved, treatment options to rehabilitate vision were quite limited, mostly to contact lenses and when they failed one needed to undergo a penetrating keratoplasty (Corneal Transplant or Grafting).

Keratoconus is a known progressive disorder. All modalities of treatment whether it is glasses, contact lenses, INTACS or Phakic IOL's, all correct the refractive error secondary to the cone formation; they do not treat the keratoconus. Reason tells us that anything which is progressive first needs to be stopped and for that there is only one treatment that is available which is C3R or CXL.

Alternative Treatments for Keratoconus

Alternative treatments like Intacs, Rings, Semi soft or rigid lenses, are all temporary treatments. They are not very effective in controlling the condition and also lead to many other visual problems. With Intacs there are subjective complaints about vision like haloes, glare, irregular astigmatism, or monocular diplopia [double vision while seeing through one eye], which can persist. These are not compounded by C3R

Indications for C3R

Keratoconus

LASIK induced ectasia

PMCD-Pellucid Marginal Corneal Degeneration

C3R

We have over 2 years’ experience with C3R; results have been very promising with the slowing or cessation of keratoconus progression in 100% of eyes. The average amount of topographic improvement we have observed is about 2 D.

C3-riboflavin has also been shown to be effective for stabilizing keratoconus as well as most LASIK-induced ectasias

C3R + Topo guided treatment

We now perform treatments which combine C3R with an excimer laser surface treatment. We use the advanced Concerto excimer laser (WaveLight) for the topography-guided treatment.

This is only possible if the Corneal thickness is enough for both treatments and if the topography maps are found suitable for treatment.

Advantages of C3R combined with Laser Surface Treatment:

• Improves the corneal asymmetry.
• The synergistic improvement of shape, based on the C3R effect, allows us to reduce the laser treatment by approximately 50%.
• An improvement in visual acuity
• Better visual rehabilitation and improves vision with contact lenses and glasses by normalizing the corneal surface and reducing irregular astigmatism.
• Refraction remains stable for years.
• If the refraction is small enough, the total refractive error may be reduced
• Patients are easier to fit with contact lenses, which are also better tolerated than before.
• Increased functionality and eliminated need for corneal grafting or transplant are also benefits of the combined treatment.
   

Combining C3R treatment with a topography-guided treatment leads to better visual rehabilitation and improves vision by normalizing the corneal surface and reducing irregular astigmatism. A topography-guided surface treatment is followed by C3-riboflavin.

We perform this topography-guided laser + C3R with epi-off. There is sometimes a mild initial post procedure haze, but it resolves with treatment.

This combined treatment has produced remarkable improvements in corneal Topography. The general changes produced during C3R + Topo guided PRK are flattening of the cone and improvement of the overall shape. This occurs because the combined treatment flattens the steepest area (ie, inferior) and steepens the flattest area (ie, superior).

Safety Issues

Recently, safety issues have been resolved and confirm that the endothelium, lens, and retina are not involved in any potential or real damage after the treatment.

There is some concern regarding the technique (ie, transepithelial treatment vs treatment with de-epithelization, which is doing C3R with Epithelium on or off?). We definitely advise with Epithelium off since there is no risk of damaging the retina or macula this way and a stronger cornea as the riboflavin is soaked into the cornea well.

This procedure has the necessary approval in Europe (CE) where it originated from.

What other Experts Say

“I started using this modality 4 years ago to treat post-LASIK ectasia. So far, I have treated more than 200 cases and have presented and published our results, which are encouraging. I am a strong believer in combining C3-riboflavin treatment with a conservative topography-guided treatment to better visually rehabilitate these patients. I do not wait to do this after the C3-riboflavin treatment. Instead, I perform a conservative topography-guided PRK followed by C3-riboflavin often deal with some postoperative haze, but it resolves with conservative treatment. The reward is that the refraction remains stable for years.” ~ Dr Kanellopoulos

[John Kanellopoulos, MD, is Director of Laservision Eye Institute, in Athens, Greece. He is Attending Surgeon for the Department of Ophthalmology at the Manhattan Eye, Ear, & Throat Hospital, in New York and Clinical Associate Professor of Ophthalmology at New York University Medical School].

“As an American clinician, I anxiously await US Food and Drug Administration (FDA) approval so that clinical studies may begin” ~ Dr Trokel

[Stephen L. Trokel, MD, is a Professor of Clinical Ophthalmology at Columbia University, in New York City, New York]

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