Keratoconus, the most common primary ectasia (or thinning) of the cornea, is characterized by localized corneal thinning with subsequent protrusion leading to irregular astigmatism and high myopia (or near sightedness). Visual loss occurs primarily from irregular astigmatism and myopia and secondarily from corneal scarring. Keratoconus affects vision and lifestyle of 1 in 2,000 people worldwide. Ultimately, about 12-20% of the affected individuals require a corneal transplantation at a relatively young age.
Corneal collagen crosslinking (CXL) has been shown to effectively halt the progression of early to moderate keratoconus and other types of ectasia which can happen after refractive surgery, ie. LASIK (also known as “post-refractive surgery ectasia). As a result, corneal collagen cross-linking can delay or prevent corneal transplantation in patients with Keratoconus or post-refractive surgery ectasia.
CXL works by making crosslinks in the collagen fibers which are the natural “anchors” within the cornea, thereby strengthening and “hardening” the cornea so that it does not continue to thin and bulge. During the corneal crosslinking treatment, vitamin drops made of riboflavin are placed onto the cornea, which is then activated by ultraviolet light. This process has been shown in laboratory and clinical studies to increase the amount of collagen crosslinking in the cornea and strengthen the cornea.
Collagen crosslinking is not a cure for keratoconus. The aim of this treatment is to halt progression of keratoconus, thereby preventing further vision loss and the need for corneal transplantation. Glasses or contact lenses will still be needed following the crosslinking treatment (although there may be a change in the prescription) to clear the vision fully.
This procedure was developed in Dresden, Germany and has been shown to slow or halt the progression of keratoconus in many published trials around the world. CXL has been practiced internationally for over a decade with promising results. In the United States, CXL is undergoing national trials to obtain approval by the US Food and Drug Administration (FDA).
Columbia University has been at the forefront of keratoconus research and treatment. We were one of the first to participate in the national FDA trials looking at the efficacy of corneal collagen crosslinking. Our expert clinicians in the division of Cornea and Refractive Surgery, Dr. Leejee H. Suh and Dr. Stephen L. Trokel , currently provide various protocols for Corneal Collagen Crosslinking (CXL) for keratoconus and post-refractive surgery ectasia. We also provide CXL for severe corneal infections (keratitis) that does not resolve with medical therapy. Finally, we provide various surgical options for those with advanced keratoconus who will ultimately need corneal transplantation.
Our clinicians also collaborate with our basic scientists who investigate the pathogenesis, early detection, prevention, and treatment of keratoconus. The laboratory group run by Dr. David Paik is currently investigating cellular pathways implicated in the keratoconus pathogenesis and the study of proteins in keratoconus corneas. They are also investigating alternative agents that induce crosslinking of the cornea without ultraviolet light radation and come in topical eyedrop forms. The laboratory group run by Dr. Ronald H. Silverman is currently investigating cutting-edge technology of high-resolution imaging systems, ie. ultra-high resolution ultrasound, with capability for 3D imaging for non-invasive cornea topographic analysis, to allow for earlier diagnosis of keratoconus. The benefit of identifying those with early keratoconus would be that those with early disease can prevent further progression with corneal collagen crosslinking. They are also investigating novel methods of introducing riboflavin into the cornea without removing the epithelium.