Corneal Cross-Linking (CXL) for the Treatment of Keratoconus


Farhad Hafezi performing CXL procedure
Farhad Hafezi, MD, PhD performing CXL procedure

Corneal cross-linking (CXL), a newly FDA-approved treatment for keratoconus, uses a combination of ultraviolet-A light irradiation and application of riboflavin (vitamin B2) eye drops to stabilize the cornea. Two members of the USC Roski Eye Institute faculty have been at the forefront of advancing CXL treatment for keratoconus. Farhad Hafezi, MD, PhD, Adjunct Clinical Professor of Ophthalmology at the USC Roski Eye Institute and Professor of Ophthalmology at the University of Geneva, Switzerland was among the earliest investigators in Europe to study and utilize CXL both in the laboratory and in patients with progressive keratoconus and post-LASIK ectasia. J. Bradley Randleman, MD, Professor of Ophthalmology and Director of the Cornea, External Disease, and Refractive Surgery Service at USC, was a principal investigator for both of the FDA-sponsored US clinical trials that generated the data leading to CXL approval in 2016.

Keratoconus occurs when the cornea (the clear, dome-shaped front surface of the eye) thins and gradually bulges outward into a cone shape. A cone-shaped cornea causes blurred vision and may cause sensitivity to light and glare, problems with night vision and sudden worsening or clouding of vision. This may lead to reduced vision that cannot be corrected with eyeglasses.

CXL cover photo

When compared to the two main causes of blindness—cataract and glaucoma—keratoconus affects a small portion of the general population. On a global level, keratoconus is a leading cause for severe visual impairment in children and adolescents. Research has also identified that people with Down Syndrome are at a much higher risk. Early keratoconus has been greatly under-diagnosed in this group, attributing it to the possibility of poor communication or compliance during visual acuity tests.

Hafezi is spearheading a clinical study in Saudi Arabia to better understand the prevalence of keratoconus among Saudi children and adolescents. Current data suggests that keratoconus has a higher incident rate in Middle Eastern countries. The study, in collaboration with Light for Sight Foundation, Salus University, Pennsylvania and King Saud University, Saudi Arabia, plans to enroll more than 1,500 patients. Results are expected by Summer 2017.

Randleman has been evaluating the comparative efficacy of standard and accelerated protocols and investigating the role of corneal epithelial remodeling in determining CXL outcomes.

The two have co-authored multiple publications on CXL and co-edited the first academic textbook on the topic, Corneal Collagen Cross-Linking, in 2013. A second edition came out in late 2016.

Corneal cross-linking is now available at the USC Roski Eye Institute. Please call us at (323) 442-6335 for more information.

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Watch our first CXL patient, Adam, share his story.