Corneal collagen crosslinking is an effective treatment for improving uncorrected distance visual acuity, corrected distance visual acuity, and average and maximum K values.
These are important findings considering the sequelae of keratoconus and ectasia, which include irregular astigmatism, progressive myopia, or visual impairment secondary to stromal scarring.
In addition, optical aberrations can result from the progressive distortion of the cornea in both disorders, making rigid or complex-curvature contact lenses, rather than spectacles, necessary to provide patients with good vision. Despite this, patients can become contact lens-intolerant over time with progressive corneal distortion, according to Peter S. Hersh, MD, and co-authors Steven A. Greenstein and Kristen L. Fry, OD, MS. The investigators recently published the details of their study (J Cataract Refract Surg. 2011;37:149–160).
The ultimate result is consequent biomechanical stiffening of the cornea, said Dr. Hersh, director, Cornea and Laser Eye Institute, Hersh Vision Group and the CLEI Center for Keratoconus, Teaneck, and clinical professor of ophthalmology, UMDNJ-New Jersey Medical School, Newark, NJ.
In their single-center analysis of a prospective, randomized, controlled clinical study, Dr. Hersh and colleagues analyzed the primary visual acuity and refractive and topographic outcomes in patients with keratoconus and post-LASIK ectasia during a 1-year period of follow-up. They also compared the results in the treatment groups with sham and fellow-eye control groups. The study was performed according to the guidelines of the FDA and approved and monitored by an investigational review board.
The patients in the treatment group (58 patients, 71 eyes) underwent standard UVA–riboflavin 0.1% CXL with removal of the corneal epithelium. Forty-nine eyes had keratoconus and 22 eyes developed ectasia after LASIK. The sham control group (41 eyes, 28 eyes with keratoconus and 13 eyes with ectasia) was treated with only riboflavin 0.1% ophthalmic solution and the epithelium was not removed. The study also included a fellow-eye control group (30 eyes, 21 with keratoconus and nine eyes with ectasia) that included patients who did not undergo bilateral crosslinking.