To determine whether riboflavin and ultraviolet-A (UVA) corneal crosslinking can be used as an alternative therapy to prevent the progression of keratectasia. Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland, and a private clinic, Athens, Greece. Corneal crosslinking was performed in 10 patients with formerly undiagnosed forme fruste keratoconus or pellucid marginal corneal degeneration who had laser in situ keratomileusis (LASIK) for myopic astigmatism and subsequently developed iatrogenic keratectasia. Surgery was performed in 1 eye per patient. Crosslinking induced by riboflavin and UVA arrested and/or partially reversed keratectasia over a postoperative follow-up of up to 25 months as demonstrated by preoperative and postoperative corneal topography and a reduction in maximum keratometric readings. Riboflavin-UVA corneal crosslinking increased the biomechanical stability of the cornea and may thus be a therapeutic means to arrest and partially reverse the progression of LASIK-induced iatrogenic keratectasia.

The Argus II Retinal Prosthesis System (Second Sight Medical Products, Inc, Sylmar, CA) was developed to restore some vision to patients blind as a result of retinitis pigmentosa (RP) or outer retinal degeneration. A clinical trial was initiated in 2006 to study the long-term safety and efficacy of the Argus II System in patients with bare or no light perception resulting from end-stage RP. Prospective, multicenter, single-arm clinical trial. Within-patient controls included the nonimplanted fellow eye and patients' native residual vision compared with their vision with the Argus II. Thirty participants in 10 centers in the United States and Europe. The worse-seeing eye of blind patients was implanted with the Argus II. Patients wore glasses mounted with a small camera and a video processor that converted images into stimulation patterns sent to the electrode array on the retina. The primary outcome measures were safety (the number, seriousness, and relatedness of adverse events) and visual function, as measured by 3 computer-based, objective tests. Secondary measures included functional vision performance on objectively scored real-world tasks. Twenty-four of 30 patients remained implanted with functioning Argus II Systems at 5 years after implantation. Only 1 additional serious adverse event was experienced after the 3-year time point. Patients performed significantly better with the Argus II on than off on all visual function tests and functional vision tasks. The 5-year results of the Argus II trial support the long-term safety profile and benefit of the Argus II System for patients blind as a result of RP. The Argus II is the first and only retinal implant to have market approval in the European Economic Area, the United States, and Canada.

Corneal collagen cross-linking by UVA/riboflavin (X-linking) represents a new method for the treatment of progressive keratoconus and currently is under clinical study. To avoid UVA irradiation damage to the corneal endothelium, the parameters for X-linking are set in a way that effective treatment occurs only in the first 300 microm of the corneal stroma. Here, X-linking not only strengthens the biomechanical properties of the cornea but also induces keratocyte apoptosis. To date, the effectiveness of treatment could be monitored only indirectly by postoperative follow-up corneal topographies or using corneal confocal microscopy. Here we describe a corneal stromal demarcation line indicating the transition zone between cross-linked anterior corneal stroma and untreated posterior corneal stroma. The demarcation line is biomicroscopically detectable in slit-lamp examination as early as 2 weeks after treatment. X-linking was performed in 16 cases of progressive keratoconus, and corneas were examined biomicroscopically and by means of corneal topography and pachymetry before and after treatment. In 14 of 16 cases, a thin stromal demarcation line was visible at a depth of approximately 300 microm over the whole cornea after X-linking treatment. This newly observed demarcation line may result from differences in the refractive index and/or reflection properties of untreated versus X-linked corneal stroma and represents an effective tool to biomicroscopically easily monitor the depth of effective X-linking treatment in keratoconus.

Corneal collagen crosslinking (CXL) with riboflavin and ultraviolet-A light is a method for treating progressive keratectasia. The currently accepted treatment parameters induce collagen crosslinking in the anterior 250 to 350 microm of corneal stroma. To protect the endothelium, CXL inclusion criteria require a minimum corneal thickness of 400 microm after removal of the epithelium. In advanced keratoconus, however, progressive corneal thinning often leads to a remaining stromal thickness of less than 400 microm. We have therefore modified the current treatment protocol by preoperatively swelling thin corneas to a stromal thickness of at least 400 microm using hypoosmolar riboflavin solution. This treatment protocol was performed in a case series of 20 patients, and no complications were observed. Preoperative swelling of the cornea safely broadens the spectrum of CXL indications to thin corneas that would otherwise not be eligible for treatment.

PURPOSE: To study the progression rate of keratoconus and assess the clinical outcome of corneal collagen cross-linking (CXL) with riboflavin and ultraviolet A light in children and adolescent patients up to 3 years after treatment. METHODS: Fifty-nine eyes from 42 children and adolescents (aged 9 to 19 years) with confirmed keratoconus were included in this retrospective interventional cohort study. Refraction, slit-lamp examination, Placido-based corneal topography, and Scheimpflug imaging were performed bilaterally in all patients preoperatively and at 6 and 12 months postoperatively. Maximal keratometry readings (Kmax), corrected distance visual acuity (CDVA), corneal thickness, and the keratoconus index (KI) were analyzed. Follow-up was up to 36 months (mean follow-up: 26.3 months [range: 12 to 36 months]). RESULTS: Fifty-two of the 59 eyes enrolled in this study showed progression, corresponding to a progression rate of 88%. Forty-six eyes were treated by CXL. Maximal keratometry, CDVA, and KI showed significant changes over the follow-up period. However, significant Kmax reduction observed up to 24 months after CXL lost significance at 36 months. CONCLUSIONS: Cross-linking seems to be safe in children and adolescents. Progression of keratoconus occurred in 88%. We propose that awaiting documentation of progression is not mandatory and CXL in children and adolescents should be performed as soon as the diagnosis has been made. However, the effect of arrest of disease progression might not be as long-lasting as in adults and longer follow-up is needed to verify this trend.

To evaluate the efficacy of ultraviolet-corneal cross-linking (CXL) for treating infectious melting keratitis. Five patients with infectious keratitis associated with corneal melting were treated with CXL at the outpatient departments of the Institut für Refraktive und Ophthalmo-Chirurgie and the eye hospital at the University of Zurich. CXL was performed when the infection did not respond to systemic and topical antibiotic therapy. Follow-up after cross-linking ranged from 1 to 9 months. In all cases, the progression of corneal melting was halted after CXL treatment. Emergency keratoplasty was not necessary in any of the 5 cases presented. CXL is a promising option for treating patients with therapy-refractory infectious keratitis to avoid emergency keratoplasty.