Crosslinking treatment of progressive keratoconus: New hope
ABSTRACT A new method has been introduced for the treatment of progressive keratoconus using collagen crosslinking by the photosensitzer riboflavin and ultraviolet A-light. Biomechanical measurements have shown an impressive increase in corneal rigidity of 328.9% in human corneas after crosslinking.
The 3 and 5-year results of the Dresden clinical study have shown that in all treated 60 eyes the progression of keratoconus was at least stopped ('freezing'). In 31 eyes there also was a slight reversal and flattening of the keratoconus by up to 2.87 diopters. Best corrected visual acuity improved slightly by 1.4 lines. So far, over 150 keratoconus patients have received crosslinking treatment in Dresden. Laboratory studies have revealed that the maximum effect of the treatment is in the anterior 300 mum of the cornea. As for the corneal endothelium, a cytotoxic level for endothelium was found to be 0.36 mW/cm which would be reached in human corneas with a stromal thickness of less than 400 mum.
Collagen crosslinking by the photosensitzer riboflavin and ultraviolet A-light is an effective means for stabilizing the cornea in keratoconus. Collagen crosslinking might become the standard therapy for progressive keratoconus in the future diminishing significantly the need for corneal transplantation. Preoperative pachymetry and individual control of the ultraviolet A-irradiance before each treatment are mandatory. The treatment parameters must not be varied.
- SourceAvailable from: Sheetal Brar
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- "Refractive surgery in high myopia with thinner corneas and borderline topography is a challenging decision, with the most feared complication being regression and postoperative ectasia    . Collagen cross-linking (CXL) has been proven to be an effective modality to strengthen and stabilize the cornea in keratoconus and ectasia after corneal refractive surgery       . "
ABSTRACT: Purpose. To study the safety and clinical outcomes of ReLEx SMILE with accelerated cross-linking in individuals with thinner corneas, borderline topography, and higher refractive errors. Methods. Eligible patients first underwent SMILE procedure for correction of myopic refractive error. Following the removal of lenticule, 0.25% riboflavin in saline was injected into the interface and allowed to diffuse for 60 seconds. Finally, eye was exposed to UV-A radiation of 45 mW/cm(2) for 75 seconds through the cap. Total energy delivered was 3.4 J/cm(2). Results. 40 eyes of 20 patients with mean age of 26.75 ± 5.99 years were treated. Mean follow-up was 12 months ± 28.12 days. Mean spherical equivalent (SE) was -5.02 ± 2.06 D preoperatively and -0.24 ± 0.18 D postoperatively. The mean central corneal thickness (CCT) and keratometry changed from 501 ± 25.90 µm to 415 ± 42.26 µm and 45.40 ± 1.40 D to 41.2 ± 2.75 D, respectively. Mean uncorrected visual acuity (UCVA) was 20/25 or better in all eyes. No eyes lost lines of corrected distant visual acuity (CDVA). There were no complications like haze, keratitis, ectasia, or regression. Conclusion. Based on the initial clinical outcome it appears that SMILE Xtra may be a safe and feasible modality to prevent corneal ectasia in susceptible individuals.Journal of Ophthalmology 07/2015; 2015(6):263412. DOI:10.1155/2015/263412 · 1.43 Impact Factor
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- "The concept of using collagen cross-linking photochemically induced, for increasing corneal stiffness, as a conservative method to stabilize ectasia progression was first conceived in Germany in the 1990s by Theo Seiler and collaborators    . Collagen cross-linking (CXL) opened a new horizon for conscious biomechanical manipulation of the cornea , which uses the concept of biomechanical customization of therapeutic and refractive corneal surgery . "
ABSTRACT: Corneal cross-linking (CXL) is increasingly performed in ophthalmology with high success rates for progressive keratoconus and other types of ectasia. Despite being an established procedure, some molecular and clinical aspects still require additional studies. This review presents a critical analysis of some established topics and others that are still controversial. In addition, this review examines new technologies and techniques (transepithelial and ultrafast CXL), uses of corneal CXL including natural products and biomolecules as CXL promoters, and evidence for in vitro and in vivo indirect effectiveness.Journal of Ophthalmology 08/2014; 2014(890823):9 pages. DOI:10.1155/2014/890823 · 1.43 Impact Factor
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- "Corneal collagen crosslinking (CXL), using ultraviolet-A (UVA) radiation and the photosensitizer riboflavin, was recently introduced for the treatment of progressive keratoconus.12 In several studies, the method has shown a positive effect on the biomechanical1345 and biochemical678 stability of the cornea. "
ABSTRACT: A pilot investigation to transfer the established corneal collagen crosslinking (CXL) procedure in European eyes into clinically affected African eyes and to optimize the treatment by adapting the riboflavin composition. CXL was performed in 15 eyes (11 patients) with advanced stages of keratoconus in the Eye Clinic of Bafoussam in the West Region of Cameroon. The following six riboflavin compositions with different portions of active swelling additives were applied: Solution 1 (0.5% methylhydroxypropylcellulose [MHPC]), solution 2 (1.0% MHPC), solution 3 (1.7% MHPC), solution 4 (5% dextran), solution 5 (10% dextran) and solution 6 (no active swelling ingredient). The central corneal thickness (CCT) was measured by ultrasound pachymetry before and after de-epithelialization and at least every 10 min during CXL. THE APPLICATION OF THE RIBOFLAVIN SOLUTIONS RESULTED IN THE FOLLOWING MEAN FINAL CCT VALUES: 172 ± 15% using solution 1 (60 min/n = 5); 183 ± 8% using solution 2 (60 min/n = 5); 170% using solution 3 (60 min/n = 1); 80% using solution 4 (45 min/n = 1); 99% using solution 5 (45 min/n = 1) and 150 ± 13% using solution 6 (50 min/n = 2). The combination of riboflavin compositions with swelling and stabilizing effects on the corneal stroma seems necessary in African eyes with advanced keratoconus. Further studies are required to confirm these primary results.Middle East African journal of ophthalmology 03/2014; 21(1):66-71. DOI:10.4103/0974-9233.124103