Letter to the editor

Bernhard Ralla, Christoph Holtmann, Gerd GeerlingDepartment of Ophthalmology, University of Düsseldorf, Düsseldorf, GermanyIt is with great interest that we read the publication by Kanellopoulos.1 In this the author shows in a group of 21 patients with 46 months of mean follow-up that the new CXL protocol described, where higher fluence UV light is used with shorter exposure, appears to be a safe, comfortable and effective treatment for stabilizing a progressive keratoconus. This is a very valuable observation. The author also concludes, that collagen cross linking may be a promising adjunct treatment in cases, where a risk of post-LASIK-keratectasia is suspected. LASIK for correction of keratectasia is still controversially discussed. If used as a prophylactic treatment to prevent post-LASIK keratectasia, we would like to point out that the cross linking should be performed preferably after the LASIK procedure because the first will impact various steps of the refractive laser treatment.View original paper by Kanellopoulos

The combination of corneal collagen crosslinking with riboflavin and ultraviolet-a irridation and excimer laser surgery.

ErratumRalla B, Holtmann C, Geerling G. Letter to the Editor. Clinical Ophthalmology. 2013;7:243–246.The title of the paper should have been "The combination of corneal collagen crosslinking with riboflavin and ultraviolet-a irridation and excimer laser surgery."Read the original Letter to the Edito

Influence of corneal collagen crosslinking with riboflavin and ultraviolet-a irradiation on excimer laser surgery.

Item does not contain fulltextPURPOSE: Riboflavin/ultraviolet A (UVA) cross-linking (CXL) of corneal collagen is a novel method of stabilizing corneal mechanical properties and preventing progression of keratectasias. This study was conducted to investigate whether CXL influences ablation rate, flap thickness, and refractive results of excimer laser procedures ex vivo. METHODS: Corneal epithelium was removed from enucleated porcine eyes, and CXL was performed with riboflavin 0.1% and UVA radiation (365 nm, 3 mW/cm(2)) for 30 minutes. Control eyes received epithelial abrasion only. Diffusion of riboflavin through the cornea was assessed by using infrared-excited, two-photon microscopy of riboflavin autofluorescence, combined with second-harmonic generation of fibrillar collagen. During phototherapeutic keratectomy, corneal thickness was measured by optical coherence pachymetry. During LASIK for myopia, the flap thickness of microkeratome cuts was measured and the induced refractive change assessed by Placido topography. Data were analyzed by Shapiro-Wilk test and Student's t-test. RESULTS: Multiphoton imaging showed a rapid (30-minute) and even distribution of riboflavin throughout the corneal stroma. No difference in ablation rate was measured in treated and untreated corneas (P = 0.90). Mean flap thickness was increased by 44% in cross-linked corneas (P < 0.01). After LASIK for myopia of 4 to 25 D, the mean corneal refractive change was reduced in CXL-treated eyes by 20.1% (P < 0.05). This effect was less pronounced in thinner flaps. CONCLUSIONS: CXL reduces the amount of refractive change after LASIK for myopia. Although the laser ablation rate is unaffected, CXL results in an increased flap thickness. This study suggests the need for adjustment of microkeratome and laser parameters for LASIK after CXL and indirectly endorses the theory of a direct stiffening effect of CXL.1 augustus 201

Circular RNAs: a new class of biomarkers as a rising interest in laboratory medicine

Circular RNAs (circRNAs) are a distinct family of RNAs derived from the non-regular process of alternative splicing. CircRNAs have recently gained interest in transcriptome research due to their potential regulatory functions during gene expression. CircRNAs can act as microRNA sponges and affect transcription through their complex involvement in regular transcriptional processes. Some early studies also suggested significant roles for circRNAs in human diseases, especially cancer, as biomarkers and potential clinical targets. Therefore, there is a great need for laboratory scientists to translate these findings into clinical tools to advance testing for human diseases. To facilitate a better understanding of the promise of circRNAs, we focus this review on selected basic aspects of circRNA research, specifically biogenesis, function, analytical issues regarding identification and validation and examples of expression data in relation to human diseases. We further emphasize the unique challenges facing laboratory medicine with regard to circRNA research, particularly in the development of robust assays for circRNA detection in different body fluids and the need to collaborate with clinicians in the design of clinical studies