Effect of the retention ring-assisted continuous application of riboflavin in pulsed-light accelerated corneal collagen cross-linking on the progression of keratoconus

Abstract

BackgroundTo investigate the efficacy and safety of the retention ring-assisted continuous application of 0.1% riboflavin in pulsed-light accelerated corneal collagen cross-linking on the progression of keratoconus.MethodsThe medical records of 20 eyes of 18 patients with progressive keratoconus who received collagen cross-linking at Seoul National University Hospital were retrospectively reviewed. Isotonic 0.1% riboflavin was continuously applied for 10 min using an 8.0-mm retention ring before the irradiation and accelerated cross-linking was applied with 30-mW pulsed-ultraviolet light at a wavelength 365 nm for eight minutes (1 s on/1 s off; 30 mW/cm2, cumulative dose of 7 .2J/cm2) without further intermittent application of riboflavin. Visual acuity, refractive error, topographic index, corneal thickness, and endothelial cell density were evaluated before the operation and at 1, 3, 6, and 12 months.ResultsThe best corrected visual acuity in logMAR improved from preoperative 0.43 to 0.17 in 12 months (p = 0.050). Maximum keratometry decreased from 51.8 D to 50.4 D at 6 months (p = 0.015) and 50.1 D at 12 months (p = 0.0003). Astigmatism decreased from preoperative 5.5 D to 4.1 D at 12 months (p < 0.0001). Thinnest corneal thickness decreased at three and 6 months but recovered in 12 months (p > 0.05). Endothelial cell density decreased at postoperative 1 month (p = 0.02) but gradually recovered in 12 months (p > 0.05).ConclusionsRetention ring-assisted continuous application of riboflavin for 10 minutes in pulsed-light accelerated cross-linking is a comparably safe and effective treatment for halting the progression of keratoconus in 12 months when compared to outcomes of the standard Dresden protocol shown in previous reports.Electronic supplementary materialThe online version of this article (10.1186/s12886-019-1085-2) contains supplementary material, which is available to authorized users.

Effect of Sequential Intrastromal Corneal Ring Segment Implantation and Corneal Collagen Crosslinking in Corneal Ectasia

“…We previously reported that accelerated CXL and conventional CXL had comparable outcomes [14]. As expected, when we combined ICRS implantation with the same accelerated CXL protocol in the present study, we observed visual improvement and reduced refractive errors.…”

“…Patients who had other ocular surface diseases, surgical history or trauma history were also excluded. The data from patients with ICRS implantation only [13] and CXL only [14] were reported previously, and were included in this study for comparison with the ICRS + CXL group.…”

“…The detailed surgical procedure for CXL was reported previously [14]. The corneal epithelium was peeled off and the CCT (≥325 µm) was determined by pachymetry (Pocket II, Quantel Medical, Bozeman, MT, USA).…”

Effect of intermittency factor on singlet oxygen and PGE2 formation in azulene-mediated photodynamic therapy: A preliminary study

“…An efficient pulse intermittency should be in the hundred to several hundred milliseconds range, based on a previous study that used a nanosecond pulsed 670 nm Nd:YAG laser (with peak fluence rate of 1 mW/cm 2 at a frequency of 30 Hz) to irradiate a photosensitizer named 13,17-bis[1-carboxypropionyl]carbamoyl-ethyl-3-ethenyl-8-ethoxyiminoethylidene-7-hydroxy-2,7,12,18-tetra methylporphyrin sodium (PAD-S31) and induce more cytotoxicity in mouse renal carcinoma cells (Renca) than continuous mode irradiation [ 16 ]. Additionally, using pulse mode of light (ultraviolet light at a wavelength 365 nm, 30 mW/cm 2 1 s on/1 s off or intermittency factor 1, cumulative energy density of 7.2 J/cm 2 ) could prevent development of keratoconus for 12 months in human subjects [ 17 ]. To our knowledge, there are no gold-standard recommendations regarding the optimum intermittency factor for effective induction of ROS formation either in vitro or in vivo .…”

Nutrient Supplementation Improves Contact Lens–Induced Corneal Cell Damage Based on a SIRC Cellular Model

“…15,16 Vitamin B2 (riboflavin) facilitates the formation of covalent bonds between collagen fibers, thus stabilizing the structure of corneal cells. 17 In rats, vitamin B2 deficiency resulted in low densities of microplicae and microvilli in the corneal surface layer and the accumulation of corneal cellular debris due to corneal structure damage. 18 Vitamin B5 (pantothenic acid) is metabolized to panthenol in vivo, which promotes the growth of human corneal epithelial cells.…”