scholarly journals Comparison of corneal biological parameters between transepithelial and epithelium-off corneal cross-linking in keratoconus

2021 ◽  
Vol 14 (7) ◽  
pp. 998-1005
Author(s):  
Bo-Wen Ouyang ◽  
◽  
Han Wang ◽  
Zhen-Duo Yang ◽  
Tan Zhong ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Corneal Thickness ◽  
Biomechanical Analysis ◽  
Cross Linking ◽  
Specular Microscopy ◽  
Biological Parameters ◽  
Ultraviolet A ◽  
Irradiation Intensity ◽  
Biomechanical Responses ◽  
Better Than

AIM: To evaluate the differences in corneal biological parameters between transepithelial and epithelium-off corneal cross-linking in keratoconus. METHODS: In our prospective clinical trial, 40 patients (60 eyes) with progressive keratoconus were randomized to undergo corneal cross-linking with transepithelial (TE group, n=30) or epithelium-off (EO group, n=30) keratoconus. Examinations comprised topography, corneal biomechanical analysis and specular microscopy at 6mo postoperatively. RESULTS: The keratometer values were not significantly different between the TE and EO corneal cross-linked groups in different periods (each P>0.05). The corneal thickness of the EO group was greater than that of the TE group at 1wk after the operation (each P<0.05). Regarding corneal biomechanical responses, the EO group showed a longer second applanation length than TE group (P=0.003). Regarding the corneal endothelial function, standard deviation of the endothelial cell size, and coefficient of variation in the cell area, the values of EO group were larger than those of TE group at 1wk (P=0.011, 0.026), and the percentage of hexagonal cells in EO group was lower than that in TE group at 1 and 6mo (P=0.018, 0.019). CONCLUSION: Epithelium-off corneal cross-linking may strengthen corneal biomechanics better than TE procedure can. However, the TE procedure with a lower ultraviolet-A irradiation intensity would be safer for corneal endothelial function.

scholarly journals Epithelial Remodelling After Epithelium-off Continuous Accelerated Corneal Collagen Cross-linking in Progressive Keratoconus

2021 ◽  
Author(s):  
Junjie Piao ◽  
Ying Li ◽  
Meng Wang ◽  
Sun Joo Kim ◽  
Choun-Ki Joo ◽  
...  
Keyword(s):  
Corneal Thickness ◽  
Anterior Segment ◽  
Cross Linking ◽  
Ultraviolet A ◽  
Corneal Epithelial ◽  
Postoperative Changes ◽  
Uncorrected Distance Visual Acuity ◽  
Minimum Angle ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Abstract Background: To analyse regional corneal epithelial and stromal remodelling after epithelium-off (epi-off) continuous accelerated corneal collagen cross-linking (CXL) for keratoconus (KC).Methods: In this retrospective study, 20 patients (33 eyes) who were treated with epi-off continuous accelerated CXL (KXL system; Avedro, Inc., Waltham, MA, USA). All treatments were performed with ultraviolet-A (UVA) (energy, 7.2 J/cm2; irradiance, 30 mW/cm2), using continuous (4 min) illumination. The postoperative changes in corneal biometric and visual outcomes were compared. The corneal thickness changes were evaluated using anterior segment optical coherence tomography (Optovue). All patients were followed up for 12 months postoperatively.Results: Uncorrected distance visual acuity significantly improved from 1.06 ± 0.49 logarithm of the minimum angle resolution (logMAR) to 0.71 ± 0.37 logMAR at 3 months after epi-off continuous accelerated CXL (p<0.001). The corneal epithelial thickness changes were significant in the inner nasal at -1.48 ± 3.65 µm (p=0.024), -1.76 ± 4.21 µm in the inner superior-nasal (p=0.024), -1.52 ± 4.02 µm in the inner superior (p=0.046), -1.97 ± 4.57 µm in the inner superior-temporal (p=0.018), -2.12 ± 4.46 µm in the outer inferior (p=0.014), -2.15 ± 4.82 µm in the outer inferior-nasal (p=0.022), -1.73 ± 4.45 µm in the outer temporal (p=0.019) at 6 months after epi-off continuous accelerated CXL.Conclusions: Significant regional epithelial remodelling occurs after epi-off continuous accelerated CXL; a more regular corneal thickness profile and keratometric variations were observed after treatment.

scholarly journals Corneal Collagen Cross-Linking with Hypoosmolar Riboflavin Solution in Keratoconic Corneas

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Shaofeng Gu ◽  
Zhaoshan Fan ◽  
Lihua Wang ◽  
Xiangchen Tao ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Corneal Thickness ◽  
Cross Linking ◽  
Ultraviolet A ◽  
Uva Irradiation ◽  
Manifest Refraction ◽  
Corrected Distance Visual Acuity ◽  
The Mean ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Purpose. To report the 12-month outcomes of corneal collagen cross-linking (CXL) with a hypoosmolar riboflavin and ultraviolet-A (UVA) irradiation in thin corneas.Methods. Eight eyes underwent CXL using a hypoosmolar riboflavin solution after epithelial removal. The corrected distance visual acuity (CDVA), manifest refraction, the mean thinnest corneal thickness (MTCT), and the endothelial cell density (ECD) were evaluated before and 6 and 12 months after CXL.Results. The MTCT was 413.9 ± 12.4 μm before treatment and reduced to 381.1 ± 7.3 μm after the removal of the epithelium. After CXL, the thickness decreased to 410.3 ± 14.5 μm at the last follow-up. Before treatment, the meanK-value of the apex of the keratoconus corneas was 58.7 ± 3.5 diopters and slightly decreased (57.7 ± 4.9 diopters) at 12 months. The mean CDVA was 0.54 ± 0.23 logarithm of the minimal angle of resolution before treatment and increased to 0.51 ± 0.21 logarithm at the last follow-up. The ECD was 2731.4 ± 191.8 cells/mm2before treatment and was 2733.4 ± 222.6 cells/mm2at 12 months after treatment.Conclusions. CXL with a hypoosmolar riboflavin in thin corneas seems to be a promising method for keratoconic eyes with the mean thinnest corneal thickness less than 400 μm without epithelium.

scholarly journals Study of retina and choroid biological parameters of rhesus monkeys eyes on scleral collagen cross-linking by riboflavin and ultraviolet A

PLoS ONE ◽  
2018 ◽  
Vol 13 (2) ◽  
pp. e0192718 ◽  
Author(s):  
Mingshen Sun ◽  
Fengju Zhang ◽  
Bowen Ouyang ◽  
Mengmeng Wang ◽  
Yu Li ◽  
...  
Keyword(s):  
Rhesus Monkeys ◽  
Cross Linking ◽  
Biological Parameters ◽  
Ultraviolet A ◽  
Collagen Cross Linking

scholarly journals Comparison of Standard Versus Accelerated Epithelium-Off and Transepithelial Corneal Cross-Linking in Pediatric Keratoconus: An Up-to-date Meta-Analysis

2020 ◽  
Author(s):  
Yuanjun Li ◽  
Yewei Yin ◽  
Tu Hu ◽  
Kaixuan Du ◽  
Ying Lu ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Weighted Mean Difference ◽  
Meta Analysis ◽  
Corneal Thickness ◽  
Cross Linking ◽  
Short Term ◽  
Long Run ◽  
Uncorrected Visual Acuity ◽  
Better Than

Abstract Purpose: To compare the efficacy of four corneal cross-linking (CXL) protocols: standard epithelium-off (SCXL), accelerated epithelium-off (ACXL), transepithelial (TCXL), and accelerated transepithelial (A-TCXL) for pediatric keratoconus.Methods:A comprehensive literature search on the efficacy of SCXL, ACXL, TCXL and A-TCXL in treating keratoconus patients age 18-year or under was conducted using PubMed and EMBASE up to March 2020. Primary outcomes included uncorrected visual acuity (UCVA) and maximum keratometry (Kmax). Secondary outcomes included best-corrected visual acuity (BCVA), central corneal thickness (CCT), and mean refractive spherical equivalent (MRSE). Estimations were analyzed by weighted mean difference (WMD) and 95% confidence interval (95% CI) for the outcomes during observation periods from 6 to 36 months.Results:Eight papers involving total 704 eyes were enrolled. In pediatrics, ACXL resulted in significantly better postoperative UCVA than SCXL at 12-month observation (WMD = 0.08, 95% CI: 0.02 to 0.14, P = 0.007), while SCXL provided statistically better BCVA (WMD = -0.07, 95% CI: -0.12 to -0.01, P = 0.01) and MRSE (WMD = 0.31, 95% CI: 0.06 to 0.56, P = 0.01) than ACXL at 24 months. Furthermore, SCXL provided significantly improved BCVA compared with TCXL at 12- to 24-month observation. (WMD = -0.13, 95% CI: -0.21 to -0.05, P = 0.001). Conclusions:In pediatric keratoconus, although UCVA in short-term follow-up after ACXL was better than that after SCXL, the long-run results showed that SCXL may provide superior visual acuity than either ACXL or TCXL. Further investigation is required to compare the efficacy of different CXL protocols for the management of pediatric keratoconus.

scholarly journals Molecularly imprinted membrane for transport of urea, creatinine, and vitamin B12 as a hemodialysis candidate membrane

2021 ◽  
Vol 19 (1) ◽  
pp. 806-817
Author(s):  
Muhammad Cholid Djunaidi ◽  
Nabilah Anindita Febriola ◽  
Abdul Haris
Keyword(s):  
Polyethylene Glycol ◽  
Vitamin B12 ◽  
Kidney Function ◽  
Cross Linking ◽  
Vitamin B ◽  
Molecularly Imprinted ◽  
Selective Transport ◽  
Molecularly Imprinted Membrane ◽  
Better Than ◽  
Imprinted Membrane

Abstract High levels of urea and creatinine in the blood are a sign of decreased kidney function. To remove these substances from the blood, hemodialysis which utilizes membranes could be used. In this study, a molecularly imprinted membrane (MIM) was synthesized for the selective transport of urea. The synthesis is initiated with the polymerization of eugenol into polyeugenol and then into polyeugenoxy acetate (PA). The PA is then contacted with urea and then used as the functional polymer in the synthesis of MIM with polysulfone as the membrane base, and polyethylene glycol as the cross-linking agent. The result was later analyzed with FTIR and SEM-EDX. The membrane is then used in the transport of urea, creatinine, and vitamin B12 and then compared with the non-imprinted membrane (NIM) performance. By using UV-Vis spectrophotometry, the results showed that the membrane with 10 h heating variation is able to transport more urea and is more selective than NIM; this proves that the urea template on the MIM enables it to recognize urea molecules better than creatinine and vitamin B12. The order of transport from the best results is urea > creatinine > vitamin B12.

Evaluation of corneal endothelium using specular microscopy in patients with obstructive sleep apnea syndrome

2021 ◽  
pp. 112067212110065
Author(s):  
Murat Serkan Songur ◽  
Yavuz Selim İntepe ◽  
Seray Aslan Bayhan ◽  
Hasan Ali Bayhan ◽  
Ender Şahin ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Coefficient Of Variation ◽  
Corneal Endothelium ◽  
Corneal Thickness ◽  
Sleep Apnea Syndrome ◽  
Control Group ◽  
Specular Microscopy ◽  
Obstructive Sleep ◽  
Apnea Syndrome

Purpose: In the present study we evaluate the corneal endothelium using specular microscopy in patients with obstructive sleep apnea syndrome (OSAS). Methods: The study included a total of 100 patients including 35 patients with mild OSAS, 34 patients with moderate OSAS and 31 patients with severe OSAS, and the right eyes of 30 patients as a control group. Patients were examined to exclude the possibility of ocular diseases. Cellular density in the cornea epithelium (cell/mm2), corneal thickness (µ), percentage of hexagonal cells (%) and the coefficient of variation were evaluated using a specular microscope. Results: Corneal thickness was significantly decreased in all OSAS groups when compared to the control group ( p = 0.002), while no significant difference was identified among the OSAS groups. The corneal endothelial cell density, percentage of hexagonal cells and coefficient of variation were significantly different between the OSAS groups and the control group ( p < 0.001). Conclusion: More significant impairments were noted in the corneal endothelium of the patients in the OSAS group than in the control group, and specular microscopy is in valuable in the follow-up and treatment of such patients.

scholarly journals Chemically-Boosted Corneal Cross-Linking for the Treatment of Keratoconus through a Riboflavin 0.25% Optimized Solution with High Superoxide Anion Release

2021 ◽  
Vol 10 (6) ◽  
pp. 1324
Author(s):  
Cosimo Mazzotta ◽  
Marco Ferrise ◽  
Guido Gabriele ◽  
Paolo Gennaro ◽  
Alessandro Meduri
Keyword(s):  
Superoxide Anion ◽  
Hydroxypropyl Methylcellulose ◽  
Anterior Segment ◽  
Preclinical Study ◽  
Cross Linking ◽  
Specular Microscopy ◽  
The Novel ◽  
Power Setting ◽  
Contralateral Eye

The purpose of this study was to evaluate the effectiveness and safety of a novel buffered riboflavin solution approved for corneal cross-linking (CXL) in progressive keratoconus and secondary corneal ectasia. Following the in vivo preclinical study performed on New Zealand rabbits comparing the novel 0.25% riboflavin solution (Safecross®) containing 1% hydroxypropyl methylcellulose (HPMC) with a 0.25% riboflavin solution containing 0.10% EDTA, accelerated epithelium-off CXL was performed on 10 patients (10 eyes treated, with the contralateral eye used as control) through UV-A at a power setting of 9 mW/cm2 with a total dose of 5.4 J/cm2. Re-epithelialization was evaluated in the postoperative 7 days by fluorescein dye test at biomicroscopy; endothelial cell count and morphology (ECD) were analyzed by specular microscopy at the 1st and 6th month of follow-up and demarcation line depth (DLD) measured by anterior segment optical coherence tomography (AS-OCT) one month after the treatment. We observed complete re-epithelization in all eyes between 72 and 96 h after surgery (88 h on average). ECD and morphology remained unchanged in all eyes. DLD was detected at a mean depth of 362 ± 50 µm, 20% over solutions with equivalent dosage. SafeCross® riboflavin solution chemically-boosted corneal cross-linking seems to optimize CXL oxidative reaction by higher superoxide anion release, improving DLD by a factor of 20%, without adverse events for corneal endothelium.

Long term results of accelerated corneal collagen cross-linking in pediatric keratoconus

2021 ◽  
pp. 112067212110183
Author(s):  
Yasin Cinar ◽  
Cagla Cilem Han ◽  
Alparslan Sahin ◽  
Zeba A Syed
Keyword(s):  
Visual Acuity ◽  
Corneal Thickness ◽  
University Hospital ◽  
Long Term Results ◽  
Cross Linking ◽  
Distance Visual Acuity ◽  
The Mean ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Purpose: To evaluate the long term visual, refractive, and corneal tomographic outcomes of epithelium-off accelerated corneal collagen cross-linking (ACXL) in the management of pediatric keratoconus (KC). Methods: This retrospective study included patients under 18 years old with progressive KC who underwent ACXL between 2012 and 2019 at Dicle University Hospital. Complete ophthalmic examination was performed including uncorrected distance visual acuity (UDVA), best spectacle-corrected distance visual acuity (CDVA), manifest refraction, and corneal tomography. Evaluations were performed preoperatively and at 6 months intervals postoperatively. Results: Forty-nine eyes of 49 patients were included in the study. The mean age of patients at the time of ACXL was 14.2 ± 1.8 (range: 9.5–17.3) years. Mean follow up was 4.61 ± 1.90 (range: 2.0–8.1) years. The mean LogMAR UDVA improved from 0.94 ± 0.41 to 0.81 ± 0.43, 0.69 ± 0.41, and 0.67 ± 0.33 after 1, 3, and 5 years respectively ( p = 0.001). The mean LogMAR CDVA improved from 0.58 ± 0.36 to 0.46 ± 0.31, 0.34 ± 0.23, and 0.39 ± 0.27 after 1, 3, and 5 years respectively ( p = 0.015). The mean refractive cylinder improved significantly from 6.01 ± 2.07 diopters (D) to 5.46 ± 1.87, 5.38 ± 2.18, and 5.02 ± 2.31 D after 1, 3, and 5 years respectively ( p = 0.005). As compared to preoperative values, steep keratometry and maximum keratometry were not significantly different ( p = 0.805 and 0.448, respectively) following ACXL, while flat keratometry significantly improved after ACXL ( p = 0.012). Although central corneal thicknesses decreased significantly ( p = 0.029), the decrease in thinnest corneal thickness was not statistically significant ( p = 0.205). Conclusion: Epithelium-off ACXL seems to be effective for halting KC progression with long term clinical benefits in pediatric patients.

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