Corneal Cross-linking For Progressive Keratoconus Research Articles

Corneal Crosslinking in Progressive Keratoconus: Comparison of Dextran-Based and Hydroxypropyl Methylcellulose-Based Riboflavin Solutions Differences in demarcation line depth and 1 yaear outcomes

Keratoconus is a progressive ectatic disorder characterised by irregular myopic astigmatism and loss of visual acuity due to corneal thinning. Corneal collagen crosslinking is the treatment recognised to stop the progression of keratoconus. Our study evaluates and compares visibility and depth of the stromal demarcation line after corneal collagen crosslinking using anterior segment optical coherence tomography between two groups:crosslinking with dextran-based and hydroxypropyl methylcellulose-based riboflavin solutions. Our work proved a better visibility and a deeper demarcation line when we used HPMC-based riboflavin. Also the study revealed that HPMC-based riboflavin is associated with better biomechanical outcomes than dextran-based riboflavin.

Investigation of the Outcomes of Corneal Cross-linking in Progressive Keratoconus

Investigation of the Outcomes of Corneal Cross-linking in Progressive Keratoconus

Topographic Localization of the Demarcation Line after UV Corneal Crosslinking in Progressive Keratoconus

Purpose: To assess the topographic location of the demarcation line in in different areas of the cornea after standard corneal crosslinking. Patients and methods. 12 patients (15 eyes) with keratoconus of stages 1–2 of Amsler-Kruimerich classification were observed. UV cross-linking was performed in all patients according to the standard Dresden protocol with 0.1% aqueous solution of riboflavin. The patients underwent optical coherence tomography of the anterior segment of the eye on “DRI OCT Triton” (“Topcon”, Japan) in different areas of the cornea to assess the location of the demarcation line. Results. Demarcation line was revealed in 1 month after standard corneal cross-linking in most cases (87%). Biomicroscopy showed that DL limited the anterior and middle laers of the stroma from the posterior one. The stromal demarcation line depth according to OCT averaged 305.73 ± 41.08 μm (range of 282–345 μm) at the center, nasally — 215.16 ± 35.5 μm (range of 160–289 μm) and temporally 205,23 ± 32.81 μm (range of 190–276 μm). A significant difference in the depth of DL localization in the central zone of the cornea and a 6 mm zone (p < 0.001) was noted. Conclusion. The corneal stromal (обычно) demarcation line is one of the indicators of the depth of photochemical process of corneal cross-linking. Optimal timing of detection of DL following corneal collagen crosslinking is 2 weeks — 3 months. The depth of DL in the corneal studied areas is different; it is deeper in the central zone than in the peripheral ones.

Epithelium-on Corneal Cross-linking for Progressive Keratoconus: Two-year Outcomes

Epithelium-on Corneal Cross-linking for Progressive Keratoconus: Two-year Outcomes

Demarcation line depth after contact lens–assisted corneal crosslinking for progressive keratoconus: Comparison of dextran-based and hydroxypropyl methylcellulose–based riboflavin solutions

To compare the demarcation line depth after contact lens-assisted corneal crosslinking (CXL) for progressive keratoconus using dextran-based and hydroxypropyl methylcellulose (HPMC)-based riboflavin solutions. Advanced Eye Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India. Retrospective case series. Patients with preoperative epithelium-on (epi-on) minimum corneal thickness between 350μm and 450μm having contact lens-assisted CXL for progressive keratoconus were crosslinked with isoosmolar 0.1% riboflavin in 20% dextran 500 or HPMC 1.1%. The primary outcome measure was the mean demarcation line depth measured 1month postoperatively on anterior-segment optical coherence tomography. The secondary outcome measure was change in endothelial cell density (ECD) 6months from baseline. The study comprised 21 patients (21 eyes, 9 in the HPMC group and 12 in the dextran group). The mean demarcation line depth was deeper in the HPMC group (308.22μm±84.19 [SD]) than in the dextran group (235.33±64.87μm)(P<.04). This difference remained significant (P=.02) even after controllingfor the preoperative lesser epi-on minimum corneal thickness in the HPMC group (385.56±13.81μm) versus the dextran group(413.08±29.58μm)(P<.02). The ECD 6months aftercontact lens-assisted CXL was comparable to the baselinelevels in both groups (P=.19 and P=.09, respectively). During contact lens-assisted CXL, HPMC-based riboflavin seemed to be associated with a deeper demarcation line than dextran-based riboflavin, although both solutions were safe for the endothelium at 6months.

Higher order optical aberrations and visual acuity in a randomized controlled trial comparing transepithelial versus epithelium-off corneal crosslinking for progressive keratoconus.

PurposeThe purpose of this study was to compare the effects of transepithelial crosslinking (trans-CXL) versus epithelium-off crosslinking (epi-off CXL) for progressive keratoconus with respect to the development of higher order aberrations (HOAs) and their effects on visual acuity.Materials and methodsA total of 61 patients were randomized and examined preoperatively and 1, 3, 6, and 12 months postoperatively in an academic referral center. Total corneal HOAs were compared between the two treatment groups using mixed linear modeling. Types of HOAs (coma, trefoil, and spherical aberration) that differed between groups were entered in a multivariable analysis to test their effect on uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA).ResultsThe epi-off CXL group had more flattening in maximal keratometry compared to the trans-CXL group (P=0.02). UDVA did not differ significantly between the groups (P=0.59); however, CDVA was significantly more improved in the trans-CXL group (P=0.02). Horizontal trefoil improved more in the epi-off group compared to the trans-CXL group (P=0.04), whereas the other HOAs were virtually unchanged in both groups. Differences in changes in HOAs between the two groups had no effect on either UCVA (P=0.76) or CDVA (P=0.96).ConclusionAlthough HOAs are clinically relevant determinants of vision quality in keratoconus patients, the change in total HOAs post treatment did not differ between the trans-CXL and epi-off CXL groups. Only horizontal trefoil differed significantly post treatment between the trans-CXL and epi-off CXL groups. However, this difference did not independently affect either UDVA or CDVA. Trans-CXL provides no benefit over epi-off CXL regarding visual relevant HOAs.

Visual and Topographical Outcomes Following Accelerated Trans-Epithelial Corneal Crosslinking in Progressive Keratoconus.

To assess the visual and topographical outcomes following accelerated trans-epithelial corneal crosslinking (TE-CXL) in progressive keratoconus. Case series. Laser Vision Centre, Karachi, from January 2015 to December 2016. Forty-five eyes of 25 patients affected with progressive keratoconus and treated with accelerated TE-CXL with riboflavin (vitamin B2) and ultra-violet A(UV-A) irradiation were enrolled in this study. The visual outcome was measured by ETDRS chart as improvement in best corrected visual acuity (BCVA) of at least one line or more as compared to pre-CXLBCVA. The topographical outcome was measured as decrease in maximum simulated keratometry values, astigmatism and spherical equivalent (SE) and an increase in central corneal thickness (CCT). K-max was defined as the steepest radius of curvature of the anterior corneal surface. SE was measured by subjective refraction, and K-max, astigmatism and CCTby scanning-slit corneal topography. Patients were followed-up 12 months post-treatment. At the end of follow-ups, mean BCVAshowed improvement of one line from LogMAR 0.58 ±0.067 to LogMAR 0.48 ±0.077. Seven (15.5%) eyes showed two lines of improvement while 3 (6.7%) eyes showed worsening of one line in BCVA. The mean K-max flattened by 0.7D. Mean astigmatism and SE decreased up to -0.5D and -0.4D, respectively. Mean preoperative CCTwas 454.31 ±36.34 µm, whereas mean postoperative CCTwas 456.47 ±35.60 µm with an average increase of 2.15 µm. No postoperative complications were reported. Based on topographical outcomes, accelerated TE-CXL is effective in preventing the progression of keratoconus without any safety concerns with improvement of vision in majority of cases.

A New Matrix Therapy Agent for Faster Corneal Healing and Less Ocular Discomfort Following Epi-off Accelerated Corneal Cross-linking in Progressive Keratoconus.

To investigate the hypothesis that a new matrix therapy agent (ReGeneraTing Agent, [RGTA]) would speed up the corneal reepithelialization, improve stromal healing, and reduce ocular symptoms after epi-off corneal cross-linking (CXL). Sixty eyes of 60 patients with progressive keratoconus were enrolled in the study. Epi-off accelerated CXL was performed in all patients. Sixty eyes were randomized into two groups according to use of RGTA eye drops prior to contact lens fitting at the end. Identical medical agents were started postoperatively for the two groups. All participants were monitored on 3 consecutive days after the CXL. Ocular pain, burning, stinging, tearing, photophobia, conjunctival hyperemia, and corneal healing status were evaluated. By day 2, 25 eyes (83.3%) with RGTA revealed complete healing compared to 4 eyes (13.3%) that revealed complete healing in the control group (P < .001). All eyes had complete corneal epithelial defect closure by day 3 in both groups. Ocular pain scores were lower in the RGTA group on days 0, 1, and 2 (all P < .05). Burning scores were lower on days 1 and 2; stinging scores on days 2 and 3; tearing scores on days 2 and 3; and photophobia on days 1 and 2 (P < .05) in the RGTA group compared to the control group. RGTA ophthalmic solution facilitates corneal healing by reconstructing the extracellular matrix in the wound area, leading to an earlier relief of symptoms for patients. [J Refract Surg. 2017;33(3):163-170.].

Accelerated transepithelial corneal cross-linking for progressive keratoconus: a prospective study of 12 months

Background/aimsTo evaluate the clinical results of accelerated transepithelial corneal cross-linking (CXL) in Japanese patients with progressive keratoconus (KCN).MethodsThirty eyes of 19 patients (16 male, 3 female patients) with progressive KCN...

Primary Outcomes of Accelerated Epithelium-Off Corneal Cross-Linking in Progressive Keratoconus in Children: A 1-Year Prospective Study.

Purpose To evaluate corneal transparency following accelerated collagen cross-linking (ACXL) in pediatric keratoconus. Design A prospective interventional case series. Methods This study included 47 eyes (25 patients), aged 9–14 years, with documented progressive keratoconus. After applying 0.1% riboflavin drops, ACXL was performed. Assessment included corrected distance visual acuity (CDVA), uncorrected visual acuity (UCVA), corneal haze, and corneal densitometry in grayscale units (GSU). Result The mean baseline and corneal densitometry peaked at 3 months post-ACXL while central and posterior densitometry showed a statistically significant increase (P < 0.05) and peaked at 8 months postoperatively. By 12 months, densitometry in all corneal layers (P ≥ 0.99) and concentric zones (P ≥ 0.97) reached near baseline values. Slit-lamp graded haze peaked at 1 month to 1.82 ± 0.65 (P < 0.05) and declined to near baseline at 12 months (0.39 ± 0.58). There was a statistically significant increase in the mean UCVA and CDVA at 12 months. Conclusion Total and anterior corneal densitometry peaked after 3 months, while central and posterior densitometry peaked after 8 months. Maximum haze was at 1 month post-ACXL. All corneal layers, concentric zone densitometry and haze reached near baseline values after 1 year. Scheimpflug densitometry showed weak correlation with CDVA over the 12-month follow-up period (r = −0.193).

Determining the efficacy of corneal crosslinking in progressive keratoconus.

Objective:To determine the Efficacy of Corneal Crosslinkage (CXL), using Corneal Topography, in eyes with progressive Keratoconus.Methods:This randomized control trial was conducted at Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan from October 2013 to April 2014. A total of 60 eyes of 30 patients were included who presented with bilateral progressive Keratoconus. Each eye of the patient was randomized either to a treatment group (Group-A) or control untreated group (Group-B) of 30 eyes each. A written informed consent was obtained from each patient, following which corneal crosslinkage (CXL) with topical riboflavin eye drops was performed. Follow up visit was done at three months post operatively, Corneal topography was repeated and recorded.Results:The mean age of the patients was 23.13±7.62 years (range 13 to 39 years). There were 26 males and 34 females patients. The mean simK value at the start of study was 50.94±4.84 diopters in Group-A and 49.73±5.24 diopters in Group-B. At three months follow-up, the mean simK value was significantly lower in Group-A (48.28±4.47) as compared to Group-B (51.11±4.85). Keratoconus improved/ remained stable in 34 (56.7%) eyes while progressive disease was noted in 26 (43.3%) eyes. When compared between the groups, the frequency of efficacy was significantly higher in Group-A (86.7% vs. 26.7%; p=.000) as compared to Group-B.Conclusion:Corneal Crosslinking was found effective in causing regression or halting the progression of disease in patients with progressive Keratoconus at three months follow-up, however, the efficacy of corneal crosslinking was unaffected by patient’s age and gender.

A two-year's results of iontophoresis-assisted transepithelial corneal cross-linking for progressive keratoconus

A two-year's results of iontophoresis-assisted transepithelial corneal cross-linking for progressive keratoconus

Accelerated (18 mW/cm(2)) Corneal Cross-Linking for Progressive Keratoconus: 18-Month Results.

The aim of this study is to report the results of 18 months of follow-up after treatment with accelerated (18 mW/cm(2)) corneal cross-linking in patients with progressive keratoconus. Forty-two eyes of 42 patients with progressive keratoconus were included in this retrospective study. All patients underwent accelerated corneal cross-linking at an irradiance of 18 mW/cm(2) for 5 min (total surface dose 5.4 J/cm(2)). Visual acuity, topographic findings (Kflat, Ksteep, Kaverage, and apical keratometry), and central corneal thickness were evaluated during the 18-month follow-up period. The mean ± standard deviation age of the 16 female and 26 male patients was 24.28 ± 6.32 years (range 14-36). Uncorrected distance visual acuity improved clinically significant from 0.52 ± 0.31 to 0.44 ± 0.25 logMAR (P = 0.031), and corrected distance visual acuity improved clinically significant from 0.34 ± 0.21 to 0.28 ± 0.19 logMAR (P = 0.018). At the last examination during the follow-up period, the flat keratometry (Kflat) decreased from a baseline of 45.65 ± 2.71 to 45.41 ± 2.72 diopters (D) (P = 0.001), the steep keratometry (Ksteep) decreased from 49.20 ± 3.54 to 48.96 ± 3.43 D (P = 0.023), and apical keratometry decreased from 56.62 ± 6.43 to 55.19 ± 5.69 D (P = 0.001), all of them were clinically significant at the 18-month visit. The preoperative values of central corneal thickness changed from 458.95 ± 38.79 to 461.85 ± 41.36 μm 18 months after the operation (P = 0.476). The accelerated corneal cross-linking was found to be effective for the stabilization of progressive keratoconus during the 18 months of follow-up visits.

Corneal biomechanical changes after crosslinking for progressive keratoconus with the corneal visualization scheimpflug technology.

Purpose. To evaluate the effect of corneal crosslinking in progressive keratoconus by applying in vivo corneal visualization Scheimpflug technology. Design. Longitudinal retrospective study. Subjects and Controls. Seventeen eyes of patients treated with corneal crosslinking for progressive keratoconus. Methods. Corneal visualization Scheimpflug technology analyses (research software version 6.07r08) of subjects with progressive keratoconus before and 3 months after corneal crosslinking (CXL) were reviewed retrospectively. t-test (for normal distribution) and Wilcoxon matched-pairs test (if not normally distributed) were used to test for statistically significant differences between pre- and post-CXL analyses. Results. We demonstrated statistically significant differences for the intraocular pressure (median: +3 mmHg, P = 0.004), the central corneal pachymetry (pachy; mean: −35 µm, P < 0.001), the timespan between the air impulse release and the first applanation of the cornea (A1time; median: +0.12 ms, P < 0.05), and the timespan between the air impulse release and the second applanation of the cornea (A2time; median: −37 ms, P < 0.05). Conclusions. With the A1time and the A2time, we identified two parameters that demonstrated a statistically significant improvement of the biomechanical properties of the cornea after CXL. Despite the known initial decrease of the pachymetry after CXL, none of the analyzed parameters indicated a progression of the keratoconus.

Photodynamische Therapie bei infektiöser Keratitis

Photodynamic therapy (PDT) has been used in ophthalmology for the last 10 years particularly for disorders of the posterior pole. In recent years PDT has been increasingly applied for corneal cross-linking in progressive keratoconus. The classical PDT is performed with porphyrins as photosensitizers and illumination with visible light of 630-635nm wavelength and cross-linking with the photosensitizer riboflavin and ultraviolet illumination at 370nm. Illumination of photosensitizers generates free oxygen radicals, which damage the cell membrane or nucleic acids of eukaryotic cells or even microorganisms. By cross-linking a stronger network of collagen fibers can additionally be achieved. Experimental studies have shown that PDT with higher concentrations of photosensitizers may induce necrosis and apoptosis of corneal cells and that survival of herpes simplex virus will be reduced on a LogMar scale by 4-5 lines, of Staphylococcus aureus, Pseudomonas aeruginosa or Candida albicans strains by 1-2 lines. Previous clinical studies have shown that PDT may heal bacterial or even acanthamoeba keratitis. Thus, some authors claim that photodynamic therapy may be a potential alternative in therapy resistant infectious keratitis. However, the limitations of this therapeutic option in particular need further investigation.

Corneal Cross-Linking for Progressive Keratoconus in Children: Our Experience

ABSTRACT Purpose To assess the effect of corneal cross-linking on progressive keratoconus in children. Method In this retrospective study we enrolled nine eyes of nine consecutive children aged 11 to 17 years old who underwent corneal riboflavin-UVA induced cross-linking for progressive keratoconus at the Department of Ophthalmology at Assaf Harofeh Medical Center. They were followed for 6 to 24 months (average 16 ± 8.1 months). Evaluated parameters were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, pachymetry, slit lamp examination and corneal topography. Results Cross-linking resulted in stability of visual acuity in seven of the nine (77.8%) treated eyes. We found a nonsignificant improvement in UCVA and BSCVA with a small reduction of manifest cylinder. Furthermore, there was an improvement in spherical equivalent that was close to statistical significance (p = 0.07). There was 0.86 D reduction of average Kmax value postoperatively (p = 0.36). Most patients (7 of 9, 77.8%) showed a long-term stability or reduction in Kmax. Conclusion In this study, we demonstrated the efficacy of corneal cross-linking in arresting the progression of keratoconus in children. We believe that larger scale studies in this age group should be performed to further establish the relevance of this technique in children. How to cite this article Bakshi E, Barkana Y, Goldich Y, Avni I, Zadok D. Corneal Cross-Linking for Progressive Keratoconus in Children Our Experience. Int J Keratoco Ectatic Corneal Dis 2012;1(1):53-56.

Clinical Results of Riboflavin and Ultraviolet-A-induced Corneal Cross-linking for Progressive Keratoconus in Korean Patients

Clinical Results of Riboflavin and Ultraviolet-A-induced Corneal Cross-linking for Progressive Keratoconus in Korean Patients