Corneal Collagen Cross-linking For Keratoconus Research Articles

Accelerated versus conventional corneal collagen cross-linking for keratoconus: A meta-analysis of randomized controlled trials.

To systematically compare the effectiveness of conventional corneal collagen cross-linking (CCXL) protocols and accelerated corneal collagen cross-linking (ACXL) protocols in cases with progressive keratoconus. The Cochrane library, EMBASE, MEDLINE, PubMed, and Web of Science databases were searched for randomized controlled trials (RCTs). Outcomes were clinical results and changes in corneal properties. Standardized mean differences (SMD) and 95% confidence interval (CI) were used to estimate the clinical consequences. All outcomes were distributed by different follow-up durations (6 months, 12 months, and > 12 months). We also compared maximum keratometry (Kmax) and best spectacle-corrected visual acuity (BCVA) in subgroups, which were categorized by the discrepant impregnation time period of riboflavin. We included 14 RCTs that met the eligibility criteria in this meta-analysis. At the last follow-up, CCXL was superior in postoperative change in demarcation line (SMD: -1.573; 95% CI: -2.897 to -0.248) and in Kmax (SMD:0.302; 95% CI: 0.071 to 0.533), whereas ACXL provided a significantly lower reduction in central corneal thickness (SMD: 0.498; 95% CI: 0.125 to 0.871). No differences in the changes in uncorrected visual acuity, BCVA, manifest refraction spherical equivalent, corneal biomechanical properties, and the endothelial cell density were found among both groups. CCXL was superior to ACXL in greater corneal flattening and deeper demarcation line, while ACXL seemed to cause less reduction in CCT and allow for earlier UDVA stability. To clearly define the comparative safety and clinical consequences of the different regimens of CXL, more RCTs are required.

Corneal Collagen Cross-linking for Keratoconus in Pediatric and Developmentally Delayed Patients.

Corneal cross-linking (CXL) is the standard of care in patients with keratoconus but presents unique challenges in children and developmentally delayed patients. We present our clinical decision-making algorithm, CXL surgical technique, and outcomes in these groups. A retrospective chart review was undertaken at a tertiary referral center of all patients who underwent CXL for keratoconus at University of Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh between October 1, 2017, and April 1, 2021. Demographic information along with preoperative, intraoperative, and postoperative ophthalmic examination findings were collected. The main outcome measures were indications of CXL, postoperative complications, and visual acuity (VA). Forty-eight eyes of 34 patients [21 patients (30 eyes) with developmental delay (DD) and 13 patients (18 eyes) with no DD (NDD)] underwent epithelium-off, standard CXL. General anesthesia was used for CXL in all patients except for 3 with NDD. A temporary central tarsorrhaphy was performed in all patients with DD and 7 patients with NDD. The remaining got a bandage contact lens. There were no immediate postoperative complications. A trend toward improvement in VA was noted postoperatively. The mean logMAR VA (with habitual correction) was 0.67 preoperatively and 0.57 postoperatively (P = 0.3) in DD and 0.52 and 0.36, respectively (P = 0.13), in NDD. This retrospective review presents a technique for assessment and treatment of keratoconus in children and those with DD. Our technique ensures timely diagnosis and provides a safe method for CXL in these groups. Temporary central tarsorrhaphy is a well-tolerated option to reduce postoperative pain.

A Standardized Protocol of Simultaneous Transepithelial Phototherapeutic Keratectomy (PTK) Followed by Corneal Collagen Crosslinking for Keratoconus.

To report outcomes in patients with progressive keratoconus who underwent a standardized protocol of transepithelial phototherapeutic keratectomy (t-PTK) laser followed by accelerated corneal collagen crosslinking (CXL). All patients with progressive keratoconus undergoing our protocol at a London clinic between 2019 and 2023 were included. The protocol involved t-PTK at 58-μm central ablation depth at a 9-mm treatment zone on the Schwind Amaris 1050RS platform. Preoperative K readings of 43.0D (both K1 and K2) were inputted for all cases. Patients then underwent CXL with a pulsed-light accelerated protocol (30 mW/cm2 for 8 minutes of UVA exposure time with 1 second on/1 second off). Seventy-nine eyes from 55 patients were included with an average follow-up of 12 months (range 6-24 months). Both mean uncorrected distance visual acuity (UDVA) and best spectacle-corrected visual acuity improved significantly from 0.42 preoperatively to 0.29 postoperatively (P < 0.01) and 0.11 to 0.06 postoperatively (P < 0.01), respectively. The refractive cylinder reduced significantly from -3.07D to -2.63D (P < 0.05). The mean Km improved from 46.15D to 45.44D (P < 0.01) and mean Kmax from 54.03D to 52.52D (P < 0.01). 77% of eyes (n = 61) exhibited Kmax improvement postoperatively, and 56% showed an improvement in UDVA (n = 44). 16% (n = 13) had worsening of vision, but of these, only 1 patient had visual loss of more than 2 lines. No eyes had corneal haze reported at the final follow-up, and none required additional treatment. This standardized simultaneous t-PTK and CXL protocol is safe and effective for the treatment of progressive keratoconus, providing visual, refractive, and topographic improvements.

Intraocular pressure after combined photorefractive keratectomy and corneal collagen cross-linking for keratoconus

PurposeThe purpose of this prospective study was to evaluate the effect of combined photorefractive keratectomy (PRK) and corneal collagen cross-linking (CXL) on intraocular pressure (IOP) in patients with keratoconus (KC).MethodsWe included 64 eyes of 34 patients (19 males and 15 females; age: 19-40y) with stages 1–2 keratoconus which had undergone combined wavefront-optimized photorefractive keratectomy and corneal collagen cross linking. Two other groups of patients were added as controls: the PRK group including 110 eyes of 57 patients (23 males and 34 females; age: 18-44y) which had undergone wavefront-optimized photorefractive keratectomy for myopic refractive errors, and the CXL group including 36 eyes of 23 patients (14 males and 9 females; age: 12-38y) with keratoconus, not filling the inclusion criteria for combined PRK and CXL, which had undergone corneal collagen cross-linking. IOP was recorded preoperatively and postoperatively at 3, 6 and 12 months follow-up visits.ResultsPreoperative IOP in both CXL (12.1 ± 2.53 mmHg) and PRK + CXL (13.2 ± 2.50 mmHg) groups was significantly lower than PRK group (15.8 ± 3.10 mmHg) (F = 30.505, p < 0.001). At 3 months postoperatively, IOP showed no statistically significant difference between the three studied groups (F = 1.821, p = 0.164). At 6 months postoperatively, IOP in the CXL group (14.6 ± 2.64 mmHg) was significantly higher than both PRK (13.4 ± 2.27 mmHg) and PRK + CXL (13.3 ± 2.62 mmHg) groups (F = 3.721, p = 0.026). At 12 months postoperatively, IOP in the CXL group (14.3 ± 2.69 mmHg) was significantly higher than the PRK group (13.2 ± 2.23 mmHg) and was higher than PRK + CXL group (13.3 ± 2.59 mmHg) although not statistically significant (F = 3.393, p = 0.035).Regarding the percent of change from preoperative IOP, a statistically significant difference between the three studied groups was detected at 3, 6 and 12 months postoperatively (H = 117.459, 109.303, 122.694 respectively, p < 0.001). The median percent of change from preoperative IOP in the PRK group was −16.7%, −15%, and −16.7%, in the CXL group was + 14.3%, + 19.4%, and + 19.1%, while in PRK + CXL group was 0% at 3, 6 and 12 months postoperatively. (Post-hoc power analysis 75%).ConclusionsCombined PRK and CXL in patients with KC shows no significant effect on IOP, in contrast to either procedure performed separately.

Safety and Efficacy of Conventional Versus Accelerated Corneal Collagen Cross-Linking in Keratoconus and Corneal Ectatic Diseases.

Safety and Efficacy of Conventional Versus Accelerated Corneal Collagen Cross-Linking in Keratoconus and Corneal Ectatic Diseases.

Comparison of standard versus accelerated corneal collagen cross-linking for keratoconus: 5-year outcomes from the Save Sight Keratoconus Registry

ObjectiveTo compare long-term effectiveness of Standard (UV intensity: 3 mW/cm2, duration: 30 min) vs Accelerated (UV intensity: 9 mW/cm2, duration: 10 min) corneal cross-linking (CXL) for stabilising keratoconus.MethodsData for this observational study were captured through a web-based registry system from the routine clinical practice (15 sites across Australia, New Zealand and Italy). The outcomes were compared using mixed-effects regression models. A total of 100 eyes (75 patients) who had standard CXL and 76 eyes (66 patients) who had accelerated CXL, with a follow-up visit at five-year post-CXL were included.ResultsBoth CXL protocols were effective and safe in stabilising keratoconus and improving outcomes. The adjusted mean changes (95% CI) in outcomes were better in standard CXL than in accelerated CXL [visual acuity gain, 10.2 (7.9–12.5) vs 4.9 (1.6–8.2) logMAR letters; pinhole visual acuity 5.7 (3.5–7.8) vs 0.2 (−2.2 to 2.5) logMAR letters; Kmax −1.8 (−4.3 to 0.6) vs 1.2 (−1.5 to 3.9)D; K2 −0.9 (–2.2 to 0.3) vs 0.1 (−1.3 to 1.6)D; MCT –3.0 (−13.7 to 7.7) vs −11.8 (−23.9 to 0.4) µm (p values for visual acuity, pinhole visual acuity, Kmax: <0.05; for K2 and MCT: >0.05)]. The frequency of adverse events at the 5-year follow-up visit was low in both groups [standard, 5 (5%; haze 3; scarring 1, epithelial defect 1) and accelerated 3 (3.9%; haze 2, scarring 1)].ConclusionsBoth standard and accelerated CXL were safe and effective procedures for stabilising keratoconus in the long term. The standard CXL resulted in greater improvements in visual acuity and keratometry.

Visual improvement after corneal collagen cross-linking in keratoconus

This study was carried out to evaluate the effect of corneal collagen cross-linking on visual acuity, astigmatism and topographic readings (K1, K2, Kapex). : A nonrandomized noncontrolled clinical study was conducted in two tertiary eye centres in Bangladesh from July 2017 to June 2019. All attending patients diagnosed with Keratoconus were included in this study according to selection criteria. Patients with a corneal thickness of fewer than 400 microns, previous viral infection, cornea scarring, corneal opacification, severe ocular surface disease, history of immune disorders, pregnancy, and breastfeeding were excluded from the study. All selected patients underwent collagen cross-linking with Riboflavin and Ultraviolet A, followed up five days, one and six months following the procedure. Visual acuity, topographic readings (K1, K2, Kapex) and cylindrical values were assessed on every visit. The mean value of visual acuity was compared statistically with the baseline value.: A total of 30 eyes of 30 patients were studied in this study. The male-to-female ratio was 2:1. The Mean age (± SD) of the study subjects was 22.7±7.10. Before CXL, the Mean uncorrected visual acuity (UCVA) ±SD was 0.86±.35. In post-CXL follow-up time, the mean UCVA±SD was 0.46±.23 after six months of CXL. Before CXL, the Mean BCVA±SD was 0.35±.22. In post CXL era, the Mean ± SD BCVA was 0.14±.13 after six months of CXL. The Mean K1±SD was 45.66±3.43 before CXL, and the result changed after CXL. The Mean K1±SD was 43.29±3.29 after six months of CXL. The Mean K2±SD was 50.22±5.93 before CXL, and the result differed after six months of CXL. The Mean Kapex ±SD was 54.50±7.38 before CXL, and that was 51.32±6.93 after six months of CXL. Keratoconus is a bilateral non-inflammatory disorder progressively leading to vision-threatening ocular morbidity. Collagen cross-linking improves visual and topographic findings– K1, K2, and Kapex and reduces astigmatism. Early diagnosis of Keratoconus and prompt treatment will help achieve better vision.

Changes in cornea structure after corneal collagen crosslinking in keratoconus

Introduction. The article considers an objective assessment of the state of morphofunctional status of cornea in keratoconus after a corneal collagen crosslinking procedure.Aim. To assess changes in cornea structure after corneal collagen crosslinking in keratoconus. Materials and methods. The study included 24 patients: 30 eyes with KC stage I–III aged 17 to 42 years. The patients were examined before and after the corneal collagen crosslinking procedure. The postoperative follow-up period was 12 months. The patients underwent anterior segment OCT (AS-OCT) imaging to assess the demarcation line depth. The cornea and cornea nerve fibers were assessed layer-by-layer using сonfocal laser scanning microscopy, followed by the analysis of resulting confocal images through the author’s analysis algorithm.Results and discussion. The epithelialization of the cornea completed on day 3–5 after the procedure. According to OCT findings, the depth of the demarcation line averaged to 260 µm in the center and 140 µm in the periphery. The pronounced edema of the outer stroma was observed during the first-week follow-up, and a decrease in the density and apoptosis of keratocytes was noted during the first month. Over a 3–12-month postoperative follow-up period, the transient lacunar edema regressed and the density of keratocytes was restored to the baseline level. During the first three months, a pronounced disruption of the direction and structure of the cornea nerve fibres is seen.Conclusion. The crosslinking procedure results in changes in the cornea structure, one of which is appearance of the demarcation line in the stroma, which indicates the depth of penetration of the photochemical corneal collagen crosslinking process. The laser corneal confocal microscopy allows to objectively assess the depth of this effect, while the values obtained in the same follow-up periods are comparable with the findings of OCT imaging.

Posterior corneal elevation changes and characteristic analysis 1year after corneal collagen cross-linking for keratoconus.

To investigate the changes in posterior corneal elevations (PCEs) in the circular areas and local points after corneal collagen cross-linking (CXL) for the treatment of keratoconus. Method 1 divided the cornea into 0-2, 2-4, 4-6, and 6-8mm regions centering on the apex. Method 2 obtained other 34 PCE values of local point that were identified on the nasal, supra-nasal, sub-nasal, superior, inferior, temporal, supra-temporal, and sub-temporal sides of the circle with diameters of 2, 4, 6, and 8mm, and the apex and thinnest point. Method 1 showed a forward displacement of PCE at 1month after CXL and then a backward displacement at 3months. In Method 2, the points on the temporal side of 2mm and 4mm showed the same trend. The backward displacements of PCE on the temporal side of 2mm at 6months and on the temporal side of 4mm at 12months after CXL were both statistically different than those at 1month after CXL (P < 0.05). No significant forward displacement of PCE was found in all local points in different quadrants at 1year after CXL. The PCEs in circular areas and characteristic points of different diameters in keratoconic eyes after CXL change with time. Local point assessment of the PCE is more clinically significant. In points selected in different quadrants of the cornea, the change in temporal points was more significant after CXL.

Evaluating corneal changes after corneal collagen cross-linking in keratoconus by optical coherence tomography

Purpose The aim of this study was to evaluate the corneal changes after corneal collagen cross-linking (CXL) in progressive keratoconus using anterior segment optical coherence tomography. Patients and methods This prospective interventional noncomparative case-series study was conducted on 30 eyes of 18 patients of both sexes with a mean age of 23.11±4.06 years diagnosed as progressive keratoconus patients with clear central cornea. All eyes underwent epithelium-off accelerated CXL. Anterior segment optical coherence tomography and Scheimpflug camera imaging were done to all cases preoperatively and at 1, 3, and 6 months, postoperatively. Results The demarcation line (DL) was detected in all eyes 1 month postoperatively, and was still detected at 3 and 6 months, postoperatively. However, it was accurately measured until 3 months postoperatively. At 6 months, it was barely visible, so measuring its depth was difficult to be done. There was a statistically significant positive correlation between the thinnest corneal thickness and the central corneal DL depth (r=0.480, P=0.006). There was no statistically significant correlation between the maximum keratometric reading (K-max) and the depth of central corneal DL (r=−0.253, P=0.17). In addition, there was no statistically significant correlation between corneal densitometry and the depth of central corneal DL (r=−0.68, P=0.715). Conclusions The DL is a direct clinical sign of corneal CXL and can be found within 6 months after the treatment, being most clearly visible at 1 month after CXL. However, the line starts to be less visible after 3 months and becomes barely visible after 6 months postoperatively, making it difficult to measure its depth at that time.

Changes in corneal topography asymmetry indices after corneal collagen cross-linking in keratoconus

Purpose The aim of this study was to evaluate the changes in corneal topography asymmetry indices after corneal collagen cross-linking (CXL) in patients with keratoconus and to analyze their correlation with visual acuity changes and preoperative average keratometric (K) value.Setting and design This is a prospective interventional noncomparative nonrandomized study that was conducted at the Outpatient Clinic of the Ophthalmology Department of Tanta University Hospital.Patients and methods CXL was conducted in 30 eyes of 15 patients with keratoconus. Quantitative descriptors of corneal topography were measured with corneal tomography using a rotating Scheimpflug camera (Pentacam-Oculus). They included seven indices: index of surface variance (ISV), center of keratoconus index (CKI), index of height asymmetry (IHA), index of vertical asymmetry (IVA), keratoconus index (KI), index of height decentration (IHD), and minimum radius of curvature (Rmin). Follow-up of cases was done for 6 months.Results There was a statistically significant improvement in ISV (P<0.001), IVA (P<0.001), KI (P<0.001), CKI (P=0.007), IHD (P<0.001), and Rmin (P=0.001). However, there was no statistically significant difference in IHA (P=0.082). The improvement in postoperative indices was not correlated with the changes in corrected distance visual acuity. The preoperative average K value was statistically significantly positively correlated with the improvement in KI (r=0.589, P=0.001), ISV (r=0.495, P=0.005), preoperative IHD (r=0.422, P=0.020), and preoperative CKI (r=0.663, P=0.001), with a statistically significant negative correlation with the preoperative Rmin (r=−0,916, P>0.001). However, the preoperative average K value was not significantly correlated with the improvements in IHA (r=−0,078, P=0.681) and IVA (r=0.204, P=0.280).Conclusion There was a significant improvement in six of the seven topography indices 6 months after CXL. Improvement in these indices was not correlated with corrected distance visual acuity changes. The preoperative average K value was significantly correlated with the improvement in KI, ISV, preoperative IHD, preoperative CKI, and preoperative Rmin.

The short term visual, refractive and Topographic outcome of Corneal Collagen Crosslinking in Keratoconus

Background: Keratoconus is a condition characterized by biomechanical instability of cornea presenting in a progressive asymmetry and bilateral way. Corneal collagen cross-linking with riboflavin and UVA is a technique that has influenced the treatment of Keratoconus by arresting the progression. Aims and Objectives: The aim of the study was to assess the short-term efficacy and safety of collagen cross-linking in Keratoconus. Materials and Methods: This prospective, nonrandomized, interventional case study was conducted at Aravind Eye hospital and PGI, Puducherry from June 2012 to April 2013. Statistical analysis was done using repeated measures ANOVA and Bonferonn’s using IBM SPSS Inc. 20.Version. Results: A total of 30 patients were enrolled in this study and standard cross linking procedure was done. It was found that UCVA, BSCVA both improved about 40%. Spherical Equivalent reduced by 0.7 D, cylinder reduced by 0.8 D and total astigmatism decreased by about 0.4 D. Steepest K value reduced by 2 D, Irregularity and astigmatism at 3 and 5 mm also changed significantly (P&lt;0.05). Conclusion: Collagen cross-linking arrests the progression of Keratoconus. It seems to improve the UCVA and BCVA and it is a safe and effective procedure.

Changes in Ocular Higher-Order Aberrations after Corneal Collagen Cross-Linking for Keratoconus

Abstract Background: Keratoconus is a progressive, bilateral, and asymmetric non-inflammatory corneal ectasia. Corneal Col-lagen Cross-Linking (CXL) is the only treatment option that focused on disease pathology and increasing the biomechanical rigidity of the cornea. HOAs are part of the refractive errors which deteriorate the quality of the retinal image and they are not correctable with sphere and cylinder corrections. Since HOAs can impact visual performance and contrast sensitivity; they are considered important indices in the field of quality of vision. Aim of Study: To determine changes in ocular higher order aberrations (HOAs) after Corneal Collagen Cross Linking (CXL) for Keratoconus (KC). Patients and Methods: This study was conducted between April 2018 and March 2019 comprising 30 keratoconic eyes of 19 patients. Patients were treated with epithelium-off CXL and evaluated at the baseline, 3 and 6 months after the proce-dure. The ocular HOAs were measured and analyzed using Zywave II Aberrometer. Results: There was statistically significant improvement in Best Spectacle-Corrected Visual Acuity between the pre-operative and 6-month evaluations (p < 0.05). HOAs at 6mm were statistically significantly reduced at 6 months. Conclusion: CXL is effective in improving HOA param-eters in eyes with KC. changes in HOAs at 6mm were signif-icantly and strongly associated with the post-operative changes in BSCVA.

Crosslinking as a treatment option for lipid keratopathy

The purpose of this case report was to present a case of a patient treated with corneal collagen crosslinking for keratoconus with the secondary benefit of improvement of an established lipid keratopathy. After one session of crosslinking in both eyes, a marked regression of the lipid keratopathy in OS was observed in the 9th month follow-up visit. To the best of our knowledge, this is the first case report of lipid keratopathy improvement with crosslinking treatment. This can be another option when treating this condition in order to prevent visual loss and more invasive treatments.

Risk factors for progression following corneal collagen crosslinking in keratoconus.

To assess risk factors for progression following corneal collagen crosslinking (CXL) in eyes with keratoconus. Charts of patients who developed progression following conventional CXL treatment (Dresden protocol) were retrospectively evaluated in two centers (Center 1 and Center 2). 871 eyes of a total of 676 patients were analyzed. Progression was defined as > 1 diopter (D) increase in maximum keratometry (Kmax) readings compared to baseline. Progression was noted in 20 eyes of 20 patients (progression rate 3%). The mean age of the patients was 17.65 ± 5.76 (11-34)-years-old, and the mean follow-up following CXL was 36.70 ± 25.72 (12-84)-months-old. The gender distribution was 13 (65%) females and seven (35%) males. Four eyes (20%) had mild, 13 eyes (65%) had moderate, and three eyes (15%) had severe keratoconus at baseline. Fifteen eyes (75%) had allergic conjunctivitis, and 20 eyes (100%) reported eye-rubbing. Cone location was central in 17 (85%) eyes, and peripheral in 3 (15%) eyes. A mean of 2.21 ± 1.30 D (1.00-5.30 D) steepening was determined at Kmax 6 to 82months following CXL treatment. Progression rate was found to be higher in the patients under the age of 17years, female gender, allergic conjunctivitis, high preoperative Kmax (> 57 D), thin corneas (< 430µm). The majority of progressive patients were central cone and moderate keratoconus.

Precorneal tear film after corneal collagen cross-linking in keratoconus (preliminary report)

To study the condition of precorneal tear film in keratoconus patients after corneal collagen cross-linking (CXL). The study enrolled 24 patients (30 eyes) with stages I-III progressive keratoconus. All study patients underwent standard (Dresden) protocol CXL. Patients were examined before the surgery and 1 week, 1 month, and 3 months postoperatively. The condition of precorneal tear film was evaluated based on the results of Norn test (the tear film break-up time), Schirmer test, Jones test, optical coherence tomography based lacrimal meniscometry, and improved tearscopy. One month after CXL, patients with keratoconus experienced transient changes in the precorneal tear film condition - the tear film break-up time was reduced, the tear secretion was elevated, the lacrimal meniscus biometry parameters were increased, and the thickness of the tear film lipid layer was decreased. Corneal changes resulting from CXL lead to transient disorders of the mucin and lipid layers of the precorneal tear film, which requires adequate tear substitute therapy in the postoperative period.

Outcome of Corneal Collagen Cross-Linking in Keratoconus: Introducing the Predictive Factors.

Purpose:To evaluate the multiple pretreatment characteristics and topographic factors of keratoconus (KC) patients and their relationship to clinical outcomes of corneal collagen cross-linking (CXL).Methods:In this prospective study, 61 patients (106 eyes) with KC as candidates for CXL were included. Demographic data including age, sex, place of birth and residence, atopic constitution, family history, rubbing history, sleep apnea, and blood group were collected via a structured checklist. Complete ophthalmologic examination and tear collection to assess tear interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) level were performed. Topometric parameters were evaluated using a rotating Scheimpflug topography device. Changes in best corrected visual acuity (BCVA) and maximum keratometry (K-max) were considered the main predicted variables. Predictive variables were analyzed by univariate and multivariate regression.Results:The use of multivariate analysis changes in K-max was significantly associated with rubbing frequency (coefficient = 0.94, P = 0.02), blood group (coefficient = 4.52, P = 0.005), pretreatment corneal asphericity (coefficient = −3.99, P ≤ 0.001), and pretreatment central keratoconus index (CKI) (coefficient = −55.38, P = 0.001). Regarding the changes in BCVA, the multivariate analysis showed a significant association with place of birth (coefficient = −0.08, P = 0.03), pretreatment BCVA (coefficient = −0.67, P < 0.001), pretreatment central corneal thickness (CCT) (coefficient = −0.005, P = 0.04), and pretreatment keratoconus index (KI) (coefficient = 0.53, P = 0.04). Other parameters assessed in the multivariable analysis did not appear to have an individual effect on treatment outcomes.Conclusion:Our results demonstrated that blood group, rubbing of eye, place of birth, corneal asphericity, pretreatment BCVA, CKI, KI, and CCT were statistically associated with the outcome of KC following CXL.

Profile of infectious and sterile keratitis after accelerated corneal collagen cross-linking for keratoconus.

PURPOSE:The aim of this study was to assess the potential risk factors and causes of infectious and sterile keratitis after accelerated collagen cross-linking.METHODS:Case records of 968 eyes that underwent accelerated corneal collagen cross-linking (ACXL) over the period of 4 years were reviewed retrospectively. ACXL was done using (Avedro KXL® system, Waltham, MA, USA) 9 mW/cm2 for 10 min protocol providing total energy of 5.4 J/cm2.RESULTS:Of 968 eyes, a total of three eyes developed infectious keratitis and seven eyes developed sterile infiltrates. Three of this infectious keratitis had two cases which were resistant to fourth-generation fluoroquinolones. Seven cases of sterile infiltrates had excellent resolution after treatment with topical steroids. Sterile infiltrates were common in corneas with thinnest pachymetry of <400 µm, except in one case of intra stromal corneal ring segments (INTACS) + ACXL.CONCLUSION:Judicious use of steroids in the initial postoperative period is recommended so as to prevent any form of microbial keratitis. Very steep corneas and too thin corneas should be looked with high index of suspicion in view of chances of developing sterile infiltrates.

Efficacy of topical microemulsion of fatty acids of the ω-3 series on the sub-epithelial corneal nerves regeneration after epithelium-off corneal collagen cross-linking for keratoconus.

To evaluate efficacy of a microemulsion of fatty acids of the ω-3 series on the regeneration of the sub-epithelial corneal nerve plexus in patients with keratoconus after epi-off cross-linking. In this prospective study, we recruited 40 patients, 18 females, mean age 28years (range 22-37), who were randomly divided in two groups. Group A, 20 patients, after cross-linking were treated with a microemulsion of fatty acids of the ω-3 series. Group B were treated with hyaluronic acid (0.15%)-based tear substitute. Nerve tortuosity, reflectivity and density were examined with in vivo confocal microscopy. Ocular surface disease index (OSDI) questionnaire at the preoperative and at each follow-up visit (1, 3 and 6months) after treatment was completed. No significant difference between the two groups was noted at 1month in terms of nerve density and OSDI. A statistically significant difference between the two groups was detected at 3months in terms of nerve fibers density (6 ± 0.82 in Group A and 1 ± 0.51 in Group B, P = 0.0001). Reflectivity and tortuosity of the fibers did not show significant differences between the two groups at any time point. At 1month, OSDI average value in group A and in group B was 31.5 ± 1.94 and 30 ± 1.96, at 3months 13 ± 1.71 and 28 ± 1.83, and at 6months 10.5 ± 1.87 and 9.0 ± 1.81, respectively. The use of a microemulsion of fatty acids appears to ensure a faster regeneration of nerve fibers in patients undergoing epi-off cross-linking.

MyoRing Implantation in Comparison with MyoRing Implantation Combined with Corneal Collagen Crosslinking for Keratoconus

Purpose: tо estimate the effectiveness of complete corneal ring (MyoRing) implantation compared with MyoRing implantation combined with corneal collagen crosslinking (CXL) for keratoconus treatment for 36 months follow-up. Patients and Methods. There were 101 patients (124 eyes) with progressing keratoconus aged 18–59 years in the study. Intracorneal rings were implanted in all patients. The patients were divided into 2 groups. MyoRing implantation was performed in a series of 59 patients (76 eyes) with keratoconus II–III Amsler classification, 42 patients (48 eyes) had MyoRing implantation combined with CXL. Implantation of a MyoRing in the corneal pocket was performed using a PocketMaker microkeratome and corneal intrastromal implantation system. Results. Keratometry was reduced in both groups; after MyoRing implantation for 8,45 D and MyoRing combined with CXL for 7,44 D, the spherical equivalent decreased for 7,72 and 6,29 D respectively, after 36 months. The cylinder decreased to 3,33 D with MyoRing alone and to 3,11 D with MyoRing combined with CXL. The smallest corneal thickness remained stable during 36 months after the procedure. There was an improvement in uncorrected and corrected visual acuity, and the difference in the CRF within the period of up to 12 months after the operation. It can be explained by the pseudochase formation in the group with a combined procedure. Conclusion. The implantation of the MyoRing IRC and the combination of MyoRing with CXL showed efficacy and safety in stabilizing keratoconus stabilization, as well as correction of comorbided ametropia 3 years after surgery. Both MyoRing implantation and MyoRing combined with CXL were effective in the stabilization of progressive keratoconus, as well as the correction of ametropia 3 years after surgery. There was no significant difference in MyoRing implantation and its combination with corneal crosslinking in visual and refractive results. The refractive power of the cornea was only one exeption. Long follow-up and randomized prospective studies with a large number of patients are needed.