Cross-linking For Keratoconus Research Articles

Could Automated Objective Measurements Acquired at the Preoperative Stage Estimate the Corrected Distance Visual Acuity after Corneal Cross-Linking in Keratoconus?

Objective markers describing corneal optical density (COD), thinnest corneal thickness (TCT), and anterior (ARC) and posterior (PRC) surface radii over the 3 mm thinnest region of the cornea were investigated to provide a model for estimating corrected distance visual acuity (CDVA) after corneal cross-linking (CXL) in keratoconus. CDVA, COD, TCT, ARC, and PRC were monitored (using Pentacam™) over 1 year in patients with (1) keratoconus treated with routine CXL (2) relatively stable untreated keratoconus, and (3) age/gender-matched controls. In group 1 (n = 77), the median logMAR CDVA (mode, interquartile range) improved significantly (p < 0.01) from 0.26 (0.22, 0.12-0.65) to 0.07 (0.00, 0.02-0.21). The mean (±standard deviation, 95% confidence interval) COD (in 0-100 grey scale units) in the 0-2 mm central anterior corneal region (0-2 ant), TCT (µm), ARC (mm), and PRC (mm) changed significantly (p < 0.01), from 21.2 (± 3.70, 20.4-22.0), 454 (± 40.0, 446-462), 6.49 (± 0.71, 6.33-6.65), and 4.81 (± 0.65, 4.66-4.96) to 31.5 (± 9.19, 29.5-33.6), 423 (± 49.3, 412-434), 6.78 (± 0.80, 6.60-6.98), and 4.74 (± 0.64, 4.59-4.88), respectively, but remained stable in groups 2 (n = 23) and 3 (n = 24). Significant relationships (p < 0.01) were uncovered between postop CDVA and preop values of COD, TCT, ARC, and PRC. Multilinear regression revealed significant correlations between CDVA at 1 year and preop COD, TCT, ARC, and PRC (r2 = 0.533, r20-2ant = 0.126, r2TCT = 0.321, r2ARC = 0.506, r2PRC = 0.467). Including preop CDVA further enhanced this correlation (r2 = 0.637, r2LogMAR CDVApreop = 0.566). CXL improved CDVA, increased COD and ARC, and reduced TCT and PRC. The chance of correctly estimating the CDVA at 1 year after CXL using preoperative markers of COD, TCT, ARC, and PRC is 53%, improving to 64% with the inclusion of preoperative CDVA. Objective measurements taken at the preoperative screening stage may be useful to estimate the likely postoperative CDVA when preoperative CDVA measures are unreliable or unobtainable. ClinicalTrials.gov identifier, NCT06522789.

Results of Accelerated Local Cross-Linking in Keratoconus

Objective of the study. To analyze the effectiveness of accelerated local corneal cross linking in the treatment of keratoconus (KC). Patients and methods. Thirty-four patients (42 eyes) were included in the study: 19 people (24 eyes) with stage II keratoconus, 15 people (18 eyes) with stage III Amsler keratoconus. All patients were examined using the following methods: visometry, refractokeratometry, keratotopography, optical coherence tomography of anterior segment, endothelial cell density calculation before and after surgical treatment in 6 months, 1, 2 and 3 years. Results. Significant increase of uncorrected (UDVA) and corrected (CDVA) distance visual acuity was registered 6 months after operation in KC of the II and III stages. In KC stage II, the NCOZ and EOC were greater, from 0.39 ± 0.14 to 0.61 ± 0.18 by 0.22 ± 0.04 (p &lt; 0.05) and from 0.60 ± 0.15 to 0.77 ± 0.12 by 0.17 ± 0.03 (p &lt; 0.05), respectively, in stage III. — from 0.12 ± 0.03 to 0.23 ± 0.07 by 0.12 ± 0.04 (p &lt; 0.05) and from 0.45 ± 0.10 to 0.53 ± 0.12 by 0.10 ± 0.02 (p &lt; 0.05), due to decreased refractive indices in the central 3.0 mm zone. Refractive indexes of the central corneal zone, UVA and CVA in all patients after one, two and three years, as well as data of minimal corneal thickness and endothelial cell density did not change statistically significantly during the entire observation period.

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.

Repeat corneal collagen cross-linking after failure of primary cross-linking in keratoconus

BackgroundPrimary corneal collagen cross-linking (CXL) stabilises 96% of progressive keratoconus. There is limited evidence for the treatment of choice when this fails. We present 10 years of repeat CXL and...

Combined simultaneous photorefractive keratectomy and collagen cross-linking in keratoconus suspect patients

To evaluate the safety and efficacy of combined simultaneous photorefractive keratectomy (PRK) with collagen cross-linking (CXL) in keratoconus suspects (KCS). This was a retrospective, non-randomized study of KCS patients who underwent combined simultaneous PRK with CXL. The efficacy, safety, refractive outcomes, and corneal wavefront aberration changes were assessed after the surgery and compared with existing preoperative data. Fifty-six eyes of 28 patients, including 20 females (71.4%), with a mean age of 30.92±4.09 years, were enrolled. The mean follow-up was 19.46±8.48 months (range: 7-35). At the conclusion of the study, mean uncorrected distance visual acuity LogMAR improved from 0.89±0.44 preoperatively to 0.04±0.09 postoperatively (P<0.001). In addition, a statistically significant corneal flattening was observed postoperatively, with a decrease in manifest refraction. A statistically significant increase was found in higher-order aberrations (P<0.001), horizontal coma (P<0.001), and spherical aberration (P<0.001) compared with preoperatively. Postoperatively, 41% exhibited refractive astigmatism of 0.50 diopter (D) or less; 83.8% showed 1.00 D or less. The results of our study indicate that combined simultaneous PRK with CXL can be a safe and effective method for treating refractive instability in KCS patients.

Paediatric Cross-Linking in Keratoconus: A Clinical Audit

Keratoconus is an ectasia in which progressive thinning and cone-shaped distortion of the cornea result in worsening vision through increasing myopia and astigmatism. Age at diagnosis is usually between 15 and 30 years however it has been suggested that keratoconus is often more advanced if first diagnosed in childhood and progresses more quickly. The estimated prevalence of keratoconus is 1.38 per 1000 population (2). Risk factors include family history of keratoconus, eye rubbing and atopic conditions. Patients may experience a reduction in visual acuity and distortion of the visual field. Keratoconus is diagnosed through keratometry, the measurement of the curvature, thickness and steepness of the cornea with computerised corneal topography.

Introducing a Revised Tissue Saving Protocol for Combined Topography-Guided Photorefractive Keratectomy and Cross-Linking in Keratoconic Corneas.

The aim of this study was to introduce a revised tissue-saving technique for combined topography-guided photorefractive keratectomy (PRK) and cross-linking for keratoconus (KC) treatment and to evaluate its efficacy, safety, and stability. This retrospective, noncontrolled study was performed at Maadi Eye Subspecialty Center and Eye Care Center, Cairo, Egypt. The technique was performed on virgin keratoconic corneas with 3 different morphological patterns of ectasia. It involves performing topography-guided PRK before epithelial removal, followed by customized phototherapeutic keratectomy (PTK) that is tailored to each cornea after studying the treatment profile on the laser treatment screen. The electronic medical records were explored for preoperative and postoperative data, including subjective refraction and topographic data (using Sirius topographer). The study was conducted on 123 eyes of 93 patients with a mean age of 27.98 years ±6.06. The follow-up ranged from 6 to 36 months (mean ± SD of 16.2 months ±10.4). The results showed statistically nonsignificant differences among the 3 ectasia subgroups in treatment spherical equivalent, treatment maximum depth, thickness of removed epithelium, and thinnest residual stromal bed. There were statistically significant differences in almost all values between the preoperative and postoperative data, with significant postoperative patients' improvement ( P value <0.001). The subgroups' results were almost the same as the whole cohort's results. The safety and efficacy indices of the performed procedure showed remarkably high values (1.48 ± 0.21 and 0.87 ± 0.40, respectively). This revised protocol for KC management maximally preserves stromal tissue with proven efficacy, safety, and stability.

Acute focal corneal endothelial burn: A unique early and rare complication of corneal cross-linking in keratoconus

Acute focal corneal endothelial burn: A unique early and rare complication of corneal cross-linking in keratoconus

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.

Evaluation of Dynamic Corneal Response Parameters and the Biomechanical E-Staging After Accelerated Corneal Cross-Linking in Keratoconus.

This study evaluated the biomechanical E-staging in progressive keratoconus (KC) corneas before and after epithelium-off accelerated corneal cross-linking (CXL, 9mW/cm2, 10min, 5.4J/cm2). German university-based retrospective longitudinal cohort study. The biomechanical E-staging for ectatic corneal diseases was applied retrospectively on 49 progressive KC corneas of 41 patients who underwent CXL. Main outcome parameters included the Corvis Biomechanical Factor (CBiF, the linearized Corvis Biomechanical Index), the biomechanical E-staging (E1 to E4 result of dividing the CBiF value range into 5 groups), maximal anterior keratometry (Kmax), anterior radius of curvature (ARC), and thinnest corneal thickness (TCT). They were evaluated at 2.1±2.0 months preoperatively (n=49 corneas, 41 patients) and postoperatively after 5.4±1.4, 11.3±1.8, and 23.4±1.6 months. The CBiF decreased (5.1±0.5 | 5.0±0.5, P=0.0338) and the E-staging increased significantly (2.4±0.9 | 2.6±0.8, P=0.0035) from preoperatively to the first postoperative follow-up. The difference was not significant after 11 months and there were same values after 23 months. Kmax, ARC, and TCT slightly decreased (Kmax: 56.9±6.3, 54.3±5.1, 56.2±6.6, 54.0±5.2; ARC: 49.8±3.5, 48.9±3.2, 50.8±5.6, 49.0±3.7; TCT: 470±34, 454±36, 459±35, 466±39; preoperatively and 5, 11, and 23 months postoperatively). A postoperatively decreased TCT was associated with an increased E-stage, whereas an equal or increased TCT measurement after CXL was associated with equal or lower E-staging results. The biomechanical E-staging in KC corneas is influenced by TCT measurements and increases within the first postoperative months after CXL. On the long term, it indicates a postoperative KC stabilization, with comparable E-values to preoperatively at 11 and 23 months after CXL.

Changes in retinal vessel and retinal layer thickness after cross-linking in keratoconus via swept-source OCT angiography.

To analyze the postoperative foveal avascular zone (FAZ) area, superficial capillary plexus (SCP), deep capillary plexus (DCP) vascular densities (VD), and retinal layers after cross-linking (CXL) for keratoconus treatment. Twenty-seven eyes with cross-linking treatment for keratoconus were included in the study. Foveal avascular zone (FAZ) area, SCP VD, DCP VD, and retinal layers were evaluated by using optical coherence tomography angiography (OCTA). OCTA measurements were made at preoperative, first week, and first and sixth months after the surgery. In addition, corneal topography measurements were also made. Although there was a decrease in corneal thickness in the follow-up of the patients, there was no significant difference in axial length and anterior chamber depth. There was no significant difference in full retinal thickness in the foveal and parafoveal areas. While there was a significant increase in retinal nerve fiber layer (RNFL) thickness in the foveal area (p = 0.032, p = 0.015, p = 0.017; preoperative values compared to first week, first month, and sixth month respectively), there was a decrease in ganglion cell layer (GCL) thickness in the parafoveal area in the postoperative sixth month (p = 0.028). There was no difference in FAZ measurements. In the parafoveal area, a decrease was observed in SCP VD in the sixth-month control (p = 0.019). There was a significant increase in DCP VD in the foveal area (p = 0.008, p = 0.043, p = 0.040). The preoperative mean CDVA (corrected distance visual acuity) was 0.37 ± 0.16 logMAR and postoperative sixth month mean CDVA was 0.39 ± 0.15. There was no significant difference in visual acuity(p = 0.71). Keratoconus patients successfully treated with CXL had significant changes in retinal layers and vessel density in the superficial and deep retinal plexus.

Corneal higher-order aberration changes after accelerated cross-linking for keratoconus

AimTo evaluate changes in corneal higher-order aberrations (HOAs) following epithelium-off accelerated corneal cross-linking (A-CXL) and to explore the impact on visual acuity.MethodsIn this retrospective case series, 32 eyes of 24 patients with keratoconus (KC) underwent A-CXL. Treatment was delivered at 10 mW/cm2 for 9 min with a total dose of 5.4 J/cm2. The following anterior corneal HOAs: total corneal HOAs, trefoil, secondary trefoil, coma, secondary coma, secondary astigmatism and spherical aberrations were analysed using the Scheimpflug-Placido Sirius (CSO, Italy) corneal topographer at baseline and 12 months following treatment. Multivariate analysis was used to evaluate the independent effect of HOA subtypes on changes in uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA).ResultsAt one year post CXL, UDVA and CDVA were significantly improved, -0.13 ± 0.19 LogMAR (P = 0.0005) and -0.08 ± .0.11 LogMAR (P = 0.0003), respectively. The mean preoperative trefoil, secondary trefoil, secondary coma and secondary astigmatism were 0.95 ± 0.46; µm, 0.20 ± 0.11; µm, 0.29 ± 0.19; µm and 0.42 ± 0.17 µm, respectively. At one year, the mean values decreased significantly to 0.77 ± 0.47 µm, 0.15 ± 0.11 µm, 0.25 ± 0.18 µm and 0.34 ± 0.18 µm, respectively (P < 0.05, for all). No independent relationship between any HOA changes and change in UDVA was observed. A reduction in secondary coma aberration was associated with a change in CDVA (95% CI 0.01–1.34, P = 0.048; β = 0.67).ConclusionA 9-min protocol of Accelerated corneal cross-linking is an effective treatment in improving corneal HOAs at 12 months follow up, in eyes with progressive keratoconus at one year follow-up. A change in secondary coma had a statistically significant and independent effect on CDVA.

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.

Efficacy and safety of accelerated corneal collagen cross-linking in patients with keratoconus

AIM: To study the efficacy and safety of accelerated collagen cross-linking in keratoconus. METHODS: Medical records of keratoconic corneas underwent accelerated collagen cross-linking at King Chulalongkorn Memorial Hospital, Thailand between April 2015 and August 2018 were reviewed. Preoperative and postoperative data at 1y of visual acuity, auto-refraction, corneal topography, higher-order aberrations (HOA), topometric indices and corneal densitometry were evaluated. Age of 24-30 (mean age 23.43±7.26)y, maximum keratometric value (Kmax) of 55 D, and baseline best corrected visual acuity (BCVA) of 20/40 (or 0.3 in LogMAR unit) were used as cut-off values to highlight the cross-linking effects. The effect of age, preoperative Kmax and BCVA were analyzed. The association between the change of corneal densitometry and other factors including preoperative Kmax, Kmean, manifest refraction spherical equivalent (MRSE), visual acuity, thinnest pachymetry, the change in Kmax, and the change of those parameters were also analyzed. P&lt;0.05 was considered statistically significant. RESULTS: One hundred and fifty-five patients (185 eyes) were included. Male to female ratio was 3:31. According to Amsler-Krumeich classification, stage 1 and 2 were dominant (37.84% and 35.14% respectively). At 1y, mean LogMAR uncorrected visual acuity (UCVA) improved by 0.1 (P&lt;0.05). The number of eyes of which postoperative BCVA improved more than 0.2 LogMAR was higher in the worse baseline BCVA group (preoperative BCVA ≥0.3) compared to the better baseline BCVA group (preoperative BCVA &lt;0.3) (78.26% vs 21.74%, P&lt;0.05). Mean Kmax decreased from baseline by 2.36 diopters (D) (P&lt;0.05). Seventy-three percent of the eyes of which Kmax reduced more than 2.0 D had preoperative Kmax ≥55 D. Q-value showed less prolate by 0.06 (P&lt;0.05). Corneal HOA at 6 mm from corneal apex decreased by 0.40 (P&lt;0.05). Corneal densitometry at 0-6 mm zone increased at 1mo and persisted 1y postoperatively (P&lt;0.05). The relationship of the increase in densitometric value and the decrease of thinnest pachymetry at 1y were in linear fashion. Index of surface variance, index of vertical asymmetry, keratoconus index, index of height decentration decreased at 1y (P&lt;0.05). Success rate at 1y was 90.24%. Postoperative corneal haze was found 11.35%, 30.27%, 15.67%, 10.27% and 2.16% at 1wk, 1, 3, 6mo and 1y respectively. No eyes developed corneal edema. There was one case of sterile keratitis. CONCLUSION: Accelerated collagen cross-linking in keratoconus was effective to flatten, reshape the cornea, improved visual acuity, HOA and topometric indices. Great Kmax reduction was found in advanced keratoconus. The magnitude of Kmax reduction is also greatest among previous reports.

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.

Visual and refractive effects of collagen cross-linking in keratoconus

Visual and refractive effects of collagen cross-linking in keratoconus

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.

Intraocular lens power calculation changes before and after isotonic collagen cross-linking in keratoconus patients.

Purpose:To find the intraocular lens (IOL) power calculation changes before and after isotonic collagen cross-linking (CXL) in keratoconus patients.Methods:Thirty-five eyes of 25 patients who underwent isotonic CXL were included. The cases included conventional CXL (n = 16), accelerated CXL (n = 7), contact lens-assisted CXL (CACXL) (n = 9), accelerated CACXL (n = 3). All underwent ocular biometry (IOL master), corneal topography (Orbscan II), and simulated keratometry (Orbscan II) preoperatively and 1-year post CXL. Change in best-corrected visual acuity (BCVA), axial length (AL), simulated keratometry (Sim K), anterior chamber depth (ACD), and IOL power were analyzed in the overall data and then grouped based on flattening (Group A) and no flattening (Group B) of Sim K value post CXL procedure.Results:For the overall data, there was no significant change in IOL power (P = 0.05) at the end of 1 year, BCVA showed a significant increase (P < 0.01), and Sim K reading showed a statistically significant flattening (P = 0.001); ACD and AL showed insignificant change. In intergroup comparison, there was no statistically significant change in IOL power. However, in Group A, a significant change in BCVA and Sim K values was observed. In both groups (Group A and Group B), IOL power was found to be negatively correlated with AL and Sim K values.Conclusion:Isotonic CXL did not affect IOL power calculation at the end of 1 year. However, significant change in BCVA and sim K reading was noted.

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.

Infectious keratitis after corneal crosslinking for keratoconus caused by levofloxacin-resistant microorganisms

IntroductionWe present seven cases of infectious keratitis after corneal crosslinking (CXL) to attenuate keratoconus progression.MethodsOf 524 consecutive patients who underwent CXL, 7 cases (4 males and 3 females; 21.5 ± 7.1 years) developed postoperative infectious keratitis were retrospectively reviewed. CXL was performed using the Dresden protocol or an accelerated protocol involving epithelial removal.ResultsAll cases appeared normal on the day after surgery, but subsequently developed eye pain, blurred vision, corneal infiltration, inflammation of the anterior chamber, and ciliary injection on day 2 or 3. Methicillin-resistant Staphylococcus aureus was cultured from two eyes, methicillin-sensitive Staphylococcus aureus from two eyes, and Streptococcus pneumoniae from one eye. All detected bacteria were resistant to levofloxacin (LVFX). Five of the seven cases, especially four of the five severe cases with hypopyon, had a history of atopic dermatitis. All cases were observed after 2015.ConclusionsInfectious keratitis after CXL caused by microbes resistant to LVFX is increasing. In addition to careful postoperative observation of the cornea, preoperative evaluation of bacteria within the conjunctival sac evident on nasal swab cultures may be useful to identify potentially problematic microbes and inform the selection of appropriate antibiotics.