Corneal Collagen Crosslinking Treatment in a Case with Pneumococcal Keratitis.
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ABSTRACT:
SUBMITTER: Bozkurt Oflaz A
PROVIDER: S-EPMC5468530 | biostudies-other | 2017 Jun
REPOSITORIES: biostudies-other
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Project description:PURPOSE: To assess the effects of preoperative patient characteristics on clinical outcomes of corneal crosslinking (CXL) treatment in patients with progressive keratoconus. METHODS: This retrospective study comprised 96 eyes of 96 patients who had unilateral CXL treatment for progressive keratoconus. All patients underwent a complete ophthalmological examination and corneal topography at baseline and 1 year. Subgroup analyses were performed according to the age (<30 and ≥ 30 years), gender, preoperative corrected distance visual acuity (CDVA, <0.3 and ≥ 0.3 logMAR (log of the minimum angle of resolution)), preoperative maximum keratometry (K, <54 and ≥ 54 D), baseline topographic cone location (central, paracentral, and peripheral), and preoperative thinnest pachymetry (<450 and ≥ 450 μm) to determine the associations between preoperative patient characteristics and outcomes (changes in visual acuity and maximum keratometry) of CXL treatment. RESULTS: In the entire study population, mean CDVA and maximum K significantly improved after CXL treatment (P<0.001). Patients with a preoperative CDVA of 20/40 Snellen equivalent or worse (≥ 0.3 logMAR) experienced more visual improvement after CXL treatment (P<0.001). However, an age ≥ 30 years and a baseline thinnest pachymetry less than 450 μm were found significantly associated with more flattening in maximum keratometry (P=0.024, P=0.005 respectively). Gender, preoperative maximum K, and baseline topographic cone location did not show significant effect on postoperative visual acuity and maximum keratometry (P>0.05). CONCLUSIONS: In patients with progressive keratoconus, age, baseline visual acuity, and baseline thinnest pachymetry seem to affect the success of the CXL treatment.
| S-EPMC3890756 | biostudies-other
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| S-EPMC7389372 | biostudies-literature
Project description:To compare the results of standard corneal crosslinking (CXL) and transepithelial iontophoresis-assisted CXL after 24 months follow-up.Corneal crosslinking (CXL) was performed in a series of 149 eyes of 119 patients with keratoconus I-II of Amsler classification. Depending on the CXL method, patients were divided into two groups: (1) 73 eyes with standard CXL and (2) 76 eyes with transepithelial iontophoresis-assisted CXL. Depending on the group, epithelium removal or administration of riboflavin solution by iontophoresis for 10 min was performed, after which standard surface UVA irradiation (370 nm, 3 mW/cm2 ) was performed at a 5-cm distance for 30 min.A statistically significant difference in corrected distance visual acuity (CDVA) was observed between the two groups, with a better outcome in the second group after 6 months (p = 0.037); however, no significant difference was found 24 months after treatment (p = 0.829). Stabilization and regression of keratometry values were achieved in both groups, but standard CXL was more effective. The average demarcation line depth in the standard CXL group was 292 ± 14 ?m after 14 days and 172 ± 16 ?m in the transepithelial iontophoresis-assisted CXL group. No demarcation line was detected after 1 month and 3 months in 45% and 100% of the eyes in the second group respectively.Transepithelial iontophoresis-assisted collagen crosslinking showed to be less effective than standard CXL after 24 months of follow-up, possibly due to a more superficial formation of corneal collagen crosslinks, however the stopping of disease progression was achieved 24 months after procedure.
| S-EPMC5111766 | biostudies-literature
Project description:PurposeTo describe a case of rapid keratitis and corneal perforation after epithelium off collagen cross-linking.ObservationsWe report a case of a 17-year-old male who underwent collagen cross-linking with the protocol and device approved by the United States Food and Drug Administration (FDA) that developed a corneal infiltrate 3 days after the procedure. He later developed corneal thinning and perforation on day 5 requiring the use of cyanoacrylate glue and a Kontur lens. Despite initial improvement in the infiltrate with fortified antibiotics he later had leakage of aqueous around the glue and a flat chamber requiring an emergent penetrating keratoplasty on postoperative day 16.Conclusion and importanceWhile collagen cross-linking has been very effective for treating keratoconus and is being recommended more frequently since FDA approval in the United States, severe complications such as corneal perforation requiring early transplant can still occur.
| S-EPMC7132167 | biostudies-literature
Project description:PURPOSE:To assess the clinical efficacy of sequential intrastromal corneal ring segment (ICRS) implantation and corneal crosslinking (CXL) in corneal ectasia. METHODS:This retrospective case series included eight eyes in which both ICRS implantation and CXL had been performed. CXL was performed within 1 month after ICRS implantation. The clinical outcomes (visual acuity, refractive errors, keratometry, and topographic indices) of these patients were compared with those of patients who had undergone only ICRS implantation (eight eyes) or CXL (20 eyes). RESULTS:Greater improvement in uncorrected visual acuity was observed in the ICRS + CXL group than in the ICRS or CXL alone groups at both 6 (p = 0.008) and 12 months (p = 0.028). Refractive errors of sphere and spherical equivalent were significantly reduced in both the ICRS (p = 0.002 at 6 months, p = 0.004 at 12 months) and ICRS + CXL groups (p < 0.001 at both 6 and 12 months). Keratometric values including the maximum, minimum, and average were significantly reduced in all 3 groups at postoperative 6 and 12 months; however, the greatest reductions were observed in the ICRS + CXL group (all p < 0.001). CONCLUSIONS:ICRS implantation followed by CXL within 1 month seems to be effective, and may be superior to ICRS or CXL alone in improving visual acuity and reducing refractive errors and keratometric values.
| S-EPMC6911792 | biostudies-literature
Project description:PurposeTo investigate patient risk factors and to look for potential causes of sterile infiltrates following an unexpected cluster of sterile keratitis after a routine collagen cross-linking (CXL) list.MethodsThe records of all 148 cases of CXL were reviewed retrospectively. The equipment and solutions used and our clinic's standard operating procedure for CXL were reviewed. An in-vitro experiment to explore the variation in ultraviolet A (UVA) irradiance from fluctuations in the working distance of the UVA lamp was conducted.ResultsThe four patients who developed sterile infiltrates had steeper maximum corneal curvatures (68.0±7.3?D) and thinner pachymetry (389.9±49.0??m) than the 144 who did not (57.0±8.2?D, P=0.05; 454.6±45.4??m, P=0.08). A corneal curvature of >60?Dand a pachymetry of <425??m were significant risk factors. All four affected cases obtained a complete resolution with topical antibiotics and steroids. The unaided VA and the maximum K improved from their pre-operative levels in three out of four patients. A 2-mm reduction in distance of the VEGA C.B.M. X-Linker from a treated surface increased irradiance to 3.5-3.7?mW/cm(2), which is above the threshold for endothelial toxicity.ConclusionPatients with thinner and steeper corneas are at an increased risk of developing sterile keratitis. The visual outcomes despite this complication are good.
| S-EPMC4274277 | biostudies-literature
Project description:Corneal collagen cross-linking (CXL) halts human corneal ectasias progression by increasing stromal mechanical stiffness. Although some reports describe that this procedure is effective in dealing with some infectious and immunologic corneal thinning diseases, there is a need for more animal models whose corneal thickness more closely resemble those occurring in these patients. To meet this need, we describe here high-intensity protocols that are safe and effective for obtaining CXL in rat corneas. Initially, a range of potentially effective UVA doses were evaluated based on their effectiveness in increasing tissue enzymatic resistance to dissolution. At UVA doses higher than a threshold level of 0.54 J/cm2, resistance to enzymatic digestion increased relative to that in non-irradiated corneas. Based on the theoretical threshold CXL dose, a CXL regimen was established in which the UVA tissue irradiance was 9 mW/cm2, which was delivered at doses of either 2.16, 2.7 or 3.24 J/cm2. Their dose dependent effects were evaluated on ocular surface morphological integrity, keratocyte apoptotic frequency, tissue thickness and endothelial cell layer density. Doses of 2.16 and 2.7 J/cm2 transiently decreased normal corneal transparency and increased thickness. These effects were fully reversed after 14 days. In contrast, 3.24 J/cm2 had more irreversible side effects. Three days after treatment, apoptotic frequency in the CXL-2.16 group was lower than that at higher doses. Endothelial cell losses remained evident only in the CXL-3.24 group at 42 days posttreatment. Stromal fiber thickening was evident in all the CXL-treated groups. We determined both the threshold UVA dose using the high-intensity CXL procedure and identified an effective dose range that provides optimal CXL with minimal transient side effects in the rat cornea. These results may help to provide insight into how to improve the CXL outcome in patients afflicted with a severe corneal thinning disease.
| S-EPMC5482453 | biostudies-literature
Project description:This review aims to assess the efficacy and safety of epithelial removal (ER) and transepithelial (TE) corneal collagen crosslinking (CXL) for the treatment of keratoconus. We used MEDLINE to identify all ER and TE CXL studies on keratoconic eyes (n≥20, follow-up ≥12 months). Ex vivo and studies for non-keratoconus indications or in conjunction with other procedures were excluded. Data on uncorrected (UDVA) and corrected (CDVA) distance visual acuity, refractive cylinder, maximum keratometry (Kmax), and adverse events were collected at the latest follow-up and 1 year. Only one randomised controlled trial (RCT) qualified inclusion. Forty-four ER and five TE studies were included. For logMAR UDVA, CDVA, mean spherical equivalent, refractive cylinder and Kmax, at latest follow-up 81, 85, 93, 62, and 93% ER studies vs 66.7, 80, 75, 33, and 40% TE studies reported improvement, respectively. Whereas at 1 year, 90, 59, and 91% ER studies vs 80, 50, and 25% TE studies reported improvement, respectively. The majority of studies showed reduced pachymetry in both groups. Treatment failure, retreatment rates, and conversion to transplantation were reported to be up to 33, 8.6, and 6.25%, respectively, in ER studies only. Stromal oedema, haze, keratitis, and scarring were only reported in ER studies, whereas endothelial cell counts remained variable in both groups. Both ER and TE studies showed improvement in visual acuity, refractive cylinder but Kmax worsened in most TE studies. Adverse events were reported more with ER studies. This review calls for more high quality ER and TE studies with comparable parameters for further assessment of safety and efficacy.
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Project description:Corneal collagen crosslinking with riboflavin photosensitization and ultraviolet irradiation is a novel approach to limiting the progression of keratoconus in patients by increasing the elastic modulus of the degenerate cornea. Beneficial reductions in corneal steepness and aberrations after crosslinking also frequently occur. In a previous study, we described a computational modeling approach to simulating topographic progression in keratoconus and regression of disease with corneal collagen crosslinking. In the current study, this model has been expanded and applied to the inverse problem of estimating longitudinal time-dependent changes in the corneal elastic modulus after crosslinking using in vivo measurements from 16 human eyes. Topography measured before crosslinking was used to construct a patient-specific finite element model with assumed hyperelastic properties. Then the properties of the cornea were altered using an inverse optimization method to minimize the difference between the model-predicted and in vivo corneal shape after crosslinking. Effects of assumptions regarding sclera-to-cornea elastic modulus ratio and spatial attenuation of treatment effect due to ultraviolet beam characteristics on the predicted change in elastic modulus were also investigated. Corneal property changes computed by inverse finite element analysis provided excellent geometric agreement with clinical topography measurements in patient eyes post-crosslinking. Over all post-treatment time points, the estimated increase in corneal elastic modulus was 110.8 ± 48.1%, and slightly less stiffening was required to produce the same amount of corneal topographic regression of disease when the sclera-to-cornea modulus ratio was increased. Including the effect of beam attenuation resulted in greater estimates of stiffening in the anterior cornea. Corneal shape responses to crosslinking varied considerably and emphasize the importance of a patient-specific approach.
| S-EPMC4104483 | biostudies-literature
Project description:This study aimed to quantify the changes in corneal higher-order aberrations (HOAs) before and after treatment for infectious keratitis and verify the correlation between corneal HOAs and visual acuity. Corneal HOAs were analysed using swept-source anterior segment optical coherence tomography (AS-OCT). Ninety-eight eyes of 96 consecutive patients with infectious keratitis treated with topical eye drops were retrospectively evaluated. Corneal HOAs increased with the infection but decreased with infection resolution following antimicrobial treatment. Corneal HOAs became larger as the degree of corneal findings became more severe. The increase in HOAs of the total cornea was correlated with the decrease in visual acuity both before and after treatment (4 mm, ρ = 0.530 and 0.590; 6 mm, ρ = 0.479 and 0.567, respectively; all P < 0.0001). Furthermore, pretreatment HOA (anterior, 6 mm), pretreatment logMAR best spectacle-corrected visual acuity, and age were prognostic factors significantly associated with posttreatment visual acuity (β = 0.31, P = 0.013; β = 0.36, P < 0.0001; and β = 0.35, P = 0.0007, respectively) (adjusted R2 = 0.474). These results indicate that corneal HOAs quantified using AS-OCT can be used as an objective index to evaluate corneal optical function during the treatment of infectious keratitis.
| S-EPMC9842715 | biostudies-literature