Dataset Information

Efficacy of Standard and Accelerated (10 Minutes) Corneal Crosslinking in Keratoconus Stabilization.

ABSTRACT: Purpose:To evaluate whether Accelerated CXL for 10 minutes is as effective as standard CXL for 30 minutes for the treatment of progressive keratoconus. Patients and Methods:Eighty-two eyes of 62 patients with keratometry examinations performed before and 6 months after surgery were studied. A total of 39 eyes underwent standard CXL with UVA irradiation of 3 mW/cm2 for 30 minutes and 32 eyes underwent Accelerated CXL UVA irradiation of 9 mW/cm2 for 10 minutes. The eyes of all patients had corneal thicknesses of at least 450 microns (400 microns after epithelium removal). Results:The means of the keratometry measurements in the preoperative period for the eyes subjected to standard CXL were 46.27 dioptres (D) on the flat axis (K1) and 48.93 D on the steep axis (K2). Postoperatively, K1 was 46.21 D and K2 was 48.97 D, a difference without statistical significance (p = 0.47 and p = 0.48, respectively). In the Accelerated CXL protocol, the preoperative measurements were 44.55 D and 46.19 D for K1 and K2, respectively. In the postoperative period, K1 was 43.37 D, and K2 was 46.64 D (p = 0.38 and p = 0.27, respectively). In the standard group, the mean maximum keratometry (Kmax) preoperatively was 55.87 D, with no statistical significance (p = 0.29). In the preoperative period, the Kmax of the Accelerated group was 51.15 D, with no statistical significance (p = 0.32). Conclusion:Based on the keratometry results, the accelerated protocol was as effective as the standard protocol for keratoconus stabilization.

SUBMITTER: Stock RA

PROVIDER: S-EPMC7322134 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Efficacy of Standard and Accelerated (10 Minutes) Corneal Crosslinking in Keratoconus Stabilization.

Stock Ricardo Alexandre RA Brustollin Gustavo G Mergener Rafael André RA Bonamigo Elcio Luiz EL

Clinical ophthalmology (Auckland, N.Z.) 20200624

<h4>Purpose</h4>To evaluate whether Accelerated CXL for 10 minutes is as effective as standard CXL for 30 minutes for the treatment of progressive keratoconus.<h4>Patients and methods</h4>Eighty-two eyes of 62 patients with keratometry examinations performed before and 6 months after surgery were studied. A total of 39 eyes underwent standard CXL with UVA irradiation of 3 mW/cm<sup>2</sup> for 30 minutes and 32 eyes underwent Accelerated CXL UVA irradiation of 9 mW/cm<sup>2</sup> for 10 minutes. ...[more]

PMID: 32612348

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Project description:PurposeTo assess the reliability of successive Corvis ST® measurements (CST, Oculus, Wetzlar, Germany) in keratoconus (KC) ≥ 2 years after accelerated corneal crosslinking (9 mW/cm2, 10 min, 5.4 J/cm2) compared to untreated KC corneas.MethodsThree successive CST measurements per eye were performed in ≥ 2 years after CXL (CXLG, n = 20 corneas of 16 patients) and a control group consisting of non-operated, ABC-stage-matched KC corneas according to Belin's ABCD KC grading (controls, n = 20 corneas, 20 patients). Main outcome measures included maximal keratometry (Kmax), the Belin/Ambrósio-Enhanced-Ectasia-Deviation-Index BAD-D; the biomechanical parameters A1 velocity, deformation amplitude (DA) ratio 2 mm, Ambrósio relational thickness to the horizontal profile (ARTh), integrated radius, stiffness parameter A1 (SP-A1), and the Corvis Biomechanical Factor (CBiF, the linearized term of the Corvis Biomechanical Index). Mean values, standard deviations, and Cronbach's alpha (CA) were calculated.ResultsBoth groups were tomographically comparable (BAD: 11.5 ± 4.7|11.2 ± 3.6, p = 0.682, Kmax: 60.5 ± 7.2|60.7 ± 7.7, p = 0.868 for controls|CXLG, paired t-test). A1 velocity (mean ± SD: 0.176 ± 0.02|0.183 ± 0.02, p = 0.090, CA: 0.960|0.960), DA ratio 2 mm (6.04 ± 1.13|6.14 ± 1.03, p = 0.490, CA: 0.967|0.967), integrated radius (12.08 ± 2.5|12.42 ± 1.9, p = 0.450, CA: 0.976|0.976), and CBiF (4.62 ± 0.6|4.62 ± 0.4, p = 0.830, CA: 0.965|0.965) were also comparable (controls|CXLG). ARTh was significantly higher in controls (177.1 ± 59, CA: 0.993) than after CXL (155.21 ± 65, p = 0.0062, CA: 0.993) and SP-A1 was significantly higher after CXL (59.2 ± 13, CA: 0.912) than in controls (52.2 ± 16, p = 0.0018, CA: 0.912).ConclusionARTh and SP-A1 differed significantly between controls and CXLG. Biomechanical measurements were generally of excellent reliability in both groups. CXL seems to affect biomechanical measurements of human corneas over more than 2 years.

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.

Dataset Information

Efficacy of Standard and Accelerated (10 Minutes) Corneal Crosslinking in Keratoconus Stabilization.

Publications

Efficacy of Standard and Accelerated (10 Minutes) Corneal Crosslinking in Keratoconus Stabilization.

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