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Purpose: This retrospective longitudinal study evaluated the biomechanical E-staging in KC corneas before and after intracorneal ring segment (ICRS) implantation (Intacs® SK, Addition Technology, Illinois, United States).
Methods: Biomechanical E-staging for ectatic corneal diseases was applied retrospectively on 49 KC corneas of 41 patients who underwent ICRS implantation. The main outcome parameters included the Corvis Biomechanical Factor (CBiF, the linearized Corvis Biomechanical Index and the biomechanical parameters included), the resulting biomechanical E-staging, the stress-strain index, thinnest corneal thickness (TCT), maximal anterior keratometry (Kmax), and the anterior radius of curvature (ARC). They were evaluated at 1.9 ± 1.1 months preoperatively and postoperatively after 2.8 ± 0.7, 5.8 ± 1.0, and 10.6 ± 2.3 months.
Results: The CBiF decreased (4.9 ± 0.5 | 4.7 ± 0.5, P = 0.0013), and the E-staging increased significantly (2.8 ± 0.8 | 3.1 ± 0.9, P = 0.0012, paired t-test) from preoperatively to the first postoperative follow-up. The difference remained significant after 6 months; however, there was no more difference after 11 months. TCT was stable, whereas Kmax and ARC significantly decreased after ICRS implantation (TCT: 464 ± 49, 470 ± 51, 467 ± 38, 461 ± 48; Kmax: 56.3 ± 4.5, 54.7 ± 4.5, 54.2 ± 4.8, 54.1 ± 4.3; ARC: 51.5 ± 3.4, 48.3 ± 3.8, 48.6 ± 3.0, 48.6 ± 3.2 preoperatively and 3, 6, and 11 months postoperatively, respectively). Besides Kmax and ARC, Ambrósio's relational thickness to the horizontal profile (ARTh) was the only parameter that was significantly lower than preoperatively at any follow-up (P ≤ 0.0024, Wilcoxon matched-pairs test).
Conclusion: Intacs® SK implantation results in an increasing biomechanical E-staging in the first postoperative months with stabilization near preoperative values after 1 year. Significantly lower ARTh values at any follow-up document the ICRS effect and contribute to a slightly higher postoperative biomechanical E-staging value.
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http://dx.doi.org/10.4103/IJO.IJO_2944_23 | DOI Listing |
Clin Exp Ophthalmol
August 2025
Department of Ophthalmology, Saarland University Medical Center, Homburg, Germany.
Acta Ophthalmol
August 2025
Department of Ophthalmology, Saarland University Medical Center, Homburg, Germany.
Aim: Fellow eyes (FE) of 73 keratoconus (KC) patients with acute corneal hydrops (ACH) and 130 KC patients without ACH (total 236 eyes, 110 more severely affected), serving as control groups, were retrospectively analysed to identify potential risk factors associated with the development of ACH.
Methods: Tomographic (Pentacam) and biomechanical analysis (Corvis ST, both Oculus, Germany) were performed. Tomographic parameters are as follows: K-max, thinnest corneal thickness (TCT), Belin/Ambrósio deviation (BAD-D) and the tomographic ABCDE-staging.
Curr Eye Res
June 2025
Department of Ophthalmology, Saarland University Medical Center, Homburg, Germany.
Purpose: To investigate the keratoconus characteristics and progression rate in a patient group of adolescents aged 19-24 years and to compare the results with young adults aged 25-30 years.
Methods: A total of 158 keratoconic eyes (82 and 76 eyes in the adolescent and young adult groups) of the Homburg Keratoconus Center, which were examined by Scheimpflug tomography at least two times, were included in this retrospective study. The visual characteristics, corneal tomography, and biomechanical measurements were noted at the initial visit, 6 months, 12 months, and 24 months after the initial visit.
Jpn J Ophthalmol
March 2025
Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Purpose: To determine whether corneal biomechanical parameters can predict ectasia progression.
Study Design: Retrospective observational study.
Methods: The baseline corneal biomechanical parameters of 64 eyes of 41 young patients (age, < 25 years at the first visit) who were diagnosed with keratoconus (KC) or suspected KC at Osaka University Hospital and followed up for more than two years were reviewed.
Eye Vis (Lond)
July 2024
Department of Ophthalmology, Saarland University Medical Center, Kirrberger Straße, Building 22, 66421, Homburg, Germany.
Until recently, corneal topography has been the gold standard in detecting keratectasia and monitoring its progression. The recently introduced ABCD tomographic keratoconus staging system focuses on anterior ("A") and posterior ("B") radius of curvature, thinnest corneal thickness ("C"), best-corrected visual acuity with spectacles ("D") and is supplemented with the introduction of the biomechanical E-staging (BEST, "E"). The need for biomechanical staging arose from the fact of altered biomechanical characteristics of keratectasia in comparison to healthy corneas.
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