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Feld S, Flockerzi E, Daas L, Xanthopoulou K, Sideroudi H, Langenbucher A, Seitz B. [Corneal biomechanics before and after cross-linking in patients with keratoconus]. DIE OPHTHALMOLOGIE 2023; 120:940-946. [PMID: 37043004 DOI: 10.1007/s00347-023-01839-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 02/10/2023] [Accepted: 03/01/2023] [Indexed: 04/13/2023]
Abstract
OBJECTIVE The aim of this study was to analyze the effect of corneal cross-linking (CXL) on corneal biomechanics and visual acuity. PATIENTS AND METHODS The examination results before and after CXL in 56 eyes of 56 patients between 2017 and 2021 were evaluated retrospectively. The last preoperative examination was compared to the postoperative follow-up values after 6 and 12 months. The main outcome measures included various biomechanical parameters from the Corvis ST (CST), Pentacam and the visual acuity (logMAR, "logarithm of the Minimal Angle of Resolution"). For longitudinal evaluation, a general linear model for repeated measurements was used. A p-value of less than 0.05 was considered to show a statistically significant result. Bonferroni correction was applied for multiple comparisons. RESULTS The maximum corneal refractive power Kmax decreased slightly without statistical significance from 57.1 ± 6.1 diopters (dpt) to 56.6 ± 6.3 dpt after 6 months (p = 0.076) and 56.8 ± 6.6 dpt after 12 months (p = 0.443). The Pentacam parameter Belin/Ambrósio Enhanced Ectasia Total Deviation Display (BAD D) showed a statistically significant increase from the preoperative value of 8.4 ± 3.7 to the postoperative value of 9.1 ± 3.6 after 6 months (p < 0.001) and to 8.9 ± 3.5 after 12 months (p = 0.051). The CST parameter Ambrósio's relational thickness to horizontal profile (ARTh) decreased statistically significantly from 229.9 ± 109.6 to 204.8 ± 84.9 at 6 months (p = 0.017) and 205.3 ± 93.7 at 12 months (p = 0.022). The CST parameter stiffness parameter A1 (SP A1) increased slightly from the preoperative value 69.9 ± 17.2 to 70.4 ± 17.2 after 6 months (p = 1) and 71 ± 18.2 after 1 year (p = 1). Mean best-corrected visual acuity (logMAR) showed an improvement from 0.39 ± 0.3 to 0.34 ± 0.3 at 6 months (p = 0.286) and to 0.31 ± 0.3 at 12 months (p = 0.077). Regarding the ABCD classification, the parameters were determined preoperatively with an average of A2B3C1D2. They showed the same value of A2B3C1D2 after 6 and 12 months. CONCLUSION In progressive keratoconus, corneal cross-linking has the potential to positively influence the biomechanics of the cornea and visual acuity as a low complication treatment option.
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Affiliation(s)
- S Feld
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrberger Str. 100, 66424, Homburg/Saar, Deutschland.
| | - E Flockerzi
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrberger Str. 100, 66424, Homburg/Saar, Deutschland
| | - L Daas
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrberger Str. 100, 66424, Homburg/Saar, Deutschland
| | - K Xanthopoulou
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrberger Str. 100, 66424, Homburg/Saar, Deutschland
| | - H Sideroudi
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrberger Str. 100, 66424, Homburg/Saar, Deutschland
| | - A Langenbucher
- Institut für Experimentelle Ophthalmologie, Universität des Saarlandes, Homburg/Saar, Deutschland
| | - B Seitz
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrberger Str. 100, 66424, Homburg/Saar, Deutschland
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Pedrotti E, Bonacci E, Fasolo A, Longo R, Pastore G, Vinciguerra R, Vinciguerra P, Marchini G. Corneal Biomechanical Evaluation After Meniscus-Shaped Stromal Lenticule Addition Keratoplasty (MS-SLAK) for Keratoconus. J Refract Surg 2023; 39:499-504. [PMID: 37449508 DOI: 10.3928/1081597x-20230523-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
PURPOSE To evaluate corneal biomechanical changes after meniscus-shaped stromal lenticule addition keratoplasty (MS-SLAK) performed for the treatment of keratoconus. METHODS This interventional study included patients affected by advanced keratoconus (stage III and IV) who underwent examination with a dynamic Scheimpflug analyzer and non-contact tonometer (Corvis ST; Oculus Optikgeräte GmbH) at baseline and 12 months after MS-SLAK. The biomechanical parameters evaluated in this study were integrated inverse radius (1/R), deformation amplitude ratio (DA ratio), stiffness parameter at first applanation (SP-A1), biomechanical intraocular pressure (bIOP), central corneal thickness (CCT), and stress-strain index (SSI). RESULTS Sixteen patients were enrolled in the study. The analysis was ultimately conducted on 15 patients. Comparative analyses showed an increase in corneal stiffness as demonstrated by a rise in SSI (P < .0001) and SP-A1 (P < .0001) and a decrease in DA ratio (P < .0001) and 1/R (P = .01). A significant increase in CCT was found (P < .0001). No statistically significant modification was found for bIOP (P = .43). CONCLUSIONS The corneal biomechanical analyses evaluated by the Corvis ST showed that MS-SLAK for advanced keratoconus is able to increase corneal overall stiffness. This result is explained by the significant increase in thickness induced by MS-SLAK. [J Refract Surg. 2023;39(7):499-504.].
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Reliability analysis of successive Corvis ST® measurements in keratoconus 2 years after accelerated corneal crosslinking compared to untreated keratoconus corneas. Graefes Arch Clin Exp Ophthalmol 2022; 261:1055-1061. [PMID: 36305911 PMCID: PMC10049946 DOI: 10.1007/s00417-022-05881-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 10/12/2022] [Accepted: 10/20/2022] [Indexed: 11/04/2022] Open
Abstract
Abstract
Purpose
To 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.
Methods
Three 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.
Results
Both 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).
Conclusion
ARTh 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.
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Hamid A, Jahadi-Hosseini H, Khalili MR, Jahanbani-Ardakani H. Corneal Biomechanical Changes after Corneal Cross-Linking in Patients with Keratoconus. J Curr Ophthalmol 2022; 34:409-413. [PMID: 37180532 PMCID: PMC10170983 DOI: 10.4103/joco.joco_177_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 06/17/2022] [Accepted: 08/07/2023] [Indexed: 05/16/2023] Open
Abstract
Purpose To evaluate the changes in biomechanical properties of the cornea using the Corvis ST device after the treatment of keratoconus patients with ultraviolet-A/riboflavin corneal cross-linking (CXL). Methods Thirty-seven eyes from 37 consecutive patients with progressive keratoconus were included in this prospective observational case series. Corneal biomechanical parameters including the length of the applanated cornea (L1 and L2), corneal movement velocity during applanation (V1 and V2) at the moment of the first and second applanation, deformation amplitude (DA), distance between bending points of the cornea points of the cornea (PD), and concave radius of curvature (R) at the point of the highest concavity were recorded using the Corvis ST at baseline, 3 months, and 1 year after CXL. Results The mean age of the patients was 23.27 years (range, 19-31 years). Among CorVis ST corneal biomechanical parameters, L1, DA, PD, and R at the point of the highest concavity did not change significantly. The length of the applanated cornea at the moment of second applanation (L2) showed a significant change 3 months after CXL, but no significant difference was found between the 3-month and 1-year values of this parameter. Corneal movement velocity during applanation (V1 and V2) did not change 3 months after doing CXL, but the changes in these parameters were significant 1 year after CXL. Conclusions Although the CorVis ST device may detect changes in some biomechanical properties of cornea after the treatment of keratoconus patients with CXL, many parameters remain unchanged, and this device cannot readily be used to find the effects of CXL.
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Affiliation(s)
- Adel Hamid
- Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hamidreza Jahadi-Hosseini
- Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Reza Khalili
- Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hamidreza Jahanbani-Ardakani
- Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
- Address for correspondence: Hamidreza Jahanbani-Ardakani, Poostchi Ophthalmology Research Center, Zand Street, Shiraz University of Medical Sciences, Shiraz, Iran. E-mail:
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Padmanabhan P, Lopes BT, Eliasy A, Abass A, Elsheikh A. In vivo biomechanical changes associated with Keratoconus progression. Curr Eye Res 2022; 47:982-986. [PMID: 35385372 DOI: 10.1080/02713683.2022.2058020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Purpose: To assess the biomechanical deterioration arising from keratoconus progression in-vivo.Materials and Methods: The preoperative examinations of 32 progressive KC cases that were submitted to corneal cross-linking were evaluated. The examinations included the corneal tomography using the Pentacam HR and biomechanical parameters assessed by the Corvis ST (Oculus, Wetzlar, Germany). The results were recorded at two time points, the latter of which was at the last visit before the CXL procedure. Keratoconus progression was characterised by a significant change in the ABCD system.Results: At the last follow-up visit (41.4 ± 40.9 months) all morphological parameters of the ABCD grading system showed significant deterioration (p < 0.001). The comparative analyses revealed a significant reduction in corneal stiffness expressed by a significant reduction in the stress-strain index (SSI: -0.10 ± 0.06, p < 0.001), the Stiffness parameter A1 (SP-A1: -6.1 ± 12.0 mmHg/mm, p = 0.011), by a significant increase in the integrated Inverse Radius (IIR: 0.95 ± 1.04 mm-1, p < 0.001) and in the deflection amplitude (DA) ratio (0.23 ± 0.58, p = 0.034). A barely significant increase in the DA also pointed towards corneal stiffness reduction. (0.04 ± 0.13 mm, p = 0.056). The SSI and the IIR were the indices with the smallest overlaps between the two examinations.Conclusions: It has been demonstrated in-vivo that corneal biomechanical deterioration occurs with keratoconus progression. The larger changes observed in the SSI and the IIR when compared to the remaining biomechanical parameters suggests that these parameters could be suitable to assess the corneal stiffness reduction in keratoconus natural progression.
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Affiliation(s)
- Prema Padmanabhan
- Department of Cornea and Refractive Surgery, Sankara Nethralaya, Chennai, India
| | - Bernardo T Lopes
- School of Engineering, University of Liverpool, Liverpool, UK.,Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Ashkan Eliasy
- School of Engineering, University of Liverpool, Liverpool, UK
| | - Ahmed Abass
- School of Engineering, University of Liverpool, Liverpool, UK.,Department of Production Engineering and Mechanical Design, Faculty of Engineering, Port Said University, Egypt
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool, UK.,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China.,National Institute for Health Research (NIHR) Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
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Li M, Yu T, Gao X, Wu XY. Accelerated corneal collagen cross-linking in clinical management of infectious keratitis. J Int Med Res 2021; 48:300060520926411. [PMID: 32589855 PMCID: PMC7436827 DOI: 10.1177/0300060520926411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective To evaluate the clinical efficacy of corneal collagen cross-linking (CXL) in the treatment of infectious corneal diseases. Methods This study retrospectively analyzed the clinical efficacy of CXL in 65 eyes with infectious keratitis in Jinan Second People’s Hospital from December 2016 to June 2018. During 6 months of follow-up after CXL treatment, the results of confocal microscopy and anterior segment optical coherence tomography, as well as visual acuity and corneal biomechanical parameters, were recorded in detail. Results In general, the overall cure rate was 93.85%; no corneal endothelial dysfunction was encountered in any patients. After 6 months of follow-up, the visual acuity of cured patients was significantly enhanced, while corneal thickness was significantly reduced. Hyphae growth of patients with fungal keratitis was completely inhibited at 1 month postoperatively. Furthermore, corneal biomechanical parameters (i.e., central corneal thickness, deformation amplitude, and pachymetry intraocular pressure) were significantly improved after surgery, compared with baseline measurements. Conclusion Accelerated CXL may be an effective adjuvant treatment for infectious keratitis.
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Affiliation(s)
- Miao Li
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, P.R. China
- Department of Ophthalmology, Jinan Second People’s Hospital, Jinan, P.R. China
| | - Tao Yu
- Department of Ophthalmology, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, P.R. China
| | - Xin Gao
- Department of Ophthalmology, Jinan Second People’s Hospital, Jinan, P.R. China
| | - Xin-Yi Wu
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, P.R. China
- Xin-Yi Wu, Department of Ophthalmology, Qilu Hospital of Shandong University, No. 107 Wenhua xi lu, Jinan, Shandong 250011, P.R. China.
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Yoshida J, Toyono T, Shirakawa R, Miyai T, Usui T. Risk factors and evaluation of keratoconus progression after penetrating keratoplasty with anterior segment optical coherence tomography. Sci Rep 2020; 10:18594. [PMID: 33122764 PMCID: PMC7596038 DOI: 10.1038/s41598-020-75412-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 10/14/2020] [Indexed: 11/09/2022] Open
Abstract
To determine the risk factors and unique characteristics of keratoconus (KC) progression after penetrating keratoplasty (PK), anterior segment optical coherence tomography parameters were statistically analyzed in comparison with eyes undergoing PK for other diseases as a control. Ninety-one eyes maintaining clear PK grafts for over 10 years were divided into 2 groups according to the primary indication for PK (KC vs Others groups). Corneal thinning indicators (inferior host thinnest corneal thickness/central corneal thickness [IHT/CCT], inferior graft thinnest corneal thickness/CCT [IGT/CCT]), were smaller whereas anterior chamber depth, and steepest corneal power (Ks), and maximum corneal power (Kmax) were larger in the KC group with statistical significance. Graft size, Kmax and Ks correlated with IHT/CCT and IGT/CCT in the KC group. These correlations were not detected in controls. Graft size and postoperative period were selected by multivariate regression analysis as factors for corneal ectatic changes in the KC group. In conclusion, KC eyes long after PK show inferior graft and host corneal thinning, and corneal protrusion. Corneal power parameters such as Kmax or Ks can be used to monitor KC progression after PK. A small graft might lead to KC progression after PK.
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Affiliation(s)
- Junko Yoshida
- Department of Ophthalmology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. .,Department of Ophthalmology, The International University of Health and Welfare, 1-4-3, Mita, Minato-ku, Tokyo, 108-8329, Japan.
| | - Tetsuya Toyono
- Department of Ophthalmology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Rika Shirakawa
- Department of Ophthalmology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Takashi Miyai
- Department of Ophthalmology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Tomohiko Usui
- Department of Ophthalmology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.,Department of Ophthalmology, The International University of Health and Welfare, 1-4-3, Mita, Minato-ku, Tokyo, 108-8329, Japan
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Intracorneal Stromal Ring Can Affect the Biomechanics of Ectatic Cornea. J Ophthalmol 2020; 2020:4274037. [PMID: 33083047 PMCID: PMC7563082 DOI: 10.1155/2020/4274037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 07/27/2020] [Accepted: 08/04/2020] [Indexed: 11/17/2022] Open
Abstract
Purpose The biomechanical properties of ecstatic cornea undergo changes. This study evaluates the biomechanical changes of ecstatic cornea after implantation of two types of intracorneal stromal ring (ICR). Methods For doing this prospective cross-sectional study, 32 patients with keratoconus (KCN) were randomly divided into two 16-member groups (group I: MyoRing, group II: KeraRing). The main inclusion criteria were transparent cornea with no scar in the central part, corneal thickness >450 µ in the incision region, keratometry within 48–52 diopters, and progressive course of corneal thinning. Biomechanics of the cornea was evaluated by “ORA” and “Corvis” devices. All of the data were recorded and analyzed before implantation of the rings and 6 months thereafter. Results The mean ages of patients of groups I and II were 26 ± 6.55 and 33.86 ± 8.5, respectively. The postoperative change of sphere refraction was significant in both groups. However, reduction in the astigmatism was significant only in group I. In addition, the change of flat meridian keratometry (Kf) was significant before and after ring implantation in group I, unlike group II. The changes in CH and CRF parameters (ORA) were not significant in either group before and after the operation. Besides, only HRC parameter (Corvis) decreased significantly in both groups before and after the operation. Conclusion Both MyoRing and KeraRings have positive effects on the biomechanics of cornea at least during the first year after implantation. Comparison of these two types of ICR did not show significant differences in Corvis and ORA parameters.
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