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Niazi S, del Barrio JA, Doroodgar F, Sanginabadi A, Alinia C, Hashemian SJ, Hashemi H, Alio JL. Biomechanical changes in keratoconus after customized stromal augmentation. Taiwan J Ophthalmol 2024; 14:59-69. [PMID: 38654988 PMCID: PMC11034678 DOI: 10.4103/tjo.tjo-d-23-00155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 01/01/2024] [Indexed: 04/26/2024] Open
Abstract
PURPOSE To verify corneal biomechanical changes, poststromal augmentation using myopic small-incision lenticule extraction's (SMILEs) lenticules in advanced keratoconus (KCN) through Corvis ST (Oculus, Wetzlar, Germany). MATERIALS AND METHODS A clinical trial enrolled 22 advanced KCN patients. We implanted lenticules exceeding 100 μ according to a nomogram and evaluated biomechanical factors through Corvis ST at 3-, 6-, and 24-month postimplantation. We examined parameters during the first applanation (A1), second applanation (A2), highest concavity (HC)/max concavity events, and Vinciguerra screening parameters, as recently established criteria derived from the ideal blend of diverse biomechanical and ocular factors and formulated through the application of logistic regression. Regression analyses explored relationships with age, mean keratometry value, thickness, sphere, cylinder, and best-corrected visual acuity. RESULTS Patients were well matched for age, intraocular pressure, and central corneal thickness (CCT). The mean spherical equivalent decreased from -13.48 ± 2.86 Diopters (D) to -8.59 ± 2.17 D (P < 0.007), and mean keratometry decreased from 54.68 ± 2.77 D to 51.95 ± 2.21 D (P < 0.006). Significant increases were observed in HC time (HCT), Radius-central curvature radius at the HC state-, peak distance (PD) during HC state, CCT, first applanation time, and stiffness parameter (A1T and SP-A1), whereas HC deformation amplitude, maximum deformation amplitude ratio at 2 mm, Corvis Biomechanical Index (CBI), integrated radius (IR), second applanation deformation amplitude (A2DA), first applanation velocity and deflection amplitude (A1V and A1DeflA) significantly decreased postlenticule implantation. Multivariable regression revealed age positively correlated with SP-A1 (P = 0.003) and negatively with HC delta Arc length (P = 0.007). Mean K positively correlated with CCT (P = 0.05) and negatively with CBI (P = 0.032). Best-corrected visual acuity positively correlated with HCT (P = 0.044), and the cylinder positively correlated with PD (P = 0.05) and CCT (P = 0.05) whereas negatively with IR (P = 0.025). CONCLUSIONS Stromal augmentation using myopic SMILE lenticules induces significant corneal biomechanical changes in KCN.
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Affiliation(s)
- Sana Niazi
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Negah Aref Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Farideh Doroodgar
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Negah Aref Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Azad Sanginabadi
- Department of Optometry, Iran University of Medical Sciences, Tehran, Iran
| | - Cyrus Alinia
- Department of Public Health, School of Public Health, Urmia University of Medical Sciences, Urmia, Iran
| | - Seyed Javad Hashemian
- Eye Research Center, Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Hassan Hashemi
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Jorge L. Alio
- Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain
- Vissum Miranza Alicante, Alicante, Spain
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Nasrat MM, Abdelsalam AM, Goily MB, Eldib AA, Hegazy GA. Keratometric Outcomes after Simultaneous versus Sequential Intracorneal Ring Segment Implantation with Femtosecond Laser and Corneal Collagen Crosslinking in Egyptian Patients with Keratoconus and Ectasia. J Microsc Ultrastruct 2024; 12:35-42. [PMID: 38633569 PMCID: PMC11019591 DOI: 10.4103/jmau.jmau_80_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 10/07/2021] [Indexed: 11/04/2022] Open
Abstract
Background Keratoconus (KC) is degenerative corneal disorder, with central and paracentral thinning and corneal ectasia. For KC progressive cases, primary treatment included corneal collagen cross linking (CXL) to stabilize coning and intracorneal rings segment (ICRS) to correct visual acuity. Aim The aim of the study is to assess efficacy and safety of ICRS and CXL on one session (Simultaneous) or two sessions (sequential) with maximum of 1 month apart. Patients and Methods This Prospective Intervention Comparative research made at Armed forces hospital, Cairo, Egypt from January 2017 to December 2019. Forty patients (60 eyes) with mild to moderate KC were enrolled. Patients sorted into Simultaneous group includes 21 patients (30 eyes) undergo two procedures (ICRS then CXL) at the same session and Sequential group included 19 patients (30 eyes) undergo ICRS then CXL on two sessions with month apart. Patients followed up at end of 1st, 3rd, and 6th months. Assessment included changes in corrected corneal surface irregularities as minimum keratometric 1 (K1), maximum keratometric readings (K2), and mean keratometric (Km) readings. Results Improvement of K1, K2, and Km in Simulations and Sequential groups achieved at end of 1st-, 3rd-, and 6th-month postoperative versus preoperative. Maximum improvement in Simulations and Sequential groups in K1 achieved at end of 6th and 1st months, in K2 at end of 3rd and 6th months and in Km at end of 1st and 3rd months. Conclusions Combined ICRS and CXL act safely in one or two sessions and there are no statistically significant variations between results on both methods in keratometric readings.
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Affiliation(s)
| | | | | | - Amr A Eldib
- National Institute of Laser Enhanced Science, Cairo University, Cairo, Egypt
| | - Gehan A Hegazy
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Medical Biochemistry, Medical Division, National Research Centre, Cairo, Egypt
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Thiwa D, Linke SJ, Daxer A, Steinberg J. Continuous Intracorneal Ring Implantation in Keratoconus: Efficacy, Predictive Factors, and Complications. Clin Ophthalmol 2022; 16:3055-3067. [PMID: 36160729 PMCID: PMC9491368 DOI: 10.2147/opth.s375569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/02/2022] [Indexed: 11/23/2022] Open
Abstract
Purpose To examine the clinical outcomes, predictors of visual improvement and complications of continuous intracorneal ring (ICCR) implantation in patients with keratoconus and confirmed contact-lens intolerance (CLI). Methods This nonrandomized, multi-centric, retrospective cohort study examined visual, keratometric and clinical outcomes evaluated after a minimum follow-up of 2 months. Among the inclusion criteria for the standard treatment group (STG) were corrected distance visual acuity (CDVA) <20/25 Snellen, no central corneal scars, minimum corneal thickness >350µm, and central mean keratometry reading (meanK) <55 diopters. All other eyes were classified as non-standard treatment group. Results A total of 118 eyes of 118 patients with aged 32 ± 11 years were included in this study. At a median follow-up of 161 days (interquartile range: 111-372 days) ICCR implantation improved the CDVA from a mean of 0.38 to 0.15 logMAR (p<0.0001). Our correlation analysis showed lower preoperative CDVA to be the single best predictor of CDVA improvement, with eyes of a CDVA of 20/80 or lower improving by 4.3 ± 2.0 lines on average. Eyes with a meanK >55 diopters gained 9.04±4.83 lines in UDVA and 2.86±3.09 lines in CDVA. However, postoperatively these eyes had a CDVA of 0.32±0.21 logMAR which is significantly inferior to the STG outcome (p=0.001372). Fifteen eyes (12.7%) had to undergo a ring exchange procedure because of refractive under- (9 eyes) or overcorrection (6 eyes). Two eyes (1.7%) experienced medical complications. Conclusion This study confirms the inclusion criteria of ICCR implantation in KC eyes with CDVA <20/25 and CLI. Particularly in eyes with a preoperative CDVA <20/80 and a meanK <55 diopters, ICCR implantation should be considered due to its reversibility and low rates of serious complications. The main challenge remains in the low predictability of the magnitude of this improvement in eyes with CDVA >20/30.
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Affiliation(s)
- David Thiwa
- University Medical Center Hamburg (UKE), Department of Ophthalmology, Hamburg, Germany
| | - Stephan Johannes Linke
- University Medical Center Hamburg (UKE), Department of Ophthalmology, Hamburg, Germany
- Zentrumsehstärke – Augenarztpraxis am UKE, Hamburg, Germany
| | - Albert Daxer
- International Keratoconus Center, Wels, Austria
- Medical University of Innsbruck, Department of Ophthalmology, Innsbruck, Austria
| | - Johannes Steinberg
- University Medical Center Hamburg (UKE), Department of Ophthalmology, Hamburg, Germany
- Zentrumsehstärke – Augenarztpraxis am UKE, Hamburg, Germany
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Jiménez R, Molina R, Vera J, Redondo B. The short-term effects of wearing swimming goggles on corneal biomechanics. Int Ophthalmol 2022; 42:2773-2784. [PMID: 35378638 PMCID: PMC9420087 DOI: 10.1007/s10792-022-02268-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 03/12/2022] [Indexed: 11/27/2022]
Abstract
PURPOSE This study aimed to assess the impact of wearing swimming goggles (SG) on corneal biomechanics. METHODS Corneal deformation response, central corneal thickness (CCT), intraocular pressure (IOP) and biomechanically corrected intraocular pressure (bIOP) were measured with the Corvis system (Oculus Optikgeräte GmbH, Wetzlar, Germany) in thirty-one healthy young adults while wearing a drilled SG. All measurements were obtained before, at 30 s, 2 min, 3.5 min and 5 min of wearing SG, just after SG removal and after 2 min of SG removal. RESULTS The corneal biomechanics is sensitive to SG wear, observing lower corneal deformability during SG use. Specifically, wearing SG caused an increase in the time and length of the first applanation and radius curvature at the highest concavity, as well as a decrease and in the velocity of the first applanation and time and deformation amplitude of the second applanation (p < 0.001 in all cases). After SG removal, corneal biomechanical parameters showed a rebound-effect, obtaining a higher corneal deformability in comparison with baseline reading (p-corrected < 0.05 in all cases). Additionally, IOP and bIOP significantly increased while wearing SG (p < 0.001 in both cases), whereas CCT remained stable (p = 0.850). CONCLUSIONS Wearing SG modifies the biomechanical properties of the cornea, with reduced corneal deformability during SG wear. The outcomes of this study should be taken into consideration when making clinical decisions in subjects at high risk of developing corneal ectasias or glaucoma, as well as in the post-surgical management of these ocular conditions.
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Affiliation(s)
- Raimundo Jiménez
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, University of Granada, Campus de la Fuentenueva 2, 18071, Granada, Spain
| | - Rubén Molina
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, University of Granada, Campus de la Fuentenueva 2, 18071, Granada, Spain
| | - Jesús Vera
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, University of Granada, Campus de la Fuentenueva 2, 18071, Granada, Spain.
| | - Beatriz Redondo
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, University of Granada, Campus de la Fuentenueva 2, 18071, Granada, Spain
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Vinciguerra R, Fernández-Vega-Cueto L, Poo-Lopez A, Eliasy A, Merayo-Lloves J, Elsheikh A, Madrid-Costa D, Lisa C, Alfonso JF. The Effect of Intracorneal Ring Segments Implantation for Keratoconus on In Vivo Corneal Biomechanics Assessed With the Corvis ST. J Refract Surg 2022; 38:264-269. [PMID: 35412924 DOI: 10.3928/1081597x-20220202-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the effect of the implantation of intracorneal ring segments (ICRS) in keratoconus on the dynamic corneal response (DCR) parameters obtained with the Corvis ST (Oculus Optikgeräte GmbH). METHODS This prospective clinical study included patients who underwent ICRS implantation for keratoconus over a period of 1 year. On the day of the surgery and at least 1 month after ICRS implantation, the following measurements were made: corrected and uncorrected distance visual acuity, corneal tomography indices with the Pentacam (Oculus Optikgeräte GmbH), biomechanically corrected intraocular pressure (bIOP), Corvis ST DCR parameters, integrated inverse concave radius (1/R), deformation amplitude ratio (DA ratio), stiffness parameter at first applanation (SP-A1), stress-strain index (SSI), and highest concavity radius (HRC). RESULTS Fifty-one eyes of 40 patients were included with a median follow-up time of 3 months (interquartile ratio [IQR]: 2 to 6 months). Statistical analysis showed that ICRS implantation did not affect corneal biomechanical measurements evaluated with the Corvis ST, which was demonstrated by non-significant changes in the SP-A1 (P = .637), 1/R (P = .647), HRC (P = .177), DA ratio (P = .735), and SSI (P = .501). Additionally, the results showed that bIOP measurements were not significantly affected by ICRS implantation (P = .113). CONCLUSIONS ICRS implantation does not affect corneal biomechanical measurements in early follow-up. [J Refract Surg. 2022;38(4):264-269.].
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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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