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Wilson SE, Dupps WJ. Salzmann's Nodular Degeneration in Refractive Surgery: The Earlier Hit Hypothesis of EBM Injury-Related Fibrosis of the Subepithelial Space and Deeper Corneal Extension. J Refract Surg 2024; 40:e279-e290. [PMID: 38717084 DOI: 10.3928/1081597x-20240322-02] [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: 06/30/2024]
Abstract
PURPOSE To review the atypical development of Salzmann's nodular degeneration (SND) after two cases of laser in situ keratomileusis (LASIK) and one case of photorefractive keratomileusis (PRK), and to highlight the pathophysiology of SND and its treatment. METHODS Three cases of SND (two following LASIK performed with microkeratomes and one following PRK) were reviewed and Pubmed.gov and internet searches were performed. RESULTS SND is myofibroblast-generated fibrosis in the subepithelial space between the epithelium and Bowman's layer that develops years or decades after traumatic, surgical, infectious, or inflammatory injuries to the cornea in which the epithelial basement membrane is damaged in one or more locations and does not fully regenerate. It is hypothesized based on these cases, and the previous immunohistochemistry of other investigators, that myofibroblast precursors, such as fibrocytes or corneal fibroblasts, that enter the subepithelial space are driven to develop into myofibroblasts, which slowly proliferate and extend the fibrosis, by transforming growth factor-beta from epithelium and tears that passes through the defective epithelial basement membrane. These myofibroblasts and the disordered collagens, and other extracellular matrix components they produce, make up the subepithelial opacity characteristic of SND. Nodules are larger accumulations of myofibroblasts and disordered extracellular matrix. If the injury is associated with damage to the underlying Bowman's layer and stroma, as in LASIK flap generation, then the myofibroblasts and fibrosis can extend into Bowman's layer and the underlying anterior stroma. CONCLUSIONS SND fibrosis often extends into Bowman's layer and the anterior stroma if there are associated Bowman's defects, such as incisions or lacerations. In the latter cases, SND frequently cannot be removed by simple scrape and peel, as typically performed for most common SND cases, but can be trimmed to remove the offending tissue. This condition is more accurately termed Salzmann's subepithelial fibrosis. [J Refract Surg. 2024;40(5):e279-e290.].
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Dou S, Liu X, Shi W, Gao H. New dawn for keratoconus treatment: potential strategies for corneal stromal regeneration. Stem Cell Res Ther 2023; 14:317. [PMID: 37932824 PMCID: PMC10629149 DOI: 10.1186/s13287-023-03548-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/27/2023] [Indexed: 11/08/2023] Open
Abstract
Keratoconus is a progressive, ectatic and blinding disorder of the cornea, characterized by thinning of corneal stroma. As a highly prevalent among adolescents, keratoconus has been a leading indication for corneal transplantation worldwide. However, the severe shortage of donor corneas is a global issue, and the traditional corneal transplantation surgeries may superinduce multiple complications, necessitating efforts to develop more effective strategies for keratoconus treatment. In this review, we summarized several strategies to promote corneal stromal regeneration or improve corneal stromal thickness, including cell-based therapies, biosynthetic alternatives for inducing corneal regeneration, minimally invasive intrastromal implantation and bioengineered tissues for implantation. These strategies provided more accessible but safer alternatives from various perspectives for keratoconus treatment, paving the way for arresting the keratoconus progression in its earlier stage. For the treatments of corneal ectatic diseases beyond keratoconus, these approaches will provide important references and widen the therapy options in a donor tissue-independent manner.
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Affiliation(s)
- Shengqian Dou
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
| | - Xiaoxue Liu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Eye Hospital of Shandong First Medical University, Jinan, China
- School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Weiyun Shi
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Eye Hospital of Shandong First Medical University, Jinan, China
- School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Hua Gao
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China.
- Eye Hospital of Shandong First Medical University, Jinan, China.
- School of Ophthalmology, Shandong First Medical University, Jinan, China.
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Li N, Liu M, Tian G, Chen T, Lin Y, Qi X, Shi W, Gao H. Effects of femtosecond laser-assisted minimally invasive lamellar keratoplasty (FL-MILK) on mild-to-moderate and advanced keratoconus. Graefes Arch Clin Exp Ophthalmol 2023; 261:2873-2882. [PMID: 37171602 DOI: 10.1007/s00417-023-06093-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 04/13/2023] [Accepted: 04/26/2023] [Indexed: 05/13/2023] Open
Abstract
PURPOSE To compare the outcomes of femtosecond laser-assisted minimally invasive lamellar keratoplasty (FL-MILK) for mild-to-moderate keratoconus (KC) and advanced KC. METHODS Prospective case series study. Sixty-three eyes of 56 patients with progressive KC underwent FL-MILK were divided into group 1 [mean keratometry (Kmean) ≤ 53D] and group 2 (Kmean > 53D). Best spectacle-corrected visual acuity (BSCVA), Kmean, maximum keratometry (Kmax), anterior central corneal elevation (ACE), stiffness parameter A1 (SP-A1) and deformation amplitude (DA) were evaluated preoperatively and up to 24 months postoperatively. RESULTS Mean BSCVA improved from 0.34 ± 0.13 logMAR preoperatively to 0.25 ± 0.13 logMAR at 24 months postoperatively in group 1 (F = 10.10, P < .0001), and from 0.54 ± 0.31 logMAR to 0.40 ± 0.26 logMAR (F = 9.06, P = .0002) in group 2. Group 2 showed an average Kmax reduction of 10.9 D and an average Kmean reduction of 3.9 D at 24 months postoperatively (both P < .0001), whereas no significant change was observed in group 1. Average ACE decreased from 19.2 ± 10.0 to 5.2 ± 8.4 at 24 months postoperatively in group 1 (F = 28.5, P < .0001), and from 46.2 ± 16.3 to 19.1 ± 9.0 (F = 49.6, P < .0001) in group 2; SP-A1 increased from 53.8 ± 12.7 mmHg/mm to 95.9 ± 20.2 mmHg/mm in group 1 (F = 70.0, P < .0001), and from 38.6 ± 13.4 mmHg/mm to 89.3 ± 18.2 mmHg/mm (F = 96.9, P < .0001) in group 2; DA decreased from 1.30 ± 0.14 mm to 1.17 ± 0.13 mm in group 1 (F = 14.0, P < .0001), and from 1.40 ± 0.16 mm to 1.18 ± 0.10 mm (F = 27.6, P < .0001) in group 2. CONCLUSIONS FL-MILK can stabilize progressive KC in mild-to-moderate cases and advanced cases at 24-month follow-up. Steeper corneas are more likely to undergo flattening after FL-MILK. CLINICAL TRIAL Date of registration: July 16, 2017. The title of the trail: www. CLINICALTRIALS gov Trial registration number: NCT03229239. The name of the trial registry: ClinicalTrials.gov.
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Affiliation(s)
- Na Li
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Mingna Liu
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Ge Tian
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Tong Chen
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Yue Lin
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Xiaolin Qi
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Weiyun Shi
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Hua Gao
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China.
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China.
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China.
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Cano-Gómez LE, Casillas-Casillas E, Andrade-Lozano P, Ventura-Juárez J, Barba-Gallardo LF. Animal model of corneal ectasia in rabbits by intrastromal injection of type II collagenase. ARCHIVOS DE LA SOCIEDAD ESPANOLA DE OFTALMOLOGIA 2023; 98:206-212. [PMID: 36871853 DOI: 10.1016/j.oftale.2023.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 01/17/2023] [Indexed: 03/07/2023]
Abstract
INTRODUCTION Collagenase II has been used to induce experimental keratoconus in animal models. However, its effect when administered by intrastromal injection has not been studied, so the purpose of this study was to study the effects of intrastromal injection of collagenase II on corneal surface and corneal morphology. METHODS Six New Zealand rabbits were used, collagenase II was administered by intrastromal injection (5μL of 2.5mg/mL) in the right eyes and balanced salt solution in the left eyes. Keratometry was performed to evaluate curvature alteration, also at day 7 corneas were obtained and Hematoxylin-Eosin staining was performed to examine morphologic changes. Likewise, changes in type I collagen expression were investigated by Sirius Red staining and semiquantitative PCR. RESULTS K1, K2 and Km presented differences in the means with statistically significant changes. The morphological changes that were demonstrated were degradation and irregular arrangement of the corneal stroma, increase in the cellular density of keratocytes and slight cellular infiltration. Finally, it was demonstrated that there is greater expression of type I collagen fibers in the experimental group as opposed to the controls and the thickness of the fibers also increased due to the action of collagenase II, however, in terms of genetics there were no changes in the expression of type I collagen at molecular level between the control and experimental groups. CONCLUSIONS Collagenase II administered by intrastromal injection is able to induce changes in the corneal surface and stroma, being able to simulate a model of keratoconus.
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Affiliation(s)
- L E Cano-Gómez
- Maestría en Investigación Biomédica, Centro de Ciencias de la Salud, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - E Casillas-Casillas
- Departamento de Optometría, Centro de Ciencias de la Salud, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - P Andrade-Lozano
- Maestría en Investigación Biomédica, Centro de Ciencias de la Salud, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - J Ventura-Juárez
- Departamento de Morfología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - L F Barba-Gallardo
- Departamento de Optometría, Centro de Ciencias de la Salud, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico.
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McMonnies CW. Mechanisms of corneal trauma in response to rubbing and other intraocular pressure elevating activities in keratoconus. EXPERT REVIEW OF OPHTHALMOLOGY 2022. [DOI: 10.1080/17469899.2022.2153119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Charles W McMonnies
- Faculty of Medicine and Health, School of Optometry and Vision Science, University of New South Wales
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Recent Advancements in Molecular Therapeutics for Corneal Scar Treatment. Cells 2022; 11:cells11203310. [PMID: 36291182 PMCID: PMC9600986 DOI: 10.3390/cells11203310] [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: 07/14/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 11/17/2022] Open
Abstract
The process of corneal wound healing is complex and induces scar formation. Corneal scarring is a leading cause of blindness worldwide. The fibrotic healing of a major ocular wound disrupts the highly organized fibrillar collagen arrangement of the corneal stroma, rendering it opaque. The process of regaining this organized extracellular matrix (ECM) arrangement of the stromal layer to restore corneal transparency is complicated. The surface retention capacity of ocular drugs is poor, and there is a large gap between suitable corneal donors and clinical requirements. Therefore, a more efficient way of treating corneal scarring is needed. The eight major classes of interventions targeted as therapeutic tools for healing scarred corneas include those based on exosomes, targeted gene therapy, microRNAs, recombinant viral vectors, histone deacetylase inhibitors, bioactive molecules, growth factors, and nanotechnology. This review highlights the recent advancements in molecular therapeutics to restore a cornea without scarring. It also provides a scope to overcome the limitations of present studies and perform robust clinical research using these strategies.
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Single-cell atlas of keratoconus corneas revealed aberrant transcriptional signatures and implicated mechanical stretch as a trigger for keratoconus pathogenesis. Cell Discov 2022; 8:66. [PMID: 35821117 PMCID: PMC9276680 DOI: 10.1038/s41421-022-00397-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 03/15/2022] [Indexed: 12/22/2022] Open
Abstract
Keratoconus is a common ectatic corneal disorder in adolescents and young adults that can lead to progressive visual impairment or even legal blindness. Despite the high prevalence, its etiology is not fully understood. In this study, we performed single-cell RNA sequencing (scRNA-Seq) analysis on 39,214 cells from central corneas of patients with keratoconus and healthy individuals, to define the involvement of each cell type during disease progression. We confirmed the central role of corneal stromal cells in this disease, where dysregulation of collagen and extracellular matrix (ECM) occurred. Differential gene expression and histological analyses revealed two potential novel markers for keratoconus stromal cells, namely CTSD and CTSK. Intriguingly, we detected elevated levels of YAP1 and TEAD1, the master regulators of biomechanical homeostasis, in keratoconus stromal cells. Cyclical mechanical experiments implicated the mechanical stretch in prompting protease production in corneal stromal cells during keratoconus progression. In the epithelial cells of keratoconus corneas, we observed reduced basal cells and abnormally differentiated superficial cells, unraveling the corneal epithelial lesions that were usually neglected in clinical diagnosis. In addition, several elevated cytokines in immune cells of keratoconus samples supported the involvement of inflammatory response in the progression of keratoconus. Finally, we revealed the dysregulated cell-cell communications in keratoconus, and found that only few ligand-receptor interactions were gained but a large fraction of interactional pairs was erased in keratoconus, especially for those related to protease inhibition and anti-inflammatory process. Taken together, this study facilitates the understanding of molecular mechanisms underlying keratoconus pathogenesis, providing insights into keratoconus diagnosis and potential interventions.
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Gao H, Liu M, Li N, Chen T, Qi X, Xie L, Shi W. Femtosecond laser-assisted minimally invasive lamellar keratoplasty for the treatment of advanced keratoconus. Clin Exp Ophthalmol 2022; 50:294-302. [PMID: 35061331 DOI: 10.1111/ceo.14047] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/05/2021] [Accepted: 12/27/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND To evaluate the initial safety and efficacy of femtosecond laser-assisted minimal invasive lamellar keratoplasty (FL-MILK) for advanced keratoconus. METHODS Twenty-two patients (22 eyes) with advanced keratoconus were included in this prospective study. All the involved eyes underwent FL-MILK. The femtosecond laser was used to create an intrastromal pocket with a 2.3 mm incision in the recipient cornea. Then a stromal button with a diameter of 9.0 mm and a depth of 200 μm was gently inserted into the intrastromal pocket through the 2.3 mm incision and flattened. No sutures were applied. Follow-up was conducted for 24 months. RESULTS Twenty-two patients completed follow-up data for 12 months, 16 patients had 24 months follow-up. No epithelial implantation, infection or allogeneic rejection were observed during the follow-up. Based on baseline values, postoperative 12 months values and postoperative 24 months values, clinical significantly improvement was recorded in corrected distance visual acuity (CDVA) (0.40 ± 0.18 logMAR vs. 0.30 ± 0.12 logMAR and 0.23 ± 0.13 logMAR), the anterior central corneal elevation (29.14 ± 15.33 μm vs. 14.45 ± 13.75μm and 11.38 ± 8.33 μm), and corneal higher-order aberrations (3.536 ± 1.503 vs. 2.761 ± 1.517 and 0.994 ± 0.391). Corneal biomechanical properties in all eyes improved significantly. SP-A1 increased from 48.64 ± 12.87 preoperatively to 87.26 ± 21.01 postoperative 12 months and 88.77 ± 18.26 postoperative 24 months; deformation amplitude (DA) decreased from 1.36 ± 0.15 preoperatively to 1.21 ± 0.12 postoperative 12 months and 1.19 ± 0.19 postoperative 24 months. CONCLUSIONS Initial experience suggests that this minimally invasive transplantation may be a feasible option for advanced keratoconus. A larger cohort and longer follow-up are required to validate our results and establish long-term safety and efficacy of the procedure.
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Affiliation(s)
- Hua Gao
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China.,School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Mingna Liu
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China.,School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Na Li
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Tong Chen
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Xiaolin Qi
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China.,School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Lixin Xie
- School of Ophthalmology, Shandong First Medical University, Jinan, China.,Qingdao Eye Hospital of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, China
| | - Weiyun Shi
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China.,School of Ophthalmology, Shandong First Medical University, Jinan, China
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Yung M, Chen AC, Chung DD, Barrington A, Zhang J, Frausto RF, Magalhaes OA, Aldave AJ. Corneal ectasia associated with posterior lamellar opacification. Ophthalmic Genet 2021; 42:486-492. [PMID: 34003075 DOI: 10.1080/13816810.2021.1923034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Concomitant corneal ectasia and posterior lamellar corneal opacification is rare, and the genetic relationship between these two conditions is unclear. We report the genetic and clinical characterization of this phenotype in three unrelated individuals. MATERIALS AND METHODS One previously reported affected individual and two unreported, unrelated, affected individuals were recruited for the study. Subjects and unaffected relatives underwent slit lamp examination, refraction, and multi-modal imaging. Saliva samples were obtained from two of the three affected individuals, from which DNA was extracted. Sanger sequencing was performed to identify mutations in genes associated with posterior amorphous corneal dystrophy (PACD), brittle cornea syndrome (BCS), and posterior polymorphous corneal dystrophy (PPCD), while copy number variation (CNV) analysis was used to identify CNV in the PACD locus. RESULTS Affected individuals demonstrated bilateral corneal steepening, stromal thinning and lamellar posterior corneal opacification. Corneal topography and tomography revealed conical or globular corneal steepening and decreased thickness. Anterior segment optical coherence tomography demonstrated hyperreflectivity of the posterior stroma in each of the affected individuals. Genetic testing did not detect a heterozygous deletion involving the PACD locus on chromosome 12 or a pathogenic mutation in the genes associated with BCS or PPCD. CONCLUSIONS Corneal ectasia may be associated with posterior lamellar stromal opacification that appears consistent with PACD. However, genetic testing for PACD as well as BCS and PPCD in affected individuals fails to reveal pathogenic deletions or mutations, indicating that other genetic factors are involved.
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Affiliation(s)
- Madeline Yung
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, Calfornia, USA
| | - Angela C Chen
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, Calfornia, USA
| | - Doug D Chung
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, Calfornia, USA
| | - Alice Barrington
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, Calfornia, USA
| | - Junwei Zhang
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, Calfornia, USA
| | - Ricardo F Frausto
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, Calfornia, USA
| | | | - Anthony J Aldave
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, Calfornia, USA
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Flockerzi E, Daas L, Seitz B. Structural changes in the corneal subbasal nerve plexus in keratoconus. Acta Ophthalmol 2020; 98:e928-e932. [PMID: 32275356 DOI: 10.1111/aos.14432] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 03/01/2020] [Accepted: 03/16/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND Corneal confocal microscopy (CCM) allows visualizing slightest alterations within the corneal subbasal nerve plexus (SNP). Recent CCM studies based on the analysis of three-five CCM images per eye assumed a reduced corneal nerve fibre length (CNFL) in keratoconus (KC). METHODS The SNP of KC patients (n = 23, 13 contact lens wearing, 10 noncontact lens wearing) and patients without KC (n = 16) was examined by 10 CCM images of one eye per patient. The CNFL per frame area was calculated, and the SNP tortuosity was quantified by measuring (a) the amplitude of the curves and (b) the area under the curve (AUC) formed by the SNP. RESULTS Analysing 390 non-overlapping confocal images revealed the CNFL (mm/mm2 ) to be significantly lower in KC (16.4 ± 1.9 mm/mm2 ) than in healthy corneae (23.8 ± 3.3 mm/mm2 , p < 0.0001; mean ± SD; p-value calculated using the Mann-Whitney U-test), without a difference between contact lens wearing and noncontact lens wearing KC patients (p = 0.4). Amplitudes and AUCs analysed as median with 25th and 75th percentile were significantly increased in KC (amplitude 33/23/41 µm and AUC 2839/1545/3444 µm2 ) compared to healthy corneae (amplitude 24/18/28 µm and AUC 1870/1193/2327 µm2 , p < 0.0001). CONCLUSIONS Corneal confocal microscopy (CCM) visualizes slightest alterations within the SNP in KC including (a) a significantly lower CNFL and (b) an enhanced winding course of the SNP. The significantly lower CNFL observed in KC may support the hypothesis of a neurodegenerative aspect of the disease and might be a measure to be correlated with the severity and progression of the disease.
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Affiliation(s)
- Elias Flockerzi
- Department of Ophthalmology Saarland University Medical Center Homburg Germany
| | - Loay Daas
- Department of Ophthalmology Saarland University Medical Center Homburg Germany
| | - Berthold Seitz
- Department of Ophthalmology Saarland University Medical Center Homburg Germany
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11
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Li M, Wei R, Yang W, Shang J, Fu D, Xia F, Choi J, Zhou X. Femtosecond Laser-Assisted Allogenic Lenticule Implantation for Corneal Ectasia After LASIK: A 3-Year In Vivo Confocal Microscopic Investigation. J Refract Surg 2020; 36:714-722. [PMID: 33170278 DOI: 10.3928/1081597x-20200826-02] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/13/2020] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate morphological changes in the cornea and the implanted lenticule in patients with corneal ectasia after laser in situ keratomileusis (LASIK) and implantation using a lenticule from small incision lenticule extraction (SMILE). METHODS Eight eyes of 8 patients with ectasia after LASIK from 2015 to 2018 at the Eye and ENT Hospital of Fudan Unversity were analyzed. For recipient eyes, lenticules were transferred with a mean cryopreserved time of 20 ± 21 days extracted from SMILE donors to the exposed stromal bed after lifting the flaps and the flap was repositioned. Uncorrected and corrected distance visual acuity, manifest refraction, and corneal topography were performed. Patients were followed up for 3 years. Changes in lenticules and recipient corneas were analyzed using in vivo confocal microscopy. RESULTS Activated keratocytes in the anterior and posterior stroma were observed near the lenticule at the first 6 months. Elongated, deformed keratocyte nuclei were found in the implanted lenticules in postoperative year 1. The anterior and posterior interfaces showed an absence or decrease of keratocytes and the presence of small particles of varying brightness. Nerve fibers in the implanted lenticules were detected in one case. No obvious difference was detected between cryopreserved and fresh lenticules. CONCLUSIONS The preliminary findings suggest that recipient keratocytes repopulate the lenticules and the keratocytes in lenticules gradually return to their normal morphology. [J Refract Surg. 2020;36(11):714-722.].
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Shetty R, Vunnava KP, Dhamodaran K, Matalia H, Murali S, Jayadev C, Murugeswari P, Ghosh A, Das D. Characterization of Corneal Epithelial Cells in Keratoconus. Transl Vis Sci Technol 2018; 8:2. [PMID: 30627477 PMCID: PMC6322712 DOI: 10.1167/tvst.8.1.2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 11/09/2018] [Indexed: 01/08/2023] Open
Abstract
Purpose We studied the cellular characteristics of epithelial cells in the cone and extraconal periphery of corneas in keratoconus eyes. Methods This prospective observational study was conducted at Narayana Nethralaya Eye Institute. A total of 83 and 42 eyes with keratoconus and normal topography, respectively, were included in the study. Corneal epithelial cells were collected and analyzed for apoptosis, proliferation, epithelial-mesenchymal transition, and differentiation status using molecular and biochemical tools. Statistical analysis was performed using the Student's t-test. Results Corneal epithelial cells from the cone showed significantly higher expression of proapoptotic marker BAX (P < 0.005) compared to controls. Significantly elevated expression of cell cycle markers CYCLIN D1 (P < 0.005) and Ki67 (P < 0.005) were noted in the extraconal region compared to controls. Cells of the cone showed significantly higher ZO-1 (P < 0.005) and lower vimentin (P < 0.005) compared to controls. Significantly lower expression of the differentiation marker CK3/12 (P < 0.05) was observed in cones compared to controls. Conclusions Cones of keratoconic corneas show enhanced cell death, poor differentiation, proliferation and epithelial-mesenchymal transition. The cellular changes of the corneal epithelial cells in the cone and extraconal region differ significantly in a keratoconus corneas. Translational Relevance Characterization of patient-specific corneal epithelial cellular status in keratoconus has the potential to determine the optimal treatment and therapeutic outcomes paving the way towards personalized treatment in the future.
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Affiliation(s)
- Rohit Shetty
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Institute, Bangalore, Karnataka, India
| | - Krishna Poojita Vunnava
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Institute, Bangalore, Karnataka, India
| | - Kamesh Dhamodaran
- Stem Cell Research Laboratory, GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India.,Current address: Department of Basic Sciences, The Ocular Surface Institute, College of Optometry, University of Houston, Houston, TX, USA
| | - Himanshu Matalia
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Institute, Bangalore, Karnataka, India
| | - Subramani Murali
- Stem Cell Research Laboratory, GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India
| | - Chaitra Jayadev
- Department of Vitreo-Retinal Services, Narayana Nethralaya Eye Institute, Bangalore, Karnataka, India
| | - Ponnulagu Murugeswari
- Stem Cell Research Laboratory, GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India
| | - Arkasubhra Ghosh
- GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India
| | - Debashish Das
- Stem Cell Research Laboratory, GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India
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In vivo confocal microscopy of toxic keratopathy. Eye (Lond) 2016; 31:140-147. [PMID: 27740620 PMCID: PMC5233937 DOI: 10.1038/eye.2016.213] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Accepted: 08/31/2016] [Indexed: 11/27/2022] Open
Abstract
Purpose To explore the morphological characteristics of toxic keratopathy (TK), which clinically presented as superficial punctate keratopathy (SPK), with the application of in vivo laser-scanning confocal microscopy (LSCM), and evaluate its potential in the early diagnosis of TK. Patients and methods This was a cross-sectional study involving 16 patients with TK and 16 patients with dry eye (DE), demonstrating SPK under slit-lamp observation, and 10 normal eyes were enrolled in the study. All participants underwent history interviews, fluorescein staining, tear film break-up time (BUT) tests, Schirmer tests, and in vivo LSCM. Results The area grading of corneal fluorescein punctate staining was higher in the TK group than the DE group. Measured by in vivo LSCM, superficial epithelial cell density was lower in the TK group than that of DE group. The sub-basal nerve presented lower density and tortuosity in the TK group than the DE group. Most notably, deposits with a snow-like appearance were observed in the epithelium in 12/16 (75.0%) of the TK cases, but none in the DE group (P<0.05). Conclusion The SPK in TK patients was characterized by more widespread punctate staining, a lower density of superficial epithelial cells and sub-basal nerves, and a typical snow-like pattern of deposits in the epithelium by LSCM. These features might facilitate early diagnosis of TK from other disorders manifested as SPK.
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