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Kapelushnik N, Werner L, Levinger N, Levinger S, Barequet IS. Ex Vivo Histological Analysis of Corneas with Manually Implanted Intracorneal Stromal Ring Segments. J Clin Med 2024; 13:3350. [PMID: 38893062 PMCID: PMC11172415 DOI: 10.3390/jcm13113350] [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: 01/30/2024] [Revised: 05/29/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024] Open
Abstract
Backgrond: Intracorneal ring segments (ICRSs) are utilized to correct refractive changes impacting visual acuity, commonly implanted via femtosecond laser but can also inserted manually. Corneal deposits alongside the ICRS channels are seen commonly. Methods: This study explores the histological characteristics of corneal deposits following manual ICRS implantation, comparing them to previously published articles describing femtosecond laser-assisted cases. Results: This is a retrospective analysis of three cases involving manual ICRS implantation, accumulation of whitish deposits and later explanation of the corneas due to penetrating keratoplasty (PKP). Patient demographics, ocular history, and surgical details were collected. Histological analysis employed Hematoxylin and Eosin (H&E) and Masson's trichrome staining. Whitish deposits along ICRS tracts were observed in all cases, with minimal fibroblastic transformation of keratocytes adjacent to the segments. Comparing these cases of manual to femtosecond laser-assisted ICRS implantation, in most cases, similar deposits were identified, indicating the deposits' association with the stromal tissue reaction to the ring segment and not to the surgical technique. Conclusions: This study contributes insights into the histopathology of manually implanted ICRS, emphasizing the shared nature of deposits in both insertion methods. The findings highlight the link between deposits and the stromal tissue reaction to the ring segment, irrespective of the insertion technique.
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Affiliation(s)
- Noa Kapelushnik
- Goldschleger Eye Institute, Sheba Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo 6997801, Israel;
| | - Liliana Werner
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT 84112, USA
| | - Nadav Levinger
- Enaim Refractive Surgery Center, Jerusalem 9438307, Israel (S.L.)
| | - Samuel Levinger
- Enaim Refractive Surgery Center, Jerusalem 9438307, Israel (S.L.)
| | - Irina S. Barequet
- Goldschleger Eye Institute, Sheba Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo 6997801, Israel;
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Albertazzi R, Rocha-de-Lossada C, Perrone LD, Valvecchia G, Perrone F, Ferlini L, Taboada D, Roude AL. Late-onset distal-apical intracorneal ring-segments keratopathy: an analysis of a large sample in a multicenter study. Int Ophthalmol 2023; 43:3923-3933. [PMID: 37531002 DOI: 10.1007/s10792-023-02793-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/22/2023] [Indexed: 08/03/2023]
Abstract
PURPOSE To review the prevalence and describe the characteristics, of cases with late-onset intracorneal ring segments (ICRS) keratopathy in a multicenter study. METHODS A retrospective multicentric case-series study was performed in a specialized keratoconus service, from Buenos Aires, Argentina. An electronic clinical chart from patients with ICRS keratopathy between January 1999 and January 2019 was reviewed. We included cases with late-onset distal-apical ICRS keratopathy, which was defined as a persistent corneal lesion developed 12 months or later after implantation, located over, around, or closer to the ICRS. All the surgeries were performed by a manual corneal tunnel creation technique. Samples were taken to rule out infectious etiology. RESULTS From 5217 eyes that underwent ICRS implantation, 13 cases (0.24%) were detected. The keratopathy onset was 72 ± 42.98 months (29-133) after ICRS implantation. Cultures were negative in all cases. An ICRS exchange was made for five cases in stage I and four in stage II. Four cases presented with partial ICRS extrusion in stage III. ICRS exchange was possible in two of them and a penetration keratoplasty was necessary for the rest. All cases remained stable 1 year after surgical procedures. CONCLUSIONS A late-onset distal-apical ICRS keratopathy was detected with low prevalence (0.24%) in a large sample. It was classified into three stages according to its severity. Different treatments were selected for each stage, obtaining stable results 1 year after treatment.
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Affiliation(s)
- Roberto Albertazzi
- Centro de Ojos Quilmes (Keratoconus Service), Humberto Primo, 298, 1878, Quilmes, Buenos Aires, Argentina.
| | - Carlos Rocha-de-Lossada
- Qvision-Vithas, Almeria; Vithas Málaga (Department of Ophthalmology; Spain), Almería, Spain
- Department of Ophthalmology, Regional University Hospital of Málaga; Department of Surgery, Ophthalmology, Universidad de Sevilla, Málaga, Spain
| | - Luciano D Perrone
- Centro de Ojos Quilmes (Keratoconus Service), Humberto Primo, 298, 1878, Quilmes, Buenos Aires, Argentina
| | - Gerardo Valvecchia
- Centro de Ojos Quilmes (Keratoconus Service), Humberto Primo, 298, 1878, Quilmes, Buenos Aires, Argentina
| | - Franco Perrone
- Centro de Ojos Quilmes (Keratoconus Service), Humberto Primo, 298, 1878, Quilmes, Buenos Aires, Argentina
| | - Leonardo Ferlini
- Centro de Ojos Quilmes (Keratoconus Service), Humberto Primo, 298, 1878, Quilmes, Buenos Aires, Argentina
| | - Delfina Taboada
- Centro de Ojos Quilmes (Keratoconus Service), Humberto Primo, 298, 1878, Quilmes, Buenos Aires, Argentina
| | - Alfredo L Roude
- Clínica de Ojos Nano (Cornea Service), Olivos, Buenos Aires, Argentina
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Hamon L, Schlötzer-Schrehardt U, Flockerzi FA, Seitz B, Daas L. Morphological characterization and clinical effects of stromal alterations after intracorneal ring segment implantation in keratoconus. Graefes Arch Clin Exp Ophthalmol 2022; 260:2299-2308. [PMID: 35106630 PMCID: PMC9203383 DOI: 10.1007/s00417-022-05572-2] [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: 10/21/2021] [Revised: 01/16/2022] [Accepted: 01/20/2022] [Indexed: 01/15/2023] Open
Abstract
PURPOSE To analyze the histological and (ultra)structural stromal tissue changes after femtosecond (Fs) laser-assisted intracorneal ring segment (ICRS) implantation and their refractive and topographic effects in patients with keratoconus. METHODS This monocentric retrospective case series included 15 consecutive patients with clinical peri-segmental lamellar channel deposits after treatment with Fs-ICRS implantation for keratoconus. The stromal changes were investigated using in vivo confocal microscopy. Two patients underwent a penetrating keratoplasty after the Fs-ICRS implantation; the explanted corneas were processed for histopathology and transmission electron microscopy (TEM). Refractive and topographic effects were investigated comparing the uncorrected (UDVA) and corrected (CDVA) distance visual acuity, spherical equivalent (SE), flat (K1), steep (K2), and steepest (Kmax) keratometry before and after detection of lamellar channel deposits. RESULTS In vivo confocal microscopy revealed diffuse linear and focal granular hyperreflective structures. Histologically, there was mild proliferation of fibroblasts and fibrosis. TEM demonstrated focal accumulations of degenerated keratocytes with cytoplasmic lipid inclusions. There were no significant changes for UDVA (Δ = 0.0 ± 0.2 logMAR; p = 0.67), CDVA (Δ = 0.0 ± 0.1 logMAR; p = 0.32), SE (Δ 0.1 ± 0.9 D; p = 0.22), K1 (Δ = 0.3 ± 1.0 D; p = 0.28), K2 (Δ = 0.1 ± 0.9 D; p = 0.51), and Kmax (Δ = 0.3 ± 1.5 D; p = 0.17). CONCLUSIONS Two types of structural stromal changes were identified: (1) diffuse peri-segmental fibrosis and (2) lamellar channel deposits. These structural changes showed no evidence of a relevant refractive or topographic effect.
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Affiliation(s)
- Loïc Hamon
- Department of Ophthalmology, Saarland University Medical Center (UKS), Kirrberger Straße 100, Bld. 22, 66421 Homburg, Saar Germany
| | - Ursula Schlötzer-Schrehardt
- Department of Ophthalmology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Fidelis A. Flockerzi
- Department of Pathology, Saarland University Medical Center (UKS), Homburg, Saar Germany
| | - Berthold Seitz
- Department of Ophthalmology, Saarland University Medical Center (UKS), Kirrberger Straße 100, Bld. 22, 66421 Homburg, Saar Germany
| | - Loay Daas
- Department of Ophthalmology, Saarland University Medical Center (UKS), Kirrberger Straße 100, Bld. 22, 66421 Homburg, Saar Germany
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Hamon L, Seitz B, Daas L. Intrastromal fibrosis and lipid deposits twenty years after intracorneal ring segments implantation for treatment of mild myopia. J Fr Ophtalmol 2021; 45:147-150. [PMID: 34802752 DOI: 10.1016/j.jfo.2021.06.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/25/2021] [Accepted: 06/04/2021] [Indexed: 10/19/2022]
Affiliation(s)
- L Hamon
- Centre Hospitalier Universitaire de la Sarre (UKS), Homburg/Saar, Germany.
| | - B Seitz
- Centre Hospitalier Universitaire de la Sarre (UKS), Homburg/Saar, Germany
| | - L Daas
- Centre Hospitalier Universitaire de la Sarre (UKS), Homburg/Saar, Germany
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D'Oria F, Abdelghany AA, Ledo N, Barraquer RI, Alio JL. Incidence and Reasons for Intrastromal Corneal Ring Segment Explantation. Am J Ophthalmol 2021; 222:351-358. [PMID: 33011155 DOI: 10.1016/j.ajo.2020.09.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/28/2022]
Abstract
PURPOSE To determine the main causes of intrastromal corneal ring segment (ICRS) explantation and define the incidence rate. DESIGN Multicenter, observational consecutive case series. METHODS Consecutive cases of ICRSs explanted in the last 10 years were reviewed. Clinical data included age of the patients at explantation, reasons for implantation and explantation, date of implantation and explantation, tunnel creation technique, and ICRS type. Main outcomes measures were the reasons for ICRS removal and the incidence rate. RESULTS During the study period, 121 ICRSs (119 patients) were explanted, with an explantation rate of 5.60%. Functional failure (74 eyes, 61.16%) represents the main cause for ICRS removal: of them, 48 (39.67%) ICRSs were removed for refractive failure and 26 (21.49%) in the setting of a keratoplasty related to poor visual performance of the implanted eye. In addition, 47 eyes (38.84%) had ICRS removal for anatomic failure: among them, 36 (29.75%) were explanted for spontaneous extrusion (overall extrusion rate: 1.58%), 7 (5.79%) for suspected infectious keratitis, 3 (2.48%) for corneal melting, and 1 (0.83%) for corneal perforation. Mild cases of keratoconus were more prone to be explanted because of a loss of the initial improved visual acuity, whereas spontaneous extrusion happened often in advanced cases of keratoconus. CONCLUSIONS We report the largest series of ICRS explantation as of this writing. The main cause of explantation was functional refractive failure followed by spontaneous extrusion of the ICRS, that is, correlated to an anatomic failure at the site of implantation in an advanced disease.
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Affiliation(s)
- Francesco D'Oria
- Vissum Innovation, Alicante, Spain; Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain; Section of Ophthalmology, Department of Basic Medical Science, Neuroscience and Sense Organs, University of Bari, Bari, Italy
| | - Ahmed A Abdelghany
- Vissum Innovation, Alicante, Spain; Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain; Ophthalmology department, Faculty of Medicine, Minia University, Minia, Egypt
| | - Natalia Ledo
- Instituto Universitario Barraquer, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Rafael I Barraquer
- Instituto Universitario Barraquer, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Jorge L Alio
- Vissum Innovation, Alicante, Spain; Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain.
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Eliaçık M, Kırgız A, Tülü Aygün B. Evaluation of corneal thickness with spectral-domain optical coherence tomography following keraring implantation for keratoconus: five year follow-up. Curr Eye Res 2020; 45:1359-1363. [PMID: 32228114 DOI: 10.1080/02713683.2020.1749667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
To evaluate the change in the position of intrastromal corneal ring segments (ICRS) implanted in keratoconus patients within five years of implantation. Participants in this study included keratoconus patients who received Keraring 10 ICRS implantation and had a follow-up time of at least 5 years. The distances from apex to anterior corneal surface (AA), from outer basal corner to posterior corneal surface (BP), and from inner basal corner to posterior corneal surface (CP) were measured at every postoperative visit (6 months, 1 year, 3 years, and 5 years) and compared to each other. Thirty eyes of 22 patients were included. The CP showed a statistically significant decrease at all 15 time points (p < .001); however, no statistically significant difference was found at 5 years regarding AA or BP (p > .05 for all). Triangular ICRS implanted in keratoconus patients remained stable for five years without any complications, which is an extremely important aspect of ICRS surgery. The only difference was a slight posterior movement of the inner basal corner, although without anterior chamber perforation.
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Affiliation(s)
- Mustafa Eliaçık
- School of Medicine, Department of Ophthalmology, Medipol University , Istanbul, Turkey
| | - Ahmet Kırgız
- Ophthalmology Department, Beyoglu Eye Training and Research Hospital, University of Health Sciences , Istanbul, Turkey
| | - Beril Tülü Aygün
- Ophthalmology Department, Beyoglu Eye Training and Research Hospital, University of Health Sciences , Istanbul, Turkey
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Ibares-Frías L, Gallego-Muñoz P, Orive G, Anitua E, Cantalapiedra-Rodríguez R, Merayo-Lloves J, Martínez-García M. Potential Effect of Plasma Rich in Growth Factors-Endoret in Stromal Wound Healing in Additive Surgery. Ophthalmic Res 2019; 63:203-212. [DOI: 10.1159/000501507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 06/17/2019] [Indexed: 11/19/2022]
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Bautista-Llamas MJ, Sánchez-González MC, López-Izquierdo I, López-Muñoz A, Gargallo-Martínez B, De-Hita-Cantalejo C, Sánchez-González JM. Complications and Explantation Reasons in Intracorneal Ring Segments (ICRS) Implantation: A Systematic Review. J Refract Surg 2019; 35:740-747. [DOI: 10.3928/1081597x-20191010-02] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/10/2019] [Indexed: 11/20/2022]
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Merayo-Lloves J, Blanco-Mezquita T, Ibares-Frías L, Fabiani L, Alvarez-Barcia A, Martinez-García C. Induction of Controlled Wound Healing with PMMA Segments in the Deep Stroma in Corneas of Hens. Eur J Ophthalmol 2018; 20:62-70. [DOI: 10.1177/112067211002000108] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Purpose Polymethylmethacrylate (PMMA) segments are normally used in additive surgery to treat both corneal ectasia post laser-assisted in situ keratomileusis and keratoconus. The aim of this work was to develop an experimental animal model to induce wound healing in the deep stroma in corneas of hens. Methods PMMA segments were implanted in the right eyes of 40 adult hens without suture in the wound incision. Animals were randomized for 5 time points to histopathology study (1, 3, 15, 30, and 90 days) being clinically evaluated during the experiment. Results Thirty-four eyes (85%) had a successful clinical outcome and intraoperative mistakes occurred in 6 eyes (15%), including anterior chamber perforation resulting in abscess (1), excess of lamellar dissection with segment migration (3), and peripheral incisions evolving with neovascularization (2). At 24 hours, all the epithelial injuries were completed in integrity, but a persistent stromal incision, with a fish mouth form, was observed until day 15. Corneal edema disappeared at the fifth day. Haze, keratocyte cell death, keratocyte proliferation, myofibroblast differentiation, and new matrix production were observed in length around the segment. Conclusions Wound healing was induced in the deep corneal stroma by means of PMMA segment implantation in a new animal model developed in hens.
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Puell MC, Carballo-Álvarez J. Forward light scatter and visual acuity before and after intrastromal corneal ring segment implantation at different stages of keratoconus. Acta Ophthalmol 2016; 94:e738-e743. [PMID: 27129433 DOI: 10.1111/aos.13056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/15/2016] [Indexed: 12/01/2022]
Abstract
PURPOSE To assess forward light scatter (stray light) before and after intrastromal corneal ring segment (ICRS) implantation at different stages of keratoconus and to examine correlation between postoperative stray light and visual acuity (VA). METHODS In 27 eyes of 27 subjects with keratoconus, stray light was determined using the compensation comparison technique before and 6 months after ICRS implantation. Monocular corrected distance VA (CDVA) was measured using a high-contrast logMAR letter chart. Corneal higher-order aberrations (HOAs), contrast sensitivity (CS) and minimum corneal thickness (CT) were also measured. RESULTS Mean CDVA was 0.42 ± 0.28 preoperatively and 0.24 ± 0.15 logMAR postoperatively (p < 0.01). Mean corneal coma-like aberration decreased postoperatively (RMS 0.55 ± 1.18 μm, p < 0.01). Minimum CT increased 25.31 ± 18.59 μm (p < 0.01). Mean preoperative and postoperative stray light were 1.36 ± 0.31 and 1.48 ± 0.32 log units, respectively (p < 0.01). Mean changes produced in stray light (worsening) were 0.03 ± 0.21 (p > 0.05) for stage I, 0.13 ± 0.14 (p = 0.013) for stage II and 0.18 ± 0.21 (p = 0.023) for stage III. Significant positive correlation (r = 0.47, p = 0.01) was detected between postoperative stray light and postoperative CDVA such that as stray light increased, CDVA worsened (higher logMAR values). Postoperative stray light was neither associated with HOAs, CS nor minimum CT. CONCLUSIONS Stray light values in these patients with keratoconus were higher than normal preoperatively. In eyes with stage II and III keratoconus, stray light increased 6 months after ICRS placement. Higher postoperative stray light was correlated with a worse visual acuity outcome.
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Affiliation(s)
- María Cinta Puell
- Applied Vision Research Group; Faculty of Optics and Optometry; Complutense University of Madrid; Madrid Spain
| | - Jesús Carballo-Álvarez
- Applied Vision Research Group; Faculty of Optics and Optometry; Complutense University of Madrid; Madrid Spain
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Ibares-Frías L, Gallego P, Cantalapiedra-Rodriguez R, Merayo-Lloves J, Martínez-García MC. Clinical, Refractive and Histological Reversibility of Corneal Additive Surgery in Deep Stroma in an Animal Model. Curr Eye Res 2016; 41:1192-201. [PMID: 26889567 DOI: 10.3109/02713683.2015.1114652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The aim was to evaluate the reversibility of the clinical and histological changes induced in the corneas of an animal model after removing an intracorneal ring segment (ICRS). METHODS Surgery for this study was performed in 38 eyes of an experimental animal model (Gallus domesticus) for ICRS surgery (Ferrara technique). The animals without complications were randomized to two groups; in all of them, 1 segment was implanted in each eye and later removed at different times (1 and 3 months after implantation). In each group, after explantation, corneas were processed at different times for histological analysis with hematoxylin and eosin (H&E) stain and electronic microscopy. The refractive state of the eyes was also measured. RESULTS In corneas without complications (88.23%), explantation was performed correctly. During the first few days, around the area where the ICRS was implanted we observed deposits of cells and a moderate degree of corneal opacity (haze). These signs decreased progressively without disappearing completely. Histologically, at 7 days, we observed hyperplasia and abnormal arrangement of collagen fibers. Later, these findings also decreased in both groups, albeit at a faster rate in group 1. Minimal changes were observed in electron microscopy up to the end of the study in both groups. Preoperative refractive state was achieved at 1 month after explantation in both groups. CONCLUSIONS ICRS can safely be explanted from the cornea. Refractive reversibility was achieved at 1 month after explantation. However, the clinical and histological findings after ICRS explantation depend on the time from implantation to explantation.
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Affiliation(s)
- Lucía Ibares-Frías
- a Optical Diagnostic Techniques Group, Theoretical, Atomic and Optical Physics Department , University of Valladolid , Valladolid , Spain.,b Ophthalmology Department , Hospital Clínico Universitario de Valladolid , Valladolid , Spain
| | - Patricia Gallego
- a Optical Diagnostic Techniques Group, Theoretical, Atomic and Optical Physics Department , University of Valladolid , Valladolid , Spain.,c Cell Biology, Histology and Pharmacology Department , Faculty of Medicine, University of Valladolid , Valladolid , Spain
| | | | - Jesús Merayo-Lloves
- a Optical Diagnostic Techniques Group, Theoretical, Atomic and Optical Physics Department , University of Valladolid , Valladolid , Spain.,d Instituto Universitario Fernandez-Vega, Universidad de Oviedo , Oviedo , Spain
| | - María Carmen Martínez-García
- a Optical Diagnostic Techniques Group, Theoretical, Atomic and Optical Physics Department , University of Valladolid , Valladolid , Spain.,c Cell Biology, Histology and Pharmacology Department , Faculty of Medicine, University of Valladolid , Valladolid , Spain
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Kramer EG, Boshnick EL. Scleral lenses in the treatment of post-LASIK ectasia and superficial neovascularization of intrastromal corneal ring segments. Cont Lens Anterior Eye 2015; 38:298-303. [DOI: 10.1016/j.clae.2015.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 02/02/2015] [Indexed: 10/23/2022]
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Histological and confocal changes in rabbit cornea produced by an intrastromal inlay made of hexafocon A. Cornea 2015; 34:78-81. [PMID: 25357077 DOI: 10.1097/ico.0000000000000289] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim of this study was to evaluate biocompatibility of a newly proposed intrastromal inlay in rabbit corneas. METHODS Eighteen eyes of 9 New Zealand rabbits were included in this prospective study. An intrastromal pocket was created in both eyes using Melles instruments. Annular intracorneal inlays made of hexafocon A were implanted randomly into the stromal pocket of one eye of each rabbit. Confocal microscopy was performed at each visit during 6-month follow-up. After 6 months, the rabbits were killed and corneal tissues of both eyes were sent for light microscopic studies. RESULTS Mild stromal edema was present during the first few days and disappeared afterward with mild haze around the tunnel site in all cases. Deposits around the lamellar channel developed in 3 implanted eyes and in none of the pocket-only eyes. No neovascularization or epithelial downgrowth was present at the incision site in any case. All inlays remained centered and optically clear. In confocal imaging, we observed no significant difference in keratocyte cell density and inflammatory cells between the control pocket-only group and inlay group. In pathological evaluation, there was no difference in the average epithelial thickness between both groups. Descemet membrane and endothelium appeared normal in both groups. CONCLUSIONS This study revealed safety and biocompatibility of hexafocon A as an intracorneal inlay in rabbits.
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Ibares-Frías L, Gallego P, Cantalapiedra-Rodríguez R, Valsero MC, Mar S, Merayo-Lloves J, Martínez-García MC. Tissue reaction after intrastromal corneal ring implantation in an experimental animal model. Graefes Arch Clin Exp Ophthalmol 2015; 253:1071-83. [PMID: 25744328 DOI: 10.1007/s00417-015-2959-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 01/22/2015] [Accepted: 01/27/2015] [Indexed: 01/04/2023] Open
Abstract
PURPOSE To evaluate corneal wound healing in the hen animal model after additive surgery with an intracorneal ring segment (ICRS). METHODS We implanted one ICRS in each eye of 76 hens. In control group 1 (n = 22 hens), the stromal channel was prepared but no ICRS was inserted. In control group 2 (n = 2 hens), no surgery was performed. Animals were randomly separated into groups and euthanized after clinical follow-up of 4 and 12 hours, 1, 2, 3, and 7 days, and 1, 2, 3, 4, and 6 months. Corneas were stained with hematoxylin-eosin. Apoptosis was measured by terminal uridine nick end-labeling assays. Cell proliferation and myofibroblast-like differentiation were assayed by BrdU and α-smooth muscle actin immunofluorescence microscopy. Stromal matrix changes were documented by electron microscopy. RESULTS Epithelial and stromal cell apoptosis around the ICRS-implanted and control group 1 eyes peaked at 12 hours, but continued for 72 hours. In ICRS-implanted eyes, epithelial and stromal proliferation was present at 12 and 24 hours, respectively, and peaked at 7 days and 72 hours, respectively. Some proliferation in the ICRS-implanted group continued through the 6-month follow-up, and myofibroblast-like cells differentiated one to three months after ICRS implantation. The segments rotated within the stroma as the limbal inferior angle approached the epithelium. CONCLUSIONS Wound healing after ICRS implantation in hen corneas was similar to that of other corneal surgical wounds in stages. However, there were some specific features related to the small size of the epithelial wound and the device permanently implanted inside the cornea.
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Affiliation(s)
- Lucía Ibares-Frías
- Group of Optical Diagnostic Techniques, Theorist, Atomic and Optical Physics Department, Faculty of Science, University of Valladolid, Valladolid, Spain,
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Andreghetti E, Hashimoto M, Domingues MAC, Antunes VAC, Segundo PDS, Silva MRBDM. Biocompatibility of Ferrara intracorneal ring segment with and without chondroitin sulfate coating. Clinical and histopathological evaluation in rabbits. Acta Cir Bras 2013; 28:632-40. [PMID: 24000055 DOI: 10.1590/s0102-86502013000900002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 08/16/2013] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To investigate and compare the biocompatibility of two types of Ferrara intracorneal ring segment: with and without chondroitin sulfate coating by clinical and histopathological evaluation. METHODS A randomized experimental study was carried out on thirty right-eye corneas from 30 Norfolk albino rabbits allocated into two experimental groups: Group G1 - implanted with Ferrara intracorneal ring segment without coating (FICRS) and Group G2 - implanted with Ferrara intracorneal ring segment with chondroitin sulfate coating (FICRS-CS). Left eyes formed the control group. Clinical parameters analyzed were: presence of edema, vascularization, infection and ring extrusion one, 30, and 60 days after surgery. Histopathological parameters analyzed were: number of corneal epithelial layers over and adjacent to the ring, presence of spongiosis, hydropic degeneration, basement membrane thinning, inflammatory cells, neovascularization and pseudocapsule formation. RESULTS At clinical examination 60 days after implant, edema, vascularization and extrusion were observed respectively in 20%, 26.7%, 6.7% of FICRS corneas and in 6.7%, 6.7%, and 0% of FICRS-CS corneas. Histopathological evaluation showed epithelial-layer reduction from 5 (5;6) to 3 (3;3) with FICRS and from 5 (5;5) to 4 (3;5) with FICRS-CS in the region over the ring. Epithelial spongiosis, hydropic degeneration, and basement membrane thinning were present in 69.2%, 53.8%, and 69.2% of FICRS and in 73.3%, 73.3%, and 46.7% with FICRS-CS, respectively. Vascularization was present in 38.5% of FICRS and 13.3% with FICRS-CS, inflammatory cells in 75% of FICRS and 33.3% with FICRS-CS, and pseudocapsule in 66.7% of FICRS and 93.3% with FICRS-CS. Giant cells occurred only in the FICRS-CS group (20%). CONCLUSION Ferrara intracorneal rings coated with chondroitin sulfate (FICRS-CS) caused lower frequency of clinical and histopathological alterations than Ferrara intracorneal rings without the coating (FICRS), demonstrating higher biocompatibility of the FICRS-CS.
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Affiliation(s)
- Eduardo Andreghetti
- Postgraduate Program in Surgery, Faculty of Medicine of Botucatu (FMB), Sao Paulo State University (UNESP), Botucatu-SP, Brazil
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Bedi R, Touboul D, Pinsard L, Colin J. Refractive and Topographic Stability of Intacs in Eyes With Progressive Keratoconus: Five-year Follow-up. J Refract Surg 2012; 28:392-6. [DOI: 10.3928/1081597x-20120509-01] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 04/24/2012] [Indexed: 11/20/2022]
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Al-Amry M, Alkatan HM. Histopathologic findings in two cases with history of intrastromal corneal ring segments insertion. Middle East Afr J Ophthalmol 2012; 18:317-9. [PMID: 22224023 PMCID: PMC3249820 DOI: 10.4103/0974-9233.90136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Intrastromal corneal ring segments (INTACS) implantation for mild myopia or keratoconus is simple and effective in most cases. Rarely, major complications can occur due to implantation. In this case report, we present two examples of possible intraoperative and postoperative complications of INTACS. The first case had histopathologic documentation of Descemet's membrane perforation as an intraoperative complication and the second case had accumulation of foamy histiocytes along the lamellar channels which has not been previously reported. These complications suggest further study is required on the long term effect of INTACS implantation on corneal tissue.
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Affiliation(s)
- Mohammad Al-Amry
- Anterior Segment Division and Emergency Room, King Khaled Eye Specialist Hospital, Riyadh, Kingdom of Saudi Arabia
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Refractive and Keratometric Outcomes of Intacs Continue to Improve Until 6 Months. Cornea 2011; 30:1068; author reply 1068-9. [DOI: 10.1097/ico.0b013e3181eeb45f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Corneal Melt of Incisions Overlying Corneal Ring Segments: Case Series and Literature Review. Cornea 2011; 30:968-71. [DOI: 10.1097/ico.0b013e3182031ca0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Cao X, Ursea R, Shen D, Ramkumar HL, Chan CC. Hypocellular scar formation or aberrant fibrosis induced by an intrastromal corneal ring: a case report. J Med Case Rep 2011; 5:398. [PMID: 21854565 PMCID: PMC3177919 DOI: 10.1186/1752-1947-5-398] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 08/19/2011] [Indexed: 11/14/2022] Open
Abstract
Introduction Intrastromal corneal rings or segments are approved for the treatment of myopia and astigmatism associated with keratoconus. We describe a clinicopathological case of intrastromal corneal rings. For the first time, the molecular pathological findings of intrastromal corneal rings in the cornea are illustrated. Case presentation A 47-year-old African-American man with a history of keratoconus and failure in using a Rigid Gas Permeable contact lens received an intrastromal corneal ring implant in his left eye. Due to complications, penetrating keratoplasty was performed. The intrastromal corneal ring channels were surrounded by a dense acellular (channel haze) and/or hypocellular (acidophilic densification) collagen scar and slightly edematous keratocytes. Mild macrophage infiltration was found near the inner aspect of the intrastromal corneal rings. Molecular analyses of the microdissected cells surrounding the intrastromal corneal ring channels and central corneal stroma revealed 10 times lower relative expression of IP-10/CXCL10 mRNA and two times higher CCL5 mRNA in the cells surrounding the intrastromal corneal ring, as compared to the central corneal stroma. IP-10/CXCL10 is a fibrotic and angiostatic chemokine produced by macrophages, endothelial cells and fibroblasts. Conclusion An intrastromal corneal ring implant can induce hypocellular scar formation and mild inflammation, which may result from aberrant release of fibrosis-related chemokines.
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Affiliation(s)
- Xiaoguang Cao
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA.
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A perfluoropolyether corneal inlay for the correction of refractive error. Biomaterials 2011; 32:3158-65. [PMID: 21306775 DOI: 10.1016/j.biomaterials.2011.01.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 01/12/2011] [Indexed: 11/24/2022]
Abstract
This study assessed the long-term biological response of a perfluoropolyether-based polymer developed as a corneal inlay to correct refractive error. The polymer formulation met chemical and physical specifications and was non-cytotoxic when tested using standard in vitro techniques. It was cast into small microporous membranes that were implanted as inlays into corneas of rabbits (n = 5) and unsighted humans (n = 5 + 1 surgical control) which were monitored for up to 23 and 48 months respectively. Overall, the inlays were well tolerated during study period with the corneas remaining clear and holding a normal tear film and with no increased vascularisation or redness recorded. Inlays in three human corneas continued past 48 months without sequelae. Inlays in two human corneas were removed early due to small, focal erosions developing 5 and 24 months post-implantation. Polymer inlays maintained their integrity and corneal position for the study duration although the optical clarity of the inlays reduced slowly with time. Inlays induced corneal curvature changes in human subjects that showed stability with time and the refractive effect was reversed when the inlay was removed. Outcomes showed the potential of a perfluoropolyether inlay as a biologically acceptable corneal implant with which to provide stable correction of refractive error.
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Pérez-Merino P, Parra F, Ibares-Frías L, Gallego P, Vázquez-Lasa B, Benito L, San Román J, Martínez-García C, Merayo-Lloves J. Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery. Acta Biomater 2010; 6:2572-9. [PMID: 20080217 DOI: 10.1016/j.actbio.2010.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 12/17/2009] [Accepted: 01/11/2010] [Indexed: 11/19/2022]
Abstract
The objective of this work was to evaluate the potential use of less stiff materials based on acrylic copolymers of methyl methacrylate/2-ethylhexyl acrylate (MMA/EHA) as devices to correct, stabilize and improve the effect of poly(methyl methacrylate) (PMMA) intracorneal ring segments. MMA/EHA and PMMA intracorneal ring segments were surgically implanted in the corneas of Lohmann Classic hens. The effects of the intracorneal ring segments were assessed by optical measurements and corneal tolerance was evaluated through biomicroscopic examination over a 90-day observation period and by conventional histology. The experimental results demonstrated that the intracorneal ring segments made of MMA/EHA copolymers provided a significant change in the corneal curvature and an improved in vivo response compared to those obtained for PMMA rings, which was attributed to the higher flexibility of the copolymeric materials, indicating that these systems might be considered suitable as an alternative to those currently used, for application in clinical practice.
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Affiliation(s)
- P Pérez-Merino
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), University of Valladolid, Valladolid, Spain
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Ferrer C, Alió JL, Montañés AU, Pérez-Santonja JJ, Diaz del Rio MA, de Toledo JA, Teus MA, Javaloy J. Causes of intrastromal corneal ring segment explantation: Clinicopathologic correlation analysis. J Cataract Refract Surg 2010; 36:970-7. [DOI: 10.1016/j.jcrs.2009.12.042] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 11/27/2009] [Accepted: 12/03/2009] [Indexed: 10/19/2022]
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[Spectral-domain optical coherence tomography in anterior segment imaging: the 3rd dimension]. J Fr Ophtalmol 2010; 32:727-34. [PMID: 19944481 DOI: 10.1016/j.jfo.2009.10.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 10/16/2009] [Indexed: 11/23/2022]
Abstract
PURPOSE Anterior segment imaging using optical coherence tomography (OCT) time domain technology has been used for many years. When it appeared, it was a promising technique in the analysis of the anterior segment, making it possible to reach a definition of the ocular structures comparable with histology. Now with new-generation OCT, it is possible to perform high-definition and three-dimensional imaging. MATERIAL AND METHOD A 3D OCT-1000 (Topcon, Tokyo, Japan) parameterized to obtain high-definition and 3D imaging of the iridocorneal structures. RESULTS We present a collection of images obtained using this technique. DISCUSSION Based on a very sophisticated tool for retinal and glaucoma imagery, it is now possible to obtain very-high-quality imaging of the anterior segment, which, with its great versatility, increases the value of acquiring this type of device. CONCLUSIONS The potential of 3D OCT-1000, already a very good exam for the posterior segment, and the only one to perform anterior segment three-dimensional imaging in a single acquisition, should not be neglected.
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Kymionis GD, Grentzelos MA, Diakonis VF, Pallikaris AI, Pallikaris IG. Nine-year follow-up of intacs implantation for keratoconus. Open Ophthalmol J 2009; 3:77-81. [PMID: 20087439 PMCID: PMC2808049 DOI: 10.2174/1874364100903010077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 07/06/2009] [Accepted: 08/13/2009] [Indexed: 11/22/2022] Open
Abstract
Purpose: To present a case of nine- year bilateral Intacs (Addition Technology, Inc, Fremont, California, USA) implantation for early stage keratoconus. Methods: A 25-year-old male underwent bilateral Intacs implantation for the management of keratoconus and hardcontact-lens intolerance (stage 1) in 1999. Results: Nine years postoperatively, spherical equivalent refraction changed from preoperative -0.75 and -2.25 to +0.75 and –1.25 for the right and the left eye, respectively. UCVA was improved from 20/50 to 20/25 in the right and from 20/200 to 20/32 in the left eye. BSCVA of 20/20 in the right eye maintained stable in comparison with the Pre-Intacs BSCVA, while BSCVA was improved from 20/25 to 20/20 in the fellow eye. No early or late complications were observed. Conclusions: Nine years after bilateral Intacs implantation for the management of early stage keratoconus, there was a significant improvement and postoperative stability in patient’s visual acuity. No long-term, sight-threatening complications were identified during follow-up.
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Affiliation(s)
- George D Kymionis
- Institute of Vision and Optics, Department of Ophthalmology, Medical School, University of Crete, Greece
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Kojima T, Primack JD, Azar DT. Intrastromal Corneal Ring Segments for Low and High Myopia. Ophthalmology 2009. [DOI: 10.1016/b978-0-323-04332-8.00023-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Alterations of extracellular matrix components and proteinases in human corneal buttons with INTACS for post-laser in situ keratomileusis keratectasia and keratoconus. Cornea 2008; 27:565-73. [PMID: 18520507 DOI: 10.1097/ico.0b013e318165b1cd] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE To perform an immunohistochemical evaluation of corneas with INTACS for post-laser in situ keratomileusis (LASIK) keratectasia and keratoconus, obtained after corneal transplantation. METHODS Corneas from 1 patient with INTACS for post-LASIK keratectasia and 2 patients with INTACS for keratoconus were obtained within 3 hours after penetrating keratoplasty, and cryostat sections were analyzed by immunostaining for 35 extracellular matrix (ECM) components and proteinases. RESULTS In the stroma of all corneas next to an INTACS implant, ECM components typically associated with fibrosis were observed. These included tenascin-C, fibrillin-1, and types III, IV (alpha1/alpha2 chains), and XIV collagen. Also, significant deposition of perlecan, nidogen-2, and cellular fibronectin was revealed in the same locations. The keratoconus cases displayed typical Bowman layer breaks and subepithelial fibrosis with deposition of various ECM components. In all cases, some keratocytes around INTACS were positive for specific proteinases associated with stromal remodeling, including cathepsins F and H, matrix metalloproteinase (MMP)-1, MMP-3, and MMP-10. Staining for MMP-7 was variable; MMP-2 and MMP-9 were mostly negative. Patterns of type IV collagen alpha 3, alpha 4, and alpha 6 chains; types VI and VIII collagen; laminin-332, alpha 4, alpha 5, beta1, beta2, and gamma 1 laminin chains; vitronectin; thrombospondin-1; urokinase; EMMPRIN; and cathepsins B and L were unchanged around INTACS in all 3 cases compared with normal. CONCLUSIONS Abnormal accumulation of fibrotic ECM components and proteinases near INTACS suggests ongoing lysis and remodeling of corneal stroma. Specific changes observed in each case may be related to underlying pathology.
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Ertan A, Colin J. Intracorneal rings for keratoconus and keratectasia. J Cataract Refract Surg 2007; 33:1303-14. [PMID: 17586391 DOI: 10.1016/j.jcrs.2007.02.048] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Accepted: 02/15/2007] [Indexed: 10/23/2022]
Abstract
Intrastromal corneal ring segments were designed to achieve refractive adjustment by flattening the cornea. Recently, they have been used to reshape keratoconic corneas to improve uncorrected visual acuity, best corrected visual acuity, and contact lens tolerance and to delay or prevent the need for keratoplasty. Intracorneal ring segments have several distinct and important advantages. New thicknesses and different ring sizes and the use of femtosecond lasers to dissect channels inside the cornea will likely improve the surgical outcomes. This article reviews the latest data published or presented at meetings on the correction of keratoconus and keratectasia by intracorneal ring segments.
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Affiliation(s)
- Aylin Ertan
- Kudret Eye Hospital, Ankara, Turkey, and the Bordeaux University, Bordeaux, France.
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Samimi S, Leger F, Touboul D, Colin J. Histopathological findings after intracorneal ring segment implantation in keratoconic human corneas. J Cataract Refract Surg 2007; 33:247-53. [PMID: 17276265 DOI: 10.1016/j.jcrs.2006.08.059] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Accepted: 08/25/2006] [Indexed: 11/23/2022]
Abstract
PURPOSE To evaluate histopathological changes induced in keratoconic corneas after implantation of Intacs intracorneal ring segments (Addition Technology, Inc.). SETTING Departments of Ophthalmology and Pathology, Hospital Pellegrin, Bordeaux, France. METHODS This retrospective study included 8 keratoconic, contact-lens-intolerant eyes of 8 patients who had penetrating keratoplasty (PKP) after removal of Intacs inserts because of a poor refractive outcome or insert extrusion. Light microscopy was performed on all specimens after conventional staining. Immunohistochemistry was performed to identify cell types located next to the tunnel using AE1/AE3 cytokeratins, CD34, vimentin, collagen IV, and alpha-smooth muscle actin monoclonal antibodies. RESULTS Conventional histology showed hypoplasia of the epithelium immediately surrounding the channel. There was no evidence of an inflammatory response or foreign-body granuloma. Keratocyte density was decreased above and below the tunnel, and collagen IV synthesis was seen in the scar area. All samples stained negatively with alpha-smooth muscle actin, indicating that myofibroblasts were not present. These changes were no longer visible when PKP was performed more than 6 months after Intacs explantation. CONCLUSIONS Intacs induced keratocyte apoptosis, probably through a switch to a collagenous synthetic phenotype. Although histological changes seem to be entirely reversible after implant removal, longer follow-up is necessary to determine whether they accelerate corneal thinning and keratoconus progression via apoptosis and release of metalloprotease.
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Affiliation(s)
- Sépideh Samimi
- Ophthalmology and Pathology Departments, Hospital Pellegrin, Bordeaux, France
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Kymionis GD, Siganos CS, Tsiklis NS, Anastasakis A, Yoo SH, Pallikaris AI, Astyrakakis N, Pallikaris IG. Long-term follow-up of Intacs in keratoconus. Am J Ophthalmol 2007; 143:236-244. [PMID: 17184717 DOI: 10.1016/j.ajo.2006.10.041] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2006] [Revised: 10/15/2006] [Accepted: 10/16/2006] [Indexed: 10/23/2022]
Abstract
PURPOSE To evaluate long-term follow-up of Intacs microthin prescription inserts (Addition Technology, Inc, Fremont, California, USA) for the management of keratoconus. DESIGN A long-term (five years) retrospective, follow-up study. METHODS Seventeen eyes of 15 patients with keratoconus ages 24 to 52 years (mean age +/- standard deviation [SD], 34.0 +/- 10.5 years) who had completed five years of follow-up (mean follow-up +/- SD, 67.2 +/- 7.5 months; range, 58 to 78 months) were included. Two Intacs segments of 0.45-mm thickness were inserted in the cornea of each eye, aiming at embracing the keratoconus area to try to achieve maximal flattening. RESULTS No late postoperative complications occurred in this series of patients. At five years, the spherical equivalent error was statistically significantly reduced (pre-Intacs, mean +/- SD -5.54 +/- 5.02 diopters [D]; range, -12.50 to 3.63 D; -3.02 +/- 2.65 D; range, -8.25 to 1.88 D) (P = .01). Pre-Intacs uncorrected visual acuity (UCVA) was 20/50 or worse in all eyes (range, counting fingers to 20/50), whereas, at the last follow-up examination, 10 (59%) of 17 eyes had UCVA of 20/50 or better (range, counting fingers to 20/32). Six eyes (35%) maintained the pre-Intacs best spectacle-corrected visual acuity (BSCVA) and one eye lost 3 lines of BSCVA, whereas the rest of the 10 eyes (59%) experienced a gain of one up to 8 lines. CONCLUSIONS After five years, intracorneal ring segments implantation improved UCVA, BSCVA, and refraction in the majority of the keratoconus patients. There was no evidence of progressive sight-threatening complications in this study.
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Affiliation(s)
- George D Kymionis
- Department of Ophthalmology, Institute of Vision and Optics, University of Crete, Crete, Greece.
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Katsoulis K, Sarra GM, Schittny JC, Frueh BE. Bilateral Central Crystalline Corneal Deposits Four Years After Intacs for Myopia. J Refract Surg 2006; 22:910-3. [PMID: 17124888 DOI: 10.3928/1081-597x-20061101-13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To report a case of bilateral central crystalline keratopathy in the anterior stroma occurring 4 years after Intacs implantation. METHODS A 45-year-old woman underwent bilateral uncomplicated Intacs implantation for myopia. The postoperative course was uneventful. However, between 3 and 4 years after surgery, the patient developed central opacifications of the anterior stroma in both eyes, reducing best spectacle-corrected visual acuity. RESULTS Intacs were explanted. Confocal microscopy, electron microscopy of the explanted ring segments, and microbiology studies were performed. Opacities were still detectable at the slit-lamp microscope up to 8 months after explantation. CONCLUSIONS This is the first report on central corneal opacifications after Intacs implantation for myopia. The opacities could be the result of chronic metabolic stress or the beginning of lipid-like changes in another more central corneal localization.
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Kymionis GD, Tsiklis NS, Pallikaris AI, Kounis G, Diakonis VF, Astyrakakis N, Siganos CS. Long-term Follow-up of Intacs for Post-LASIK Corneal Ectasia. Ophthalmology 2006; 113:1909-17. [PMID: 17074560 DOI: 10.1016/j.ophtha.2006.05.043] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 04/14/2006] [Accepted: 05/26/2006] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE To report long-term follow-up of Intacs microthin prescription inserts for the management of post-LASIK corneal ectasia. DESIGN Long-term (5 years), retrospective, nonrandomized study. PARTICIPANTS Eight eyes of 5 patients with post-LASIK corneal ectasia (3 men and 2 women) ages 31 to 54 years (mean age+/-standard deviation [SD], 41.60+/-9.24 years) who had completed 5 years of follow-up (mean follow-up +/- SD, 60.1+/-4.9 months; range, 57-68 months). INTERVENTION Two Intacs segments, inserted in the usual fashion, were used for low myopia correction (1 each nasally and temporally), with thickness based on the residual refraction of the patients. MAIN OUTCOME MEASURES Manifest refraction, uncorrected and best spectacle-corrected visual acuity, patient satisfaction, topography, and confocal microscopy analysis. RESULTS No intraoperative or late postoperative complications occurred in this series of patients. At 5 years, the SE error was statistically significantly reduced (pre-Intacs mean+/-SD, -5.47+/-2.66 diopters [D]; range, -11.50 to -3.00 D) to -2.56+/-3.44 D (range, -9.50 to 1.5 D; P = 0.01). At the end of the first postoperative year, refractive stability was obtained and remained stable during the follow-up period with no significant changes between the interval meantime (P>0.05). Pre-Intacs uncorrected visual acuity was 20/100 or worse in all eyes (range, counting fingers-20/100), whereas at the last follow-up examination, 6 (75%) of 8 eyes had uncorrected visual acuity of 20/40 or better (range, counting fingers-20/25). Two eyes (25%) maintained the pre-Intacs best spectacle-corrected visual acuity, whereas the rest of the eyes (6 eyes; 75%) experienced a gain of 1 or 2 lines. At the end of the first postoperative year, uncorrected and best-spectacle corrected visual acuity and topographic stability were obtained and were shown to have remained stable during the follow-up period with no significant changes between the interval meantime. Lamellar channel deposits were observed in confocal microscopy at or adjacent to the intrastromal ring segment. CONCLUSIONS Refractive stability was maintained for up to 5 years in the treatment of post-LASIK corneal ectasia after Intacs implantation. There was no evidence of progressive time-dependent corneal ectasia, late regression, or sight-threatening complications in this study.
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Affiliation(s)
- George D Kymionis
- Department of Ophthalmology, Institute of Vision and Optics, University of Crete, Medical School, Crete, Greece.
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Ly LT, McCulley JP, Verity SM, Cavanagh HD, Bowman RW, Petroll WM. Evaluation of intrastromal lipid deposits after intacs implantation using in vivo confocal microscopy. Eye Contact Lens 2006; 32:211-5. [PMID: 16845269 DOI: 10.1097/01.icl.0000194530.68528.14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To assess the structure and location of intrastromal lipid deposits after implantation of Intacs by using in vivo confocal microscopy. METHODS Seven eyes of six patients were examined by in vivo confocal microscopy 5 years (n = 6) or 2 months (n = 1) after uncomplicated implantation of Intacs for the correction of mild myopia. Selected images from all corneal layers were qualitatively evaluated for structural changes, with special attention paid to areas surrounding the Intacs implants. RESULTS In the peripheral cornea of eyes examined 5 years after surgery, epithelial and endothelial cell layers appeared normal. Tandem scanning confocal microscopy showed stromal haze surrounding the implants in all eyes examined, but no keratocyte activation was seen. Reflective amorphous or crystalline structures consistent with lipid deposition were detected in all eyes with long-term implantation of Intacs. Deposits were localized to the inner and outer edges of Intacs segments and to the region anterior to the implant. Confocal microscopy did not show any deposits in the eye examined 2 months after surgery, although the region anterior to the implant appeared hazy and edematous. Areas central to the implant appeared normal in all eyes. CONCLUSIONS The mechanical and physiologic stresses introduced by the implantation of Intacs lead to the accumulation of lipid deposits in the extracellular matrix. By using in vivo confocal microscopy, the location and structure of these deposits can be determined.
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Affiliation(s)
- Linda T Ly
- University of Texas Southwestern Medical School, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA
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Al-Torbak A, Al-Amri A, Wagoner MD. Deep corneal neovascularization after implantation with intrastromal corneal ring segments. Am J Ophthalmol 2005; 140:926-7. [PMID: 16310478 DOI: 10.1016/j.ajo.2005.05.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2005] [Revised: 05/08/2005] [Accepted: 05/09/2005] [Indexed: 11/16/2022]
Abstract
PURPOSE To demonstrate the development of deep corneal neovascularization after intrastromal corneal ring segment (ICRS) implantation, and to demonstrate complete regression after treatment with surgical removal and anti-inflammatory therapy. DESIGN Observational case report. METHODS A 29-year-old man developed deep stromal neovascularization after ICRS implantation for post-laser-assisted in situ keratomileusis ectasia that was not associated with the surgical wound. RESULTS After surgical removal of the ICRS and treatment with topical prednisolone acetate 1.0% and cyclosporine A 1.0%, complete vessel regression occurred in 2 weeks. CONCLUSIONS ICRS can induce deep corneal neovascularization that is not associated with the surgical wound. Surgical removal of the intrastromal ring and treatment with topical anti-inflammatory agents can induce vessel regression.
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Affiliation(s)
- Abdullah Al-Torbak
- Anterior Segment Division, Department of Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.
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Twa MD, Kash RL, Costello M, Schanzlin DJ. Morphologic Characteristics of Lamellar Channel Deposits in the Human Eye. Cornea 2004; 23:412-20. [PMID: 15097142 DOI: 10.1097/00003226-200405000-00021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To report the histologic characteristics of lamellar channel deposits after polymethyl methacrylate intrastromal corneal ring segments in a human eye. METHODS A 34-year-old man previously diagnosed with keratoconus received photorefractive keratectomy in his left eye that exacerbated his corneal ectasia. To delay or possibly prevent corneal transplant, the patient elected to have intrastromal corneal segments implanted in the left eye. One year later the patient underwent corneal transplant. Before transplant, lamellar channel deposits were noted on clinical microscopic examination of the left eye. We performed histologic evaluation to assess changes to the patient's excised corneal tissue and to further characterize the observed lamellar channel deposits. RESULTS Lamellar channel deposits in humans are histologically similar to our previous descriptions of deposits in rabbits. These deposits primarily consist of intracellular lipid accumulations that stain positively with oil red O and filipin but not periodic acid Schiff reaction. Immunohistochemistry of cells located in the deposit region stained positively with vimentin, suggesting that these cells were keratocytes. Stains for cytokeratins 3 and 12 and for CD68 were both negative, indicating that epithelial cells and macrophages were not present in the deposit region. CONCLUSION Lamellar channel deposits are a common clinical finding after intrastromal corneal implants. This case provides further evidence to support our hypothesis that lamellar channel deposits in humans are a tissue response to corneal implants that consist of intracellular lipid accumulations. We use this case to propose a theoretical construct for the observation of stromal lipid accumulation in response to corneal injury.
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Affiliation(s)
- Michael D Twa
- College of Optometry, The Ohio State University, Columbus, OH 43210-1240, USA.
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