AIMS: To investigate the concordance between the corneal power determined by various approaches with two tomographers (MS-39® and Galilei G6®) and the clinical history method (CHM) in patients undergoing photorefractive surgery with excimer laser for myopic errors. MATERIAL AND METHODS: Prospective cohort study. Patients undergoing keratorefractive surgery, and having pre- and postoperative keratometries, and tomographies, were included. RESULTS: In 90 eyes, the differences in the power estimated by the CHM and the one determined by four approaches with the corneal tomographers, which included measurements of the posterior cornea, did not show statistically significant differences in their averages. However, the 95% limits of agreement were very wide. After obtaining regression formulas to adjust the values of these four variables, the results of the agreement analysis were similar. CONCLUSION: Although certain values either directly determined or derived from measurements with the Galilei® and MS-39®corneal tomographers, approximated the estimated value of postoperative corneal power according to the CHM, due to the amplitude of their limits of agreement, these calculations must be taken with care, because they may not be accurate in a given eye.
- Klíčová slova
- corneal power, corneal tomography, clinical history method, refractive surgery,
- MeSH
- dospělí MeSH
- fotorefrakční keratektomie MeSH
- lasery excimerové terapeutické užití MeSH
- lidé MeSH
- mladý dospělý MeSH
- myopie * chirurgie patofyziologie diagnostické zobrazování MeSH
- prospektivní studie MeSH
- refrakce oka MeSH
- rohovka * diagnostické zobrazování chirurgie patologie patofyziologie MeSH
- rohovková topografie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Refractive surgery with excimer laser has been a very common surgical procedure worldwide during the last decades. Currently, patients who underwent refractive surgery years ago are older, with a growing number of them now needing cataract surgery. To establish the power of the intraocular lens to be implanted in these patients, it is essential to define the true corneal power. However, since the refractive surgery modified the anterior, but not the posterior surface of the cornea, the determination of the corneal power in this group of patients is challenging. This article reviews the different sources of error in finding the true corneal power in these cases, and comments on several approaches, including the clinical history method as described originally by Holladay, and a modified version of it, as well as new alternatives based on corneal tomography, using devices that are able to measure the actual anterior and posterior corneal curvatures, which have emerged in recent years to address this issue.
- Klíčová slova
- corneal power, Refractive surgery, clinical history method, corneal tomography, refractive surgery,
- MeSH
- laserová modelace rohovky pod rohovkovou lamelou * MeSH
- lasery excimerové * terapeutické užití MeSH
- lidé MeSH
- refrakce oka MeSH
- rohovka chirurgie MeSH
- rohovková topografie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
PURPOSE: The goal of our study is to find an optimal approach to the preparation and preservation of corneal stromal tissue. We want to compare different methods of corneal stromal tissue creation and storage to optimize the efficacy of this process under the conditions of an eye bank. After we find the most suitable method to create a safe high quality product, we want to prove the possibility of using a single donor cornea for more than one patient. We would also like to verify the feasibility of making more corneal lenticules after the removal of a corneal endothelium for DMEK transplantation. METHODS: We provided morphological (histology, scanning electron microscope) and microbiological analysis in order to compare different methods of corneal lenticule and corneal stromal lamellae preparation and preservation. We also tested the surgical handling of the tissue to secure a safe manipulation of the tissue for clinical use. We compared two methods of corneal lenticule preparation: microkeratome dissection and femtosecond laser. As methods of preservation, we tested hypothermia, cryopreservation at -80 degrees Celsius in DMSO (dimethyl sulfoxide) and storage at room temperature with glycerol. Some intrastromal lenticules and lamellae in each group were previously irradiated with gamma radiation of 25 kGy (KiloGray). RESULTS: Corneal stromal lamellae prepared with a microkeratome have a smoother cut - side surface compared to lamellae prepared with a femtosecond laser. Femtosecond laser preparation caused more irregularities on the surface and we detected more conglomerates of the fibrils, while lamellae made with microkeratome had more sparse network. Using femtosecond laser, we were able to make more than five lenticules from a single donor cornea. Gamma irradiation led to damage of collagen fibrils in corneal stroma and a loss of their regular arrangement. Corneal tissue stored in glycerol showed collagen fibril aggregates and empty spaces between fibrils caused by dehydration. Cryopreserved tissue without previous gamma irradiation showed the most regular structure of the fibrils comparable to storage in hypothermia. CONCLUSION: Our results suggest that formation of a corneal lenticule lamellae by microkeratome results in smoother corneal lenticules, while being much cheaper than formation by femtosecond laser. Gamma irradiation of 25 kGy caused damage of the collagen fibres as well as their network arrangement, which correlated with loss of transparency and stiffer structure. These changes impair possible surgical utilisation of gamma irradiated corneas. Storage in glycerol at room temperature and cryopreservation had similar outcomes and we believe that both methods are appropriate and safe for further clinical use .
- Klíčová slova
- Corneal lenticule implantation, Corneal stromal lamella, Corneal tissue cryopreservation, Corneal tissue gamma-irradiation, Corneal tissue preparation, Effective corneal tissue utilization,
- MeSH
- dimethylsulfoxid MeSH
- glycerol * MeSH
- hypotermie * MeSH
- kolagen MeSH
- lidé MeSH
- rohovka chirurgie MeSH
- stroma rohovky chirurgie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- dimethylsulfoxid MeSH
- glycerol * MeSH
- kolagen MeSH
Corneal stromal lenticule is a part of corneal stroma, which can be created by manual dissection, by femtosecond laser from the donor cornea, but chiefly it is a waste product of a refractive procedure ReLex SMILE (Small Incision Lenticule Extraction). Corneal lenticule has a huge potential in corneal surgery. In recent years, many studies have been published to show the possibility to use this tissue to treat corneal defects, as well as in refractive surgery. Thanks to the quantity of lenticules which arise every day during SMILE operations, this tissue is much more accessible than any other kind of corneal tissue. According to the experience with lenticule implantation in animal models, or even human patients, lenticule implantation is considered safe, reversible method, which is not associated with immune rejection or other severe complications. However, the crucial step before the process of lenticule implantation, is proper preservation of this tissue. Donor corneal tissue containing endothelium is usually preserved in hypothermia and then usable maximally for two weeks. Newer methods such as organ culture storage and use of a sterile cornea prolong the time of usability of the tissue. The possibilities for corneal lenticule storage are theoretically wider thanks to the fact, that we do not need to preserve fragile cellular structures. Besides the storage in hypothermia, other preserving methods such as cryopreservation and storage after decellularization have been tested. This review aimed to examine the current literature that describes possible methods of corneal lenticule preservation. A comprehensive search was created based on articles published in English on PubMed.gov, Cochranelibrary.com and Scopus.com using following keywords: corneal lenticule preservation, corneal lenticule storage, cold storage corneal lenticule, corneal lenticule cryopreservation till 2020.
- Klíčová slova
- Cold storage corneal lenticule, Corneal lenticule cryopreservation, Corneal lenticule implantation, Corneal lenticule preservation, Corneal lenticule storage, Keratophakia,
- MeSH
- hypotermie * MeSH
- kryoprezervace MeSH
- lidé MeSH
- rohovka chirurgie MeSH
- rohovkový endotel MeSH
- stroma rohovky * chirurgie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
PURPOSE: Neurotrophic keratopathy (NK) is a degenerative corneal disease caused by damage to the trigeminal innervation due to a decrease in corneal sensitivity or complete anaesthesia. Impaired corneal innervation leads to morphological and metabolic disorders of the epithelium. In addition, it also leads to the development of recurrent or persistent epithelial defects in corneal ulcers, which may progress to stromal lysis and corneal perforation. One possible solution for severe NK is reinnervation of the anaesthetic cornea (corneal neurotization) using the supraorbital nerve and an autologous sensory nerve graft (indirect neurotization). This article presents the results of corneal neurotization in a young male patient with persistent epithelial defects and corneal ulcers due to corneal denervation. RESULTS: A 22-year-old man with a history of neurosurgery for astrocytoma of the cerebellum and trunk on the right side at the age of 2 years, was observed for postoperative paresis of the right facial nerve with lagophthalmos in his childhood. The presence of asymptomatic dysfunction of the right trigeminal nerve was also noted. At the age of 22 years, after right eyeball contusion, the vision of the right eye decreased and a persistent epithelial defect developed, followed by corneal ulceration. Due to the exhaustion of therapeutic options in a young patient with corneal anaesthesia, the cornea was reinnervated via the contralateral supraorbital nerve using an autologous sural nerve graft. Five months after the surgery, the sensitivity of the cornea of the right eye began to recover. After amniotic membrane transplantation, the extensive epithelial defect healed, and the opaque corneal stroma gradually cleared up. CONCLUSION: The reinnervation of the anaesthetic cornea (corneal neurotization) using the supraorbital nerve and the autologous sensory nerve graft represents a new solution for severe NK treatment. The severe corneal condition in our patient healed after the surgery.
- Klíčová slova
- corneal anaesthesia/hypoesthesia, corneal neurotization, n. suralis, n. trigeminus, neurotrophic keratopathy,
- MeSH
- dítě MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- nemoci rohovky * komplikace chirurgie MeSH
- nemoci trojklaného nervu * komplikace chirurgie MeSH
- nervový transfer * MeSH
- předškolní dítě MeSH
- regenerace nervu MeSH
- rohovka chirurgie MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- předškolní dítě MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
The Purpose of present study was to investigate the effect of riboflavin/ultraviolet-A-induced collagen cross-linking (CXL) on central cornea, limbus and intraocular pressure (IOP). This was an animal experimental study. The right corneas of 10 rabbits were ultraviolet-A irradiated (3 mW/cm2 for 30 minutes) after de-epithelialization and instillation of 0.1% riboflavin / 20% Dextran drops. Left corneas served as controls. Samples were examined histologically one month postoperatively. Before and after treatment, IOP measurements were recorded bilaterally. At central cornea of eyes underwent CXL keratocyte repopulation, normal arrangement of collagen fibres and a statistically significant change in fibres diameter were detected, compared to controls. At limbus area, there were not any significant histological differences after CXL. There was no statistically significant difference between pre- and postoperative IOP in all eyes.
- Klíčová slova
- Cornea, Corneal Crosslinking, Intraocular pressure, Limbus,
- MeSH
- fotosenzibilizující látky farmakologie MeSH
- kolagen chemie ultrastruktura MeSH
- králíci MeSH
- limbus corneae účinky léků účinky záření chirurgie ultrastruktura MeSH
- nitrooční tlak * účinky léků účinky záření MeSH
- reagencia zkříženě vázaná farmakologie MeSH
- riboflavin farmakologie MeSH
- rohovka účinky léků účinky záření chirurgie ultrastruktura MeSH
- ultrafialové záření * MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- fotosenzibilizující látky MeSH
- kolagen MeSH
- reagencia zkříženě vázaná MeSH
- riboflavin MeSH
PURPOSE: To assess the impact of Acanthamoeba keratitis (AK) and amniotic membrane transplantation (AMT) in corneal explants on presence of two multifunctional endogenous lectins, i.e. galectins-1 and -7. METHODS: Ten corneal explants from AK patients (five with previous AMT and five controls without this treatment) and seven specimens of disease-free control cornea were processed by indirect fluorescent immunohistochemistry. RESULTS: Immunostaining for both galectins was obtained in the epithelium, stroma and the endothelial layer of all controls, with the strongest positivity in the epithelium. Significantly decreased intensity for galectin-1 was recorded in the epithelium of corneal explants from patients with AK and AMT. The signal for galectin-7 was significantly decreased in the epithelium of AK patients and normalized after AMT. CONCLUSIONS: AMT has a marked impact on presence of the two galectins in opposite directions, encouraging complete profiling for this family of endogenous effectors.
- Klíčová slova
- Agglutinin, cornea, immunohistochemistry, keratoplasty, lectin,
- MeSH
- akantamébová keratitida metabolismus chirurgie MeSH
- amnion transplantace MeSH
- biologické krytí * MeSH
- biologické markery metabolismus MeSH
- dospělí MeSH
- galektin 1 MeSH
- galektiny metabolismus MeSH
- imunohistochemie MeSH
- keratoplastika perforující metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- oční infekce parazitární diagnóza metabolismus chirurgie MeSH
- rohovka metabolismus chirurgie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
- práce podpořená grantem MeSH
- Názvy látek
- biologické markery MeSH
- galektin 1 MeSH
- galektiny MeSH
- LGALS7 protein, human MeSH Prohlížeč
PURPOSE: The purpose of this study was the simulation of the implantation of intrastromal corneal-ring segments for patients with keratoconus. The aim of the study was the prediction of the corneal curvature recovery after this intervention. METHODS: Seven patients with keratoconus diagnosed and treated by implantation of intrastromal corneal-ring segments were enrolled in the study. The 3D geometry of the cornea of each patient was obtained from its specific topography and a hyperelastic model was assumed to characterize its mechanical behavior. To simulate the intervention, the intrastromal corneal-ring segments were modeled and placed at the same location at which they were placed in the surgery. The finite element method was then used to obtain a simulation of the deformation of the cornea after the ring segment insertion. Finally, the predicted curvature was compared with the real curvature after the intervention. RESULTS: The simulation of the ring segment insertion was validated comparing the curvature change with the data after the surgery. Results showed a flattening of the cornea which was in consonance with the real improvement of the corneal curvature. The mean difference obtained was of 0.74 mm using properties of healthy corneas. CONCLUSIONS: For the first time, a patient-specific model of the cornea has been used to predict the outcomes of the surgery after the intrastromal corneal-ring segments implantation in real patients.
- Klíčová slova
- Biomechanical simulation, Cornea, Intrastromal ring segments, Keratoconus,
- MeSH
- analýza metodou konečných prvků MeSH
- biomechanika MeSH
- keratokonus chirurgie MeSH
- lidé MeSH
- mechanické jevy * MeSH
- počítačové modelování podle konkrétního pacienta * MeSH
- protézy a implantáty * MeSH
- rohovka chirurgie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
AIMS: To report the histological findings in two AlphaCor artificial corneas explanted following complications,to compare the mechanism of biointegration and/or failure of the device and the correlation with clinical histories. METHODS: The first patient was diagnosed with optic deposits and corneal melting during the late postoperative period and required the removal of the device. The second patient experienced injury with penetration of the device 5 months after implantation. The explanted devices embedded within the corneal tissues were processed for pathological analysis at the John A. Moran Eye Center, University of Utah, Salt Lake City, USA. Histologic findings were compared with earlier histological results from animal studies and human case series and correlated with clinical histories. RESULTS: Both devices demonstrated normal skirt porosity. Light microscopic examination of the specimens disclosed adequate biointegration - colonization of the peripheral skirt with cellular elements present within the pores of the skirt. In the first patient (specimen 1) epithelial ingrowth was observed between the peripheral skirt and the posterior surface of the specimen, with partial extrusion of the device in that area. In the second case (specimen 2) the central, optic component of the device was missing. CONCLUSION: Histologic findings of the AlphaCor skirt were consistent with earlier animal studies and human cases series reports. These findings confirm the occurrence of biointegration. Epithelial ingrowth and scattered chronic mononuclear inflammatory cells were observed in the area of partial extrusion in the patient with a history of melting prior to explantation.
- MeSH
- biokompatibilní materiály škodlivé účinky MeSH
- epitelové buňky patologie MeSH
- leukocyty mononukleární patologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- odstranění implantátu MeSH
- protézy a implantáty škodlivé účinky MeSH
- rohovka * chirurgie MeSH
- selhání protézy * MeSH
- senioři MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
- práce podpořená grantem MeSH
- Názvy látek
- biokompatibilní materiály MeSH
The purpose of this study was to investigate whether rabbit bone marrow-derived mesenchymal stem cells (MSCs) effectively decrease alkali-induced oxidative stress in the rabbit cornea. The alkali (0.15 N NaOH) was applied on the corneas of the right eyes and then rinsed with tap water. In the first group of rabbits the injured corneas remained untreated. In the second group MSCs were applied on the injured corneal surface immediately after the injury and eyelids sutured for two days. Then the sutures were removed. In the third group nanofiber scaffolds seeded with MSCs (and in the fourth group nanofibers alone) were transferred onto the corneas immediately after the injury and the eyelids sutured. Two days later the eyelid sutures were removed together with the nanofiber scaffolds. The rabbits were sacrificed on days four, ten or fifteen after the injury, and the corneas were examined immunohistochemically, morphologically, for the central corneal thickness (taken as an index of corneal hydration) using an ultrasonic pachymeter and by real-time PCR. Results show that in untreated injured corneas the expression of malondialdehyde (MDA) and nitrotyrosine (NT) (important markers of lipid peroxidation and oxidative stress) appeared in the epithelium. The antioxidant aldehyde dehydrogenase 3A1 (ALDH3A1) decreased in the corneal epithelium, particularly in superficial parts, where apoptotic cell death (detected by active caspase-3) was high. (In control corneal epithelium MDA and NT are absent and ALDH3A1 highly present in all layers of the epithelium. Cell apoptosis are sporadic). In injured untreated cornea further corneal disturbances developed: The expressions of matrix metalloproteinase 9 (MMP9) and proinflammatory cytokines, were high. At the end of experiment (on day 15) the injured untreated corneas were vascularized and numerous inflammatory cells were present in the corneal stroma. Vascular endothelial growth factor (VEGF) expression and number of macrophages were high. The results obtained in injured corneas covered with nanofiber scaffolds alone (without MSCs) or in injured corneas treated with MSCs only (transferred without scaffolds) did not significantly differ from the results found in untreated injured corneas. In contrast, in the injured corneas treated with MSCs on nanofiber scaffolds, ALDH3A1 expression remained high in the epithelium (as in the control cornea) and positive expression of the other immunohistochemical markers employed was very low (MMP9) or absent (NT, MDA, proinflammatory cytokines), also similarly as in the control cornea. Corneal neovascularization and the infiltration of the corneal stroma with inflammatory cells were significantly suppressed in the injured corneas treated with MSCs compared to the untreated injured ones. The increased central corneal thickness together with corneal opalescency appearing after alkali injury returned to normal levels over the course of ten days only in the injured corneas treated with MSCs on nanofiber scaffolds. The expression of genes for the proinflammatory cytokines corresponded with their immunohistochemical expression. In conclusion, MSCs on nanofiber scaffolds protected the formation of toxic peroxynitrite (detected by NT residues), lowered apoptotic cell death and decreased matrix metalloproteinase and pro-inflammatory cytokine production. This resulted in reduced corneal inflammation as well as neovascularization and significantly accelerated corneal healing.
- Klíčová slova
- alkali-induced oxidative stress, central corneal thickness, immunohistochemistry, rabbit cornea, rabbit mesenchymal stem cells, real-time PCR,
- MeSH
- alkálie toxicita MeSH
- chemické popálení patologie chirurgie MeSH
- hojení ran MeSH
- králíci MeSH
- mezenchymální kmenové buňky cytologie MeSH
- modely nemocí na zvířatech MeSH
- nanovlákna terapeutické užití MeSH
- oxidační stres * MeSH
- poranění rohovky MeSH
- rohovka patologie chirurgie MeSH
- tkáňové podpůrné struktury * MeSH
- transplantace mezenchymálních kmenových buněk metody MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Názvy látek
- alkálie MeSH
