RESUMEN

BACKGROUND: Investigation of the effects of conventional strabismus surgeries on corneal densitometry (CD). METHODS: Patients who had strabismus surgery between May 2022 and July 2022 were included in the study. CD software with a Pentacam device was used to determine corneal backward light scattering. CD data were analysed preoperatively and 1 month postoperatively. Patients were classified as those who had single muscle and two-muscle surgery. RESULTS: The study included 33 eyes of 28 patients. The mean age of the patients was 20.51 ± 8.22 (5-35) years. Of the eyes, 19 underwent single muscle recession surgery. Two-muscle surgeries (recession and resection combination) were performed in 14 eyes. In the 1st month postoperative, the mean CD value decreased statistically significantly only in the total cornea apical 0-2 mm zone among the layers examined (p = 0.039). There was no significant change in the other layers (p > 0.05 for all). Single-muscle and two-muscle surgery groups were similar in the amount of CD reduction, except for one layer. CONCLUSIONS: CD did not change in most of the corneal layers examined in the first month postoperatively. Single muscle and two-muscle horizontal rectus surgeries did not impair corneal clarity in the postoperative 1st month.

Asunto(s)

Fotoquimioterapia , Estrabismo , Humanos , Niño , Adolescente , Adulto Joven , Adulto , Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes , Córnea/cirugía , Músculos Oculomotores/cirugía , Estrabismo/cirugía

RESUMEN

Lumican is a keratan sulfate proteoglycan that belongs to the small leucine-rich proteoglycan family. Research has lifted the veil on the versatile roles of lumican in the pathogenesis of eye diseases. Lumican has pivotal roles in the maintenance of physiological tissue homogenesis and is often upregulated in pathological conditions, e.g., fibrosis, scar tissue formation in injured tissues, persistent inflammatory responses and immune anomaly, etc. Herein, we will review literature regarding the role of lumican in pathogenesis of inherited congenital and acquired eye diseases, e.g., cornea dystrophy, cataract, glaucoma and chorioretinal diseases, etc.

Asunto(s)

Oftalmopatías , Lumican , Humanos , Proteoglicanos Tipo Condroitín Sulfato/fisiología , Córnea/patología , Oftalmopatías/metabolismo , Oftalmopatías/patología , Sulfato de Queratano/fisiología , Proteoglicanos/fisiología

RESUMEN

This study aimed to assess clinical application of the Scheimpflug corneal tomography for objective evaluation of corneal optical density in eyes undergoing Descemet's stripping endothelial keratoplasty (DSEK). In this prospective study, 39 pseudophakic eyes with bullous keratopathy were enrolled. All eyes underwent primary DSEK. Ophthalmic examination included best corrected visual acuity (BCVA) measurement, biomicroscopy, Scheimpflug tomography, pachymetry, and endothelial cell count. All measurements were taken preoperatively and within a 2-year follow-up period. Gradual BCVA improvement was observed in all patients. After two years, the mean and median BCVA values were 0.18 logMAR. A decrease in central corneal thickness was noted only during the first 3 months postoperatively and was followed by a gradual increase. Corneal densitometry decreased constantly and most significantly in the first 3 months postoperatively. The consecutive decrease in endothelial cell count of the transplanted cornea was most significant during the first 6 months postoperatively. Six months postoperatively, the strongest correlation (Spearman's r = -0.41) with BCVA was found for densitometry. This tendency was maintained throughout the entire follow-up period. Corneal densitometry is applicable for objective monitoring of early and late outcomes of endothelial keratoplasty, showing a higher correlation with visual acuity than pachymetry and endothelial cell density.

RESUMEN

PURPOSE: To study the effect of different soft contact lens (CL) materials during short-term wear on corneal tissue. METHODS: Twenty-two healthy participants wore both silicone hydrogel (MyDay, CooperVision) and hydrogel soft CLs (Biomedics 1 day extra, CooperVision) for 8 h per lens. In each session, Scheimpflug images were captured before and immediately after CL removal. Images were analysed using the densitometry distribution analysis, a technique from which two parameters, α (corneal transparency) and ß (corneal homogeneity), were estimated. In addition, the central corneal thickness changes after CL wear and the influence of the CL material on corneal transparency were evaluated. RESULTS: The ß parameter (homogeneity) increased by 5% after wearing both CL materials (paired t-test, p < 0.001). However, the α parameter (transparency) only increased in half of the participants. No material was found to be more determinant in causing the corneal densitometry changes. Statistically significant but not clinically relevant changes in corneal thickness were observed. CONCLUSIONS: Biomarkers of corneal tissue integrity (α and ß) were affected by short-term soft contact lens wear. The observed changes in corneal transparency and homogeneity were not clinically relevant but support the importance of participant-material biocompatibility.

Asunto(s)

Lentes de Contacto Hidrofílicos , Humanos , Lentes de Contacto Hidrofílicos/efectos adversos

RESUMEN

AIM: To determine the influence of gaps [places where neither the donor's nor the recipient's Descemet's membrane (DM) is present] and overlaps (places where the recipient's DM is covered by the donor's DM) on the frequency of postoperative detachment of DM endothelial keratoplasty (DMEK) lamellae. METHODS: Totally 64 eyes of 64 patients with Fuchs' endothelial dystrophy or bullous keratopathy indicated for DMEK were randomly divided in two groups. The diameter of the implanted DMEK lamella was the same in both groups (8 mm), but we changed the diameter of the removed recipient DM. In the first group (32 eyes), the circular area was approximately 8.5 mm (gaps); in the second group (32 eyes), the diameter was 7.5 mm (overlaps). Postoperatively we noted all cases of detachment visible on the slit lamp and these cases we indicated for rebubbling. We also measured the uncorrected distance visual acuity (UDVA) as well as corrected distance visual acuity (CDVA) in decimal and postoperative endothelial cell density (ECD). The minimum follow-up time was 6mo. RESULTS: The number of rebubbling procedures in the entire group of patients was 13, i.e., 20.3%, with 6 eyes (18.7%) in the gap group, and 7 eyes (21.9%) in the overlap group. Lamella replacement (re-DMEK) was required in 3 (gap group) and 2 patients (overlap group), respectively. The difference between the groups was statistically insignificant. The UDVA was 0.54±0.21 in the gap group and 0.58±0.24 in the overlap group. The CDVA was 0.74±0.22 and 0.80±0.16, respectively. ECD was 1920±491 and 2149±570 cells/mm2. The small differences between both groups were not statistically significant. CONCLUSION: We do not notice any difference in the group of patients with overlaps or gaps of DM. The presence of small areas of gaps or overlaps does not affect the frequency of detachment of the DMEK lamellae.

RESUMEN

PURPOSE: Comparative analysis of optical properties of the cornea after different modifications of penetrating keratoplasty. MATERIAL AND METHODS: The study included 56 patients (56 eyes) divided into three study groups according to the surgery technique. Group I included 17 patients (17 eyes) after one-piece mushroom keratoplasty, group II - 21 patients (21 eyes) after two-piece mushroom keratoplasty and group III - 18 patients (18 eyes) after penetrating keratoplasty. In addition to standard examination methods, before surgery and in the course of the follow-up all patients underwent software-powered corneal densitometry on the anterior segment analyzer (Pentacam HR, "Oculus", Germany), as well as an assessment of the degree and regularity of postoperative astigmatism. RESULTS: Comparison of the obtained results revealed with a high degree of confidence higher values of the total specific light scattering after two-piece mushroom keratoplasty throughout the entire observation period (p<0.05). At the same time, there was no statistically significant difference in visual acuity between the three study groups (p>0.05). A statistically significant increase in the level of induced astigmatism was revealed after penetrating keratoplasty. CONCLUSION: The observed increase in light scattering after two-piece mushroom keratoplasty does not lead to a decrease in visual acuity. The interface in the optical zone of the cornea formed by a microkeratome does not affect the degree and regularity of induced astigmatism.

Asunto(s)

Astigmatismo , Trasplante de Córnea , Humanos , Queratoplastia Penetrante/efectos adversos , Astigmatismo/diagnóstico , Astigmatismo/etiología , Astigmatismo/cirugía , Córnea/diagnóstico por imagen , Córnea/cirugía , Agudeza Visual

RESUMEN

PURPOSE: To investigate whether Pentacam densitometry readings are affected by corneal tilt. METHODS: In a prospective study, the right eyes of 86 healthy participants aged 42.8 ± 20.0 years (range 18-79 years) were imaged using Scheimpflug tomography. Elevation maps were exported to calculate corneal tilt using custom-made software, and densitometry readings were acquired directly from the corneal densitometry analysis add-on to the standard software Oculus Pentacam HR. Simple mediation analysis was applied to study age as a confounding factor in the correlation between corneal tilt and corneal densitometry. RESULTS: Corneal tilt and corneal densitometry are not independent from one another because age is significantly correlated with both corneal tilt (r = 0.50, p < 0.001) and corneal densitometry (r = 0.91, p < 0.001). Only 3.8% of the correlation between tilt and densitometry operates directly, while the remaining 96.2% depends on age. CONCLUSIONS: Corneal tilt plays a role in corneal densitometry readings, even though the interaction is strongly influenced by age. Age is a well-known factor in densitometry readings that should be taken into consideration when interpreting Scheimpflug densitometry.

Asunto(s)

Córnea , Topografía de la Córnea/métodos , Densitometría/métodos , Voluntarios Sanos , Humanos , Estudios Prospectivos

RESUMEN

PURPOSE: To present a descriptive system for the elliptic demarcation area seen in keratoconus densitometry maps (obtained with a Scheimpflug tomographer) and to evaluate its suitability for clinical practice. METHODS: The subjects were 30 keratoconus patients at different stages and 20 healthy subjects. The averaged densitometry maps ('two-layers' scan, with fixed layers 120 µm and endothelium) were analysed using a system of four categories (termed 'Brightness', 'Contrast', 'Decentration' and 'Octants surrounded by a dark line') that we created to characterise the demarcation area. Four examiners (three corneal specialists and one junior resident) used the system to classify the maps. The inter-rater agreement was calculated for two subgroups: (1) clinical keratoconus patients and (2) both healthy patients and forme fruste keratoconus patients. Intra-rater agreement was also determined. RESULTS: Inter-rater agreement on classification was higher when analysing clinical keratoconus, reaching levels of substantial agreement. Despite this, only low levels of agreement were found in 'Decentration', penalized due to the skewness in the distribution of this descriptor. Almost perfect intra-rater agreement was obtained for all descriptors in the first subgroup of clinical keratoconus, whereas the agreement was generally moderate within the second subgroup of normal and forme fruste eyes. Agreement was slightly lower with the less experienced observer. At least three observers agreed on four forme fruste keratoconus eyes presenting abnormalities in the images. The observers reported that the 'Brightness' descriptor was subjective and redundant with 'Contrast'. CONCLUSIONS: The description of the area was repeatable and reproducible, and may be a valuable supplement when documenting clinical keratoconus stage and progression in daily practice. However, a minor learning curve was noticed and agreement was higher among the more experienced observers. Since the descriptor 'Brightness' was found to be subjective and redundant, it was excluded from the final proposed classification.

Asunto(s)

Queratocono , Córnea , Topografía de la Córnea , Densitometría , Humanos , Queratocono/diagnóstico , Reproducibilidad de los Resultados

RESUMEN

PURPOSE: To report surgical and corneal clarity scores (CCSs) of corneo-limbo-conjunctival transpositions (CLCTs) in a large number of canine cases. METHODS: Retrospective review of records that underwent CLCT to repair deep ulcers or perforations between 2002 and 2018. Signalment, concurrent eye disease, additional procedures, pathogenesis, medication, graft orientation, follow-up, and CCSs were recorded. RESULTS: 418 eyes of 399 dogs were included. Brachycephalics were most commonly affected, comprising 325/418 (77.75%) of the eyes. The most commonly affected breeds were Pugs, Shih Tzus, Cavalier King Charles Spaniels, and French Bulldogs, with 116/418 (27.75%), 64/418 (15.31%), 34/418 (8.13%), and 34/418 (8.13%) ulcerated eyes, respectively. Mean age at surgery was 5.5 years (range 59 days-17.7 years), and median follow-up time was 100 days (range 3 days-7.64 years). The most common etiopathogenesis was spontaneous ulceration in 205/418 eyes (49.04%) of which 191 (93.17%) occurred in brachycephalics. Primary keratoconjunctivitis sicca affected 122/418 eyes (29.19%) and injury 39/418 eyes (9.33%). Mean ulcer width was 3.5 mm (0.5-10 mm). Success rate was 97.13% (406/418 eyes). Failure end points recorded included no menace response, secondary glaucoma, and endophthalmitis. Pre-existing perforation was found in 101/418 (24.16%) of the eyes and significantly increased failure rate (P < .001). The median CCS was G3 (G0-G4), which was lower for Pugs (G2). Graft orientation affected CCS, but did not reach statistical significance. CONCLUSION: The high success rate and CCS for CLCT in dogs make it a good technique to treat deep ulcers but a less desirable outcome is anticipated when treating perforations and Pugs.

Asunto(s)

Trasplante de Córnea/veterinaria , Úlcera de la Córnea/veterinaria , Enfermedades de los Perros/cirugía , Procedimientos Quirúrgicos Oftalmológicos/veterinaria , Animales , Conjuntiva/cirugía , Conjuntiva/trasplante , Córnea/cirugía , Trasplante de Córnea/métodos , Úlcera de la Córnea/cirugía , Perros , Femenino , Limbo de la Córnea/cirugía , Masculino , Procedimientos Quirúrgicos Oftalmológicos/métodos , Cuidados Posoperatorios/veterinaria , Estudios Retrospectivos , Resultado del Tratamiento

RESUMEN

PURPOSE: To quantify normative corneal optical density (COD) values of healthy individuals and to investigate alterations in the COD in relation to their ocular and demographic characteristics. STUDY DESIGN: Prospective, cross-sectional, and observational. METHODS: In total, 588 eyes from 588 healthy participants with clear corneas were consecutively enrolled. Corneal densitometry values expressed in standardized grayscale units (GSU) from different corneal layers and zones obtained using the rotating Pentacam Scheimpflug system were analyzed. RESULTS: The mean (SD) COD over the 12-mm diameter area was 14.4 ± 2.74 GSU. A significant positive correlation was found between the participants' age and the total COD (r = 0.756, P < .001). No significant differences were found between males and females with respect to COD (P = .51). No significant correlation was found between the COD measurements and refractive error, pachymetry, and keratometry (P > .05 for all comparisons). On the other hand, COD was negatively correlated with white-to-white (WTW) corneal diameter (r = - 0.415, P < .001). Moreover, the WTW corneal diameter was correlated with the COD in any zone and layer of the cornea (P < .05 for all comparisons). CONCLUSIONS: Wide variations in COD can be detected even in corneas deemed clinically clear. Age and corneal diameter that seem to influence corneal transparency should be taken into account when evaluating corneal backscatter.

Asunto(s)

Córnea/anatomía & histología , Topografía de la Córnea/métodos , Luz , Refracción Ocular/fisiología , Dispersión de Radiación , Adolescente , Adulto , Anciano , Niño , Estudios Transversales , Densitometría , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Valores de Referencia , Agudeza Visual , Adulto Joven

RESUMEN

PURPOSE: To quantify normal corneal transparency by anterior segment optical coherence tomography (AS-OCT) by measuring the average pixel intensity. To analyze the variation in the average pixel intensity in mild and severe grades of corneal opacities. METHODS: This is an observational, cross-sectional study of 38 eyes from 19 patients with mild or severe grades of corneal opacities greater than 3 mm and a normal contralateral cornea. AS-OCT was performed centered on the opacity with a 3 mm cruciate protocol. A similar image is taken of the contralateral clear cornea in the same quadrant. The average pixel intensity was calculated in a standardized manner using MATLAB software. RESULT: The average pixel intensity of the normal cornea was 99.6 ± 10.9 [standard deviation (SD)]. The average pixel intensity of the mild and severe corneal opacities was 115.5 ± 9.1 and 141.1 ± 10.3, respectively. The differences were statistically significant. CONCLUSIONS: AS-OCT images can be used to quantify corneal transparency. Average pixel intensity is a measure that varies significantly with varying corneal opacification.

RESUMEN

BACKGROUND: Corneal densitometry, based on the Scheimpflug principle, is a useful noninvasive tool for quantitative evaluation of the optical quality of the cornea. It enables us to evaluate corneal transparency in the different corneal layers and different annuli. In this article, we discuss the basis of application of corneal densitometry measurements and summarize findings in patients with keratoconus. METHODS: This article is based on a selective literature review and analysis of own data. RESULTS: Patients with keratoconus have significant higher corneal densitometry values compared to healthy controls. Densitometry values also correlate with the extent of the disease. In the first months after corneal cross-linking (CXL), haze formation occurs and leads to a decrease in corneal transparency, thus densitometry peaks. Long-term analysis of densitometric data have shown that corneal transparency then starts to decrease after 3 to 6 months, and improves further with time. At 24 to 36 months after CXL, corneal transparency levels might achieve physiological values. CONCLUSION: Corneal transparency is reduced in patients with keratoconus. In the first months after CXL, haze formation and a reduction in corneal transparency can be observed, which subsequently improve with time.

Asunto(s)

Queratocono , Fotoquimioterapia , Colágeno , Córnea , Sustancia Propia , Topografía de la Córnea , Reactivos de Enlaces Cruzados , Densitometría , Estudios de Seguimiento , Humanos , Queratocono/diagnóstico , Fármacos Fotosensibilizantes , Riboflavina , Rayos Ultravioleta

RESUMEN

PURPOSE: To determine normative corneal densitometry values in relation to age, sex, refractive error, corneal thickness, and keratometry, measured using the Oculus Pentacam system. METHODS: Three hundred and thirty-eight healthy subjects (185 men; 153 women) with no corneal disease underwent an exhaustive ocular examination. Corneal densitometry was expressed in standardized grayscale units (GSU). RESULTS: The mean corneal densitometry over the total area was 16.46 ± 1.85 GSU. The Pearson correlation coefficient for total densitometry was r = 0.542 (p < 0.001). Statistically significant differences were found between men and women for the total area (p = 0.006), with readings of 16.22 ± 1.54 GSU and 16.60 ± 1.83 GSU, respectively. When the cornea was divided into layers of different depths, a significant correlation was found for all layers and age: r = 0.447 (p < 0.001), r = 0.563 (p < 0.001), and r = 0.520 (p < 0.001) for the anterior, central, and posterior layers, respectively. However, when the cornea was divided into concentric annuli starting from the center of the cornea, densitometry was strongly correlated only with age in the 6-10-mm annulus (p < 0.001). Neither mean keratometry nor spherical equivalent was correlated with corneal densitometry in any zone of the cornea (p > 0.05). CONCLUSIONS: This is the first report of normative corneal densitometry values in relation to keratometry, corneal thickness, and spherical equivalent measured with the latest Oculus Pentacam software. Corneal densitometry increases with age, but corneal keratometry and refractive parameters do not affect light scattering in the human cornea.

Asunto(s)

Envejecimiento/fisiología , Córnea/anatomía & histología , Densitometría/métodos , Refracción Ocular/fisiología , Adulto , Paquimetría Corneal , Topografía de la Córnea , Femenino , Humanos , Masculino , Persona de Mediana Edad

RESUMEN

The cornea represents the external part of the eye and consists of an epithelium, a stroma and an endothelium. Due to its curvature and transparency this structure makes up approximately 70% of the total refractive power of the eye. This function is partly made possible by the particular organization of the collagen extracellular matrix contained in the corneal stroma that allows a constant refractive power. The maintenance of such an organization involves other molecules such as type V collagen, FACITs (fibril-associated collagens with interrupted triple helices) and SLRPs (small leucine-rich proteoglycans). These components play crucial roles in the preservation of the correct organization and function of the cornea since their absence or modification leads to abnormalities such as corneal opacities. Thus, the aim of this review is to describe the different corneal collagens and proteoglycans by highlighting their importance in corneal transparency as well as their implication in corneal visual disorders.

Asunto(s)

Colágeno/metabolismo , Córnea/metabolismo , Proteoglicanos/metabolismo , Trastornos de la Visión/metabolismo , Animales , Córnea/patología , Córnea/fisiopatología , Humanos , Modelos Biológicos , Trastornos de la Visión/fisiopatología , Cicatrización de Heridas

RESUMEN

Establishing the postmortem interval is a very complex problem in Forensic Science despite the existence of several macro- and microscopic methods. In the case of ocular methods, most are based on an evaluation of the biochemical components of the vitreous humour 24-36h after death, but, to our knowledge, there are no studies on the relationship between lens and the postmortem interval. Since the lens is protected between the vitreous humour and the aqueous humour inside the eyeball, postmortem changes are assumed to start later in the lens. To evaluate the usefulness of using the lens to establish the postmortem interval, we examined 80 rabbit lens enucleated 24, 48, 72 and 96h after death, assessing changes in sphericity and absorbance at different wavelengths and any histological alterations. Both sphericity and absorbance were seen to decrease to a statistically significant extent, and there was a gradual loss of structure and organisation of the lens components as a function of the postmortem interval. Modifications in the lens were seen to be useful for determining the postmortem interval between 24 and 96h.

Asunto(s)

Autopsia , Cristalino , Cambios Post Mortem , Animales , Conejos , Factores de Tiempo

RESUMEN

Human corneal endothelial cells (HCEC) play a pivotal role in maintaining corneal transparency. Unlike in other species, HCEC are notorious for their limited proliferative capacity in vivo after diseases, injury, aging, and surgery. Persistent HCEC dysfunction leads to sight-threatening bullous keratopathy with either an insufficient cell density or retrocorneal membrane due to endothelial-mesenchymal transition (EMT). Presently, the only solution to restore vision in eyes inflicted with bullous keratopathy or retrocorneal membrane relies upon transplantation of a cadaver human donor cornea containing a healthy corneal endothelium. Due to a severe global shortage of donor corneas, in conjunction with an increasing trend toward endothelial keratoplasty, it is opportune to develop a tissue engineering strategy to produce HCEC grafts. Prior attempts of producing these grafts by unlocking the contact inhibition-mediated mitotic block using trypsin-EDTA and culturing of single HCEC in a bFGF-containing medium run the risk of losing the normal phenotype to EMT by activating canonical Wnt signaling and TGF-ß signaling. Herein, we summarize our novel approach in engineering HCEC grafts based on selective activation of p120-Kaiso signaling that is coordinated with activation of Rho-ROCK-canonical BMP signaling to reprogram HCEC into neural crest progenitors. Successful commercialization of this engineering technology will not only fulfill the global unmet need but also encourage the scientific community to re-think how cell-cell junctions can be safely perturbed to uncover novel therapeutic potentials in other model systems.

RESUMEN

PURPOSE: To investigate Descemet graft (DG) detachment rate after Descemet membrane endothelial keratoplasty (DMEK) in relation to DG position. METHODS: A total of 175 consecutive pseudophakic eyes that underwent DMEK (175 eyes for Fuchs endothelial dystrophy) from September 2009 through February 2014 at the Tübingen Eye Hospital DG position were studied retrospectively by surgical video at the end of an operation. A group of 45 eyes showed a decentration of the DG with a stromal gap of ≥1.5 mm over at least 3 clock hours between the descematorhexis edge and the DG. DG detachment was documented at a mean follow-up of 13.9 ± 3.7 months after surgery. DG detachment was defined as a detachment of 20 % or more of the DG surface area. Various donor characteristics and patient characteristics were analyzed. RESULTS: The best spectacle-corrected visual acuity (BCVA) in the group of eyes with central well-positioned DG differed significantly from those of eyes with decentered DG. The preoperative BCVA in the central well-positioned DG group was 0.63 ± 0.40 logMAR, and in the decentered DG group 0.91 ± 0.51 logMAR (P < 0.001). The postoperative BCVA in the group of eyes with central well-positioned DG was 0.12 ± 0.11 logMAR, and in the group with decentered DG 0.23 ± 0.29 logMAR (P < 0.001). Endothelial cell density and patient characteristics such as age, gender, and intraocular pressure did not differ significantly between the two groups. The group of eyes with central well-positioned DG showed DG detachment in 12 %; the group with decentered DG findings had DG detachment in 87 % (P < 0.001) at the 12 month follow up. CONCLUSION: The present findings demonstrate the importance of central well-positioned DG and the relation of disease severity. Central well-positioned DG may reduce the incidence of DG detachment. Overlapping of the donor DG and the host Descemet membrane seems to be responsible for DG detachment. One possible way to enhance graft adhesion could be a larger descematorhexis, which avoids an overlapping. The second possible way could be not waiting too long for surgery to reduce disease severity.

Asunto(s)

Lámina Limitante Posterior/patología , Queratoplastia Endotelial de la Lámina Limitante Posterior/efectos adversos , Endotelio Corneal/patología , Distrofia Endotelial de Fuchs/cirugía , Rechazo de Injerto/etiología , Anciano , Anciano de 80 o más Años , Recuento de Células , Femenino , Rechazo de Injerto/epidemiología , Supervivencia de Injerto , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Grabación en Video , Agudeza Visual

RESUMEN

Corneal stroma contains an extracellular matrix of orthogonal lamellae formed by parallel and equidistant fibrils with a homogeneous diameter of ~35 nm. This is indispensable for corneal transparency and mechanical functions. However, the mechanisms controlling corneal fibrillogenesis are incompletely understood and the conditions required for lamellar stacking are essentially unknown. Under appropriate conditions, chick embryo corneal fibroblasts can produce an extracellular matrix in vitro resembling primary corneal stroma during embryonic development. Among other requirements, cross-links between fibrillar collagens, introduced by tissue transglutaminase-2, are necessary for the self-assembly of uniform, small diameter fibrils but not their lamellar stacking. By contrast, the subsequent lamellar organization into plywood-like stacks depends on lysyl aldehyde-derived cross-links introduced by lysyl oxidase activity, which, in turn, only weakly influences fibril diameters. These cross-links are introduced at early stages of fibrillogenesis. The enzymes are likely to be important for a correct matrix deposition also during repair of the cornea.

Asunto(s)

Proteínas Aviares/metabolismo , Colágeno/metabolismo , Sustancia Propia/metabolismo , Proteínas de Unión al GTP/metabolismo , Proteína-Lisina 6-Oxidasa/metabolismo , Transglutaminasas/metabolismo , Aminopropionitrilo/farmacología , Animales , Proteínas Aviares/química , Técnicas de Cultivo de Célula , Células Cultivadas , Embrión de Pollo , Colágeno/química , Sustancia Propia/citología , Sustancia Propia/embriología , Inhibidores Enzimáticos/farmacología , Matriz Extracelular/metabolismo , Matriz Extracelular/ultraestructura , Fibroblastos/citología , Fibroblastos/metabolismo , Fibroblastos/ultraestructura , Proteínas de Unión al GTP/antagonistas & inhibidores , Proteínas de Unión al GTP/química , Microscopía Electrónica de Transmisión , Microscopía Inmunoelectrónica , Proteína Glutamina Gamma Glutamiltransferasa 2 , Proteína-Lisina 6-Oxidasa/antagonistas & inhibidores , Transglutaminasas/antagonistas & inhibidores , Transglutaminasas/química

RESUMEN

Objective:Through research of corneal transparency and related influential factors,the authors try to look for some clinical variety regulations after penetrating keratoplasty(PKP) in order to enhance the rate of surgery success.Methods:104 blind patients due to corneal disease (107 eyes) undergone PKP were followed up on months 1,3,6,12,18,24 and 36.Clarity of cornea,corneal endothelial cells and all kinds of complications were recorded besides regular examinations.Results:Grafts were transparent in 82 of 107 eyes on month 1(76.6%),in 69 of 90 eyes on months 6 (76.7%),in 51 of 81 eyes on months 12(63%),in 26 of 40 eyes on months 12 (65%) after PKP.Corrected vision were improved especially in patients of grafts transparency.Vision of patients with transparent grafts were more than 0.1 in 67 of 82 patients(82%) on month 1,in 59 of 63 patients(94%) on months 3,in 66 of 69 patients(96%) on months 6.Conclusion:PKP is an important method to corneal disease blind patients.Rejection was the major cause affecting graft transparency.