Lesões na córnea: incidência e fatores de risco em Unidade de Terapia Intensiva

Patients hospitalized in the Intensive Care Unit (ICU) may present risk for corneal injury due to sedation or coma. This study aimed to estimate the incidence of corneal injuries; to identify the risk factors and to propose a risk prediction model for the development of corneal injury, in adult patients, in an intensive care unit of a public hospital. This is a one year, prospective cohort study with 254 patients. The data were analyzed using descriptive statistics, univariate and logistic regression. Of the 254 patients, 59.4% had corneal injuries and the mean time to onset was 8.9 days. The independent variables that predispose to risk for punctate type corneal injury were: duration of hospitalization, other ventilatory support device, presence of edema and blinking less than five times a minute. The Glasgow Coma Scale and exposure of the ocular globe were the variables related to corneal ulcer type corneal injury. The injury frequencies were punctate type (55.1%) and corneal ulcers (11.8%). Risk prediction models for the development of punctate and corneal ulcer type corneal injury were established.Pacientes internados en Unidad de Terapia Intensiva (UTI) pueden presentar riesgo de lesión en la córnea debido a la sedación o al coma. Este estudio tuvo por objetivo estimar la incidencia de las lesiones en la córnea; identificar los factores de riesgo y proponer un modelo de predicción de riesgo para el desarrollo de lesión en la córnea, en pacientes adultos, en Unidad de Terapia Intensiva, de un hospital público. Estudio de cohorte prospectivo de un año con 254 pacientes. Los datos fueron analizados por estadística descriptiva, univariada y de regresión logística. De los 254 pacientes, 59,4% tuvieron lesión en la córnea y el tiempo promedio para su aparición fue de 8,9 días. Las variables independientes que predisponen al riesgo de lesión en la córnea tipo punteada fueron: tiempo de internación, otro dispositivo de asistencia ventilatoria, presencia de edema y parpadeo de ojos menor que cinco veces por minuto. La escala de coma de Glasgow y la exposición del globo ocular fueron las variables relacionadas a la lesión en la córnea del tipo úlcera de córnea. Las lesiones fueron del tipo punteada (55,1%) y úlceras de córnea (11,8%). Modelos de predicción de riesgo para lesiones en la córnea del tipo punteada y úlcera fueron establecidos.Pacientes internados em unidade de terapia intensiva (UTI) podem apresentar risco para lesão na córnea devido à sedação ou coma. Este estudo teve por objetivo estimar a incidência das lesões na córnea, identificar os fatores de risco e propor modelo de predição de risco para o desenvolvimento de lesão na córnea, em pacientes adultos, em unidade de terapia intensiva, de um hospital público. É estudo de coorte prospectiva de um ano, com 254 pacientes. Os dados foram analisados por estatística descritiva, univariada e de regressão logística. Dos 254 pacientes, 59,4% tiveram lesão na córnea e o tempo médio para o seu aparecimento foi de 8,9 dias. As variáveis independentes que predispõem ao risco para lesão na córnea, tipo puntacta, foram: tempo de internação, outro dispositivo de assistência ventilatoria, presença de edema e piscar de olhos menor que cinco vezes por minuto. Escala de coma de Glasgow e exposição de globo ocular foram as variáveis relacionadas à lesão na córnea do tipo úlcera de córnea. As lesões foram do tipo puntacta (55,1%) e úlceras de córnea (11,8%). Modelos de predição de risco para lesões na córnea do tipo puntacta e úlcera foram estabelecidos

Causes of congenital corneal opacities and their management in a tertiary care center.

PURPOSE: To evaluate causes and management of congenital corneal opacities (CCO) diagnosed in a tertiary care eye center and to compare the data with a previous study at the same institution. METHODS: Computerized medical records in all patients with congenital corneal opacities diagnosed in the Cornea Service at Wills Eye Hospital (Philadelphia, PA) between January 1, 2007, and December 31, 2015, were retrospectively reviewed. Children aged 12 years and younger at the first visit were included in the study. Patients\u27 demographics, ocular diagnosis, laterality, associated ocular abnormalities, other ocular surgery performed prior or subsequent to the first visit, and their treatment were extracted from the medical records. RESULTS: A total of 77 eyes in 56 patients were examined. The mean age at presentation was 32.8 ± 44.2 months, with the mean follow-up period of 26.7 ± 30.1 months. The most frequent diagnosis was Peters anomaly (53.2%), followed by limbal dermoid (13.0%), aniridia with glaucoma and microphthalmos (6.5%), sclerocornea and congenital glaucoma (5.2%), idiopathic (3.9%), Axenfeld-Rieger anomaly and Hurler syndrome (2.6%), and microcornea (1.3%). Primary keratoplasty was performed in 26 eyes, with the outcome rate in the clear cornea of 76.0% during the follow-up. CONCLUSION: Peters anomaly is the most common cause of congenital corneal opacities encountered at our institution. Penetrating keratoplasty is the most frequent choice of corneal surgery to treat congenital corneal opacities. Additional interventions during penetrating keratoplasty were moderately positively correlated with graft failure. This study also shows the rates of some etiologies of that changed over the recent decades in our tertiary care Cornea Service. Although Peters anomaly remains the most common presenting reason for congenital corneal opacities, its rate appears to be increasing over the recent decade. Congenital corneal opacities due to birth trauma, which is one of the preventable causes, were observed in a previous study in our clinic; however, no new cases were noted in this study

Evolució dels instruments de mesura de paràmetres de la còrnia

La córnea constituye la primera superficie transparente en contacto con el medio externo y actúa como primera lente del sistema visual. Juntamente con la esclera y la lágrima protege al ojo de los agentes externos potencialmente peligrosos y da gran parte del poder refractivo total del sistema visual. Actualmente en el mundo clínico es imprescindible saber los parámetros de la córnea tales como radios, diámetros y grosores para poder realizar tareas que van desde la adaptación de lentes de contacto hasta todo tipo de operaciones corneales. El objetivo de este trabajo se centra en conocer los instrumentos de medida de la córnea, los principios ópticos que son utilizados en cada caso, la aplicación clínica de los resultados obtenidos y la evolución de estos instrumentos hasta la actualidad. Para conseguir estos objetivos es imprescindible saber cuáles son las diferentes partes y funciones de la córnea, de manera que previamente y de una forma introductoria, se darán a conocer todos estos conceptos. Con estos objetivos lo que se quiere conseguir es dar a conocer como extraer la información más relevante de las medidas de los parámetros corneales y lo que nos permiten hacer actualmente los diferentes tipos de topógrafos que existen, siempre desde un punto de vista clínico

Corneal biomechanical properties : Measurement, modification and simulation

Esta tesis aborda la medición de las propiedades biomecánicas de la córnea. Se desarrollaron técnicas para medir la rigidez de la córnea in vitro con el fin de estudiar el comportamiento de la córnea como una función de diferentes factores (tales como la hidratación, la geometría, la presión intraocular y la rigidez de la córnea). Los datos experimentales se utilizaron para construir modelos numéricos capaces de reproducir la respuesta biomecánica observada de la córnea. Se aplicaron modelos numéricos para recuperar los parámetros biomecánicos de mediciones de deformación in vivo y para estudiar el efecto de la implantación de segmentos de anillos intraestromales. En particular, se utilizaron el método de inflación en ojos enteros y botones córneales, la extensiometría bídimensional, un soplo de aire combinado con tomografía de coherencia óptica (OCT), microscopía de Brillouin y OCT-vibrografía para las mediciones experimentales. Para el análisis numérico, se construyeron modelos de elementos finitos para estudiar la inflación de ojos enteros y botones córneales, la respuesta de la córnea después de un soplo de aire, el comportamiento del ojo bajo vibración y los cambios refractivos después de la implantación de anillos intraestromales. This thesis addresses the measurement of the corneal biomechanical properties. Techniques were developed to measure the corneal stiffness in vitro in order to study the corneal behavior as a function of different factors (such as hydration, geometry, intraocular pressure, corneal stiffness). Experimental data were used to build numerical models, which were able to reproduce the observed biomechanical response of the cornea. Numerical models were applied to retrieve biomechanical parameters from in vivo deformation measurements and to study the outcome with implantation of intrastromal ring segments. In particular whole-eye / corneal inflation, 2D extensiometry, an air-puff technique combined with optical coherence tomography (OCT), Brillouin microscopy and OCT-vibrography were used for the experimental measurements. For the numerical analysis, finite element models were built for eye inflation, corneal response following an air-puff, ocular vibration behavior and refractive changes after ICRS implantation

A comparison of two conjunctival rotation autograft techniques in primary pterygium surgery.

PURPOSE: To compare the effects of 90° and 180° conjunctival rotational autograft (CRA) techniques used in primary pterygium surgery. METHODS: Forty-five patients were included in this retrospective study. Visual acuity (VA), corneal topography, and auto-refractometer measurements, as well as detailed biomicroscopic examinations, were performed preoperatively and postoperatively. During surgery, the pterygium tissue was excised then rotated 90° in Group 1 and180° in Group 2, after which it was sutured to the bare sclera. Pterygium recurrence was defined as corneal invasion ≥1 mm. RESULTS: Group 1 consisted of 21 patients with a mean age of 45.1 ± 11.8 years, while Group 2 comprised 24 patients with a mean age of 47.9 ± 13.8 years. The pterygia in Group 1 were graded as more advanced than those in Group 2. A similar number of recurrences were observed in Group 1 (14.3%) and in Group 2 (16.7%). There was no statistically significant difference in terms of the preoperative and postoperative VA and astigmatism values between the two groups. There was a statistically significant improvement in the postoperative VA and astigmatism values in Group 1 and in the postoperative astigmatism values in Group 2. Although postoperative redness was more common in Group 1, no statistically significant difference was found between the groups. CONCLUSION: BothCRA techniques can be successful in patients for whom it is desirable to avoid a conjunctival autograft and for patients without high cosmetic expectations

Propriedades biomecânicas locais em uma córnea modelada usando elementos finitos prevê surgimento de ceratocone

PURPOSE: The ability to predict and understand which biomechanical properties of the cornea are responsible for the stability or progression of keratoconus may be an important clinical and surgical tool for the eye-care professional. We have developed a finite element model of the cornea, that tries to predicts keratoconus-like behavior and its evolution based on material properties of the corneal tissue. METHODS: Corneal material properties were modeled using bibliographic data and corneal topography was based on literature values from a schematic eye model. Commercial software was used to simulate mechanical and surface properties when the cornea was subject to different local parameters, such as elasticity. RESULTS: The simulation has shown that, depending on the corneal initial surface shape, changes in local material properties and also different intraocular pressures values induce a localized protuberance and increase in curvature when compared to the remaining portion of the cornea. CONCLUSIONS: This technique provides a quantitative and accurate approach to the problem of understanding the biomechanical nature of keratoconus. The implemented model has shown that changes in local material properties of the cornea and intraocular pressure are intrinsically related to keratoconus pathology and its shape/curvature.OBJETIVOS: A possibilidade de prever e entender quais propriedades biomecânicas da córnea podem ser responsáveis pelo progresso ou estabilização do ceratocone pode ser uma importante ferramenta clínica e cirúrgica para o oftalmologista. Neste trabalho foi desenvolvido um modelo em elementos finitos da córnea, o qual prevê o surgimento de deformações semelhantes ao ceratocone e sua evolução baseado em propriedades biomecânicas do tecido corneano. MÉTODOS: As propriedades biomecânicas da córnea foram modeladas segundo dados disponíveis na literatura para olhos esquemáticos. Softwares comerciais foram usados para simular propriedades de superfície e material quando a córnea foi submetida a diferentes parâmetros locais de elasticidade. RESULTADOS: As simulações conduzidas aqui mostraram que, dependendo do formato inicial da córnea, mudanças nas propriedades locais do material para diferentes pressões intraoculares, induzem uma protuberância localizada e um aumento significativo de curvatura quando comparado ao restante da córnea. CONCLUSÕES: A técnica apresentada aqui permite o estudo mais preciso e quantitativo da natureza biomecânica do ceratocone. O modelo implementado demonstrou que mudanças locais de propriedades biomecânicas relacionais à elasticidade para uma mesma pressão intraocular, estão intrinsecamente relacionados ao surgimento e evolução de deformações que podem ter relação direta com o ceratocone

Efeitos agudos do cloridrato de ropivacaína na ultraestrutura das células endoteliais da córnea de equinos : estudo ex vivo

The objective of this study was to evaluate the acute effects of ropivacaine hydrochloride on the corneal endothelium of horses. Forty-eight eyes were obtained from a commercial slaughterhouse and were randomly divided into three groups. In group A, the corneal endothelium was exposed to 0.75% ropivacaine hydrochloride for 60 seconds. In group B, the corneal endothelium was exposed to 0.75% ropivacaine hydrochloride for 15 minutes. In group C, the corneal endothelium was exposed to a balanced saline solution for 60 seconds. Afterwards, all samples were prepared for evaluation with scanning electron microscopy. Random electromicrographs were obtained from each sample. The images were analysed and, with the aid of software, areas with no endothelial cells were measured. The average endothelial loss, expressed as a percentage in relation to the total area, of the samples in group A was 5.28%. The average endothelial loss of samples from group B, expressed as a percentage in relation to the total area, was 20.39%. The damage to the corneal endothelium was significantly greater in group B compared to groups A and C. It was possible to conclude that 0.75% ropivacaine hydrochloride induced acute damage to corneal endothelium cells.Objetivou-se avaliar os efeitos agudos do cloridrato de ropivacaína no endotélio da córnea de equinos. Quarenta e oito olhos de equinos foram divididos aleatoriamente em três grupos. No grupo A o endotélio da córnea foi exposto a cloridrato de ropivacaína a 0,75% por 60 segundos. No grupo B o endotélio da córnea foi exposto a cloridrato de ropivacaína a 0,75% por 15 minutos. No grupo C o endotélio da córnea foi exposto à solução salina balanceada por 60 segundos. As amostras foram preparadas para avaliação com microscopia eletrônica de varredura. Eletromicrografias eletrônicas de varredura foram obtidas aleatoriamente de cada amostra. As imagens foram analisadas e, com o auxílio de um programa para morfometria foram medidas as áreas sem células endoteliais. A perda endotelial média foi expressa em porcentagem em relação à área total das amostras do grupo A foi de 5,28%. A perda endotelial média de amostras do grupo B foi expressa em porcentagem em relação à área total, foi de 20,39%. O dano ao endotélio da córnea foi significativamente maior no grupo B, comparado aos grupos A e C. O cloridrato de ropivacaína a 0,75% induziu dano agudo nas células do endotélio da córnea de equinos

Perfil epidemiológico dos pacientes transplantados de córnea em Santa Catarina, 2009

Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Dapartamento de Clínica Cirúrgica

Transplante de córnea na infância

Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Dapartamento de Clínica Cirúrgica