Cataract surgery with femtosecond lasers

AbstractCataract surgery with femtosecond lasers is approaching its practical application in ophthalmology. These lasers, working in the near infrared wavelength (1030nm) can penetrate the transparent and even opaque tissues of the anterior segment of the eye, with limitations related to vessels and mineral opacities. Femtosecond lasers, guided by image systems can precisely outline the anatomy of the anterior segment of the eye, acting in a very precise way, performing corneal incisions, capsulorhexis, softening and breaking of the nucleus, which are essential steps in cataract surgery.In this article we summarize the four technologies available and approaching commercial application in the coming future. The main differences between the systems are based on the diagnostic imaging techniques, which might either be based on optical coherence tomography or the Scheimpflug principles. One model (the Technolas Femtec 520 F custom lens, 20/10 Perfect Vision), offers the possibility of combined use in corneal and intraocular surgery.While clinical studies are being performed with all of them, and most probably becoming available on the market during 2011 and 2012, the main problem of this emerging technology is its practical application as the increase in costs will affect their availability in the market of cataract surgery.Research is needed to confirm the practicality and the advantages of femtosecond laser cataract surgery over conventional surgery. Meanwhile, a new path for the future of cataract surgery is opening

La teletermografía dinámica en oftalmología : estudio del patrón termográfico de normalidad y del valor de la técnica en el diagnóstico diferencial tumoral

Tesis Univ.Complutense.Depto. de Inmunología, Oftalmología y ORLFac. de MedicinaTRUEProQuestpu

Desarrollo de modelos experimentales de prótesis de córnea humanizada autóloga

La regeneración corneal es una etapa esencial en la restitución de la normalidad anatómica en las patologías debilitantes de la córnea. El objetivo en esta tesis doctoral es el desarrollo de biomateriales transportadores de células autólogas humanas de tipo pluripotencial, con la finalidad de promover la integración de dichos biomateriales y regenerar el estroma en las córneas estructuralmente debilitadas. En una primera fase analizamos las propiedades físicas in vitro de injertos porosos de 90[my]m de espesor de polietilacrilato (PEA) y estroma corneal humano descelularizado, además de analizar la capacidad de proliferación, infiltración y adhesión de células madre derivadas del tejido adiposo humano (ADASC) sobre los mismos. En una segunda fase se estudió el comportamiento in vivo de estos dos tipos de implantes con y sin colonización celular mediante un ensayo controlado y triple enmascarado, usando un modelo experimental de conejo albino neozelandés. Los implantes se introdujeron dentro de bolsillos instraestromales disecados manualmente y se realizó un seguimiento completo de 3 meses, donde se analizaron clínicamente la inyección conjuntival, trasparencia y vascularización corneal. Tras la eutanasia de los conejos se realizó un análisis histológico e histoquímico con el objetivo de evaluar la supervivencia de las ADASC y su diferenciación en queratocitos adultos. La prótesis de PEA con un 10% de hidroxietilacrilato redujo drásticamente su tasa de extrusión, pudiendo ser utilizado como scaffold en futuros modelos de queratoprótesis. Las láminas de córnea humana descelularizada con posterior recelularización demostraron una óptima biointegración en el estroma corneal en ausencia de respuesta inflamatoria alguna, además de permitir una mejor supervivencia y diferenciación de las células madre en comparación con las membranas de PEA. Este modelo de trasplante lamelar mediante descelularización con posterior recelularización con células madre extraoculares permite la obtención de injertos lamelares funcionalizados autólogos a partir de córneas alogénicas

Desarrollo de modelos experimentales de prótesis de córnea humanizada autóloga

La regeneración corneal es una etapa esencial en la restitución de la normalidad anatómica en las patologías debilitantes de la córnea. El objetivo en esta tesis doctoral es el desarrollo de biomateriales transportadores de células autólogas humanas de tipo pluripotencial, con la finalidad de promover la integración de dichos biomateriales y regenerar el estroma en las córneas estructuralmente debilitadas. En una primera fase analizamos las propiedades físicas in vitro de injertos porosos de 90[my]m de espesor de polietilacrilato (PEA) y estroma corneal humano descelularizado, además de analizar la capacidad de proliferación, infiltración y adhesión de células madre derivadas del tejido adiposo humano (ADASC) sobre los mismos. En una segunda fase se estudió el comportamiento in vivo de estos dos tipos de implantes con y sin colonización celular mediante un ensayo controlado y triple enmascarado, usando un modelo experimental de conejo albino neozelandés. Los implantes se introdujeron dentro de bolsillos instraestromales disecados manualmente y se realizó un seguimiento completo de 3 meses, donde se analizaron clínicamente la inyección conjuntival, trasparencia y vascularización corneal. Tras la eutanasia de los conejos se realizó un análisis histológico e histoquímico con el objetivo de evaluar la supervivencia de las ADASC y su diferenciación en queratocitos adultos. La prótesis de PEA con un 10% de hidroxietilacrilato redujo drásticamente su tasa de extrusión, pudiendo ser utilizado como scaffold en futuros modelos de queratoprótesis. Las láminas de córnea humana descelularizada con posterior recelularización demostraron una óptima biointegración en el estroma corneal en ausencia de respuesta inflamatoria alguna, además de permitir una mejor supervivencia y diferenciación de las células madre en comparación con las membranas de PEA. Este modelo de trasplante lamelar mediante descelularización con posterior recelularización con células madre extraoculares permite la obtención de injertos lamelares funcionalizados autólogos a partir de córneas alogénicas

Relationship between Corneal Morphogeometrical Properties and Biomechanical Parameters Derived from Dynamic Bidirectional Air Applanation Measurement Procedure in Keratoconus

The morphogeometric analysis of the corneal structure has become a clinically relevant diagnostic procedure in keratoconus (KC) as well as the in vivo evaluation of the corneal biomechanical properties. However, the relationship between these two types of metrics is still not well understood. The current study investigated the relationship of corneal morphogeometry and volume with two biomechanical parameters: corneal hysteresis (CH) and corneal resistance factor (CRF), both provided by an Ocular Response Analyzer (Reichert). It included 109 eyes from 109 patients (aged between 18 and 69 years) with a diagnosis of keratoconus (KC) who underwent a complete eye examination including a comprehensive corneal topographic analysis with the Sirius system (CSO). With the topographic information obtained, a morphogeometric and volumetric analysis was performed, defining different variables of clinical use. CH and CRF were found to be correlated with these variables, but this correlation was highly influenced by corneal thickness. This suggests that the mechanical properties of KC cornea contribute only in a partial and limited manner to these biomechanical parameters, being mostly influenced by morphogeometry under normal intraocular pressure levels. This would explain the limitation of CH and CRF as diagnostic tools for the detection of incipient cases of KC.This publication was carried out in the framework of the Thematic Network for Co-Operative Research in Health (RETICS) reference number RD12/0034/0007 and RD16/0008/0012, financed by the Carlos III Health Institute—General Subdirection of Networks and Cooperative Investigation Centers (R&D&I National Plan 2008–2011) and the European Regional Development Fund (FEDER). The author David P. Piñero has been supported by the Ministry of Economy, Industry, and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471

Safety and visual outcomes following posterior chamber phakic intraocular lens bilensectomy

To evaluate the safety, efficacy, refractive outcomes and causes for bilensectomy (phakic intraocular lens - pIOL - explantation with cataract surgery and pseudophakic intraocular lens implantation) in patients previously implanted with posterior chamber pIOLs. This multi-center retrospective study included 87 eyes of 55 patients who underwent bilensectomy for posterior chamber pIOL with a follow up time of 12 months. The uncorrected and best corrected distance visual acuities (UDVA, CDVA), endothelial cell density before and after bilensectomy were assessed, as well as the cause of bilensectomy and intra or postoperative complications. There was a statistically significant improvement in uncorrected and best corrected visual acuities after bilensectomy (p = 0.00). The main reason for bilensectomy was cataract development (93.1% of the cases), followed by miscalculation of lens size, and corneal edema. The endothelial cell count remained stable without a statistically significant change after surgery (p = 0.67). The refractive efficacy index was 0.8, none of the patients lost lines of CDVA after surgery, 73% of the patients were within ±1 D (spherical equivalent) of the target refraction. Intraoperative complications were one posterior capsule rupture with the intraocular lens (IOL) implanted in the sulcus, and 3 eyes required the use of pupil expanders for adequate pupil dilation. Postoperatively, one eye developed retinal detachment. The three pIOLs models explanted were the Implantable Collamer Lens (ICL), Implantable Phakic Contact Lens (IPCL) and the Phakic Refractive Lens (PRL). Good safety and visual outcomes were observed 1 year after bilensectomy for posterior chamber phakic intraocular lenses (PC pIOLs). There were few intra and postoperative complications and there was no significant endothelial cell loss after the bilensectomy procedure

Postoperative Corynebacterium macginleyi endophthalmitis

A 72-year-old man with chronic endophthalmitis who received steroid treatment for 3 months came to our center. Sterile endophthalmitis after cataract extraction had been diagnosed. Aqueous samples including smears, classic cultures, and polymerase chain reaction were taken for microbiological study. Amplified DNA was sequenced to identify the pathogen. Polymerase chain reaction amplification was positive for bacteria. Sequence analysis showed Corynebacterium macginleyi as the causal agent in 48 hours. The culture and smear stains from the ocular samples were negative. The patient was successfully treated with vancomycin. Polymerase chain reaction and subsequent DNA-typing were useful in detecting the microorganisms that caused the chronic endophthalmitis

Iterative Methods for the Biomechanical Evaluation of Corneal Response. A Case Study in the Measurement Phase

The number of corneal surgeries steadily grew in recent years and boosted the development of corneal biomechanical models. These models can contribute to simulating surgery by reducing associated risks and the need for secondary interventions due to ectasias or other problems related to correcting other diseases. Biomechanical models are based on the geometry obtained with corneal topography, which is affected by intraocular pressure and material properties. Knowledge of stress distribution in the measurement phase is a key factor for improving the accuracy of in silico mechanical models. In this work, the results obtained by two different methods: prestress method and displacements method were compared to evaluate the stress and strain distribution in a general geometric model based on the Navarro eye geometry and two real corneal geometries. The results show that both methods are equivalent for the achievement of the stress distribution in the measurement phase. Stress distribution over the corneal geometry in the measurement phase is a key factor for accurate biomechanical simulations, and these simulations could help to develop patient-specific models and reduce the number of secondary interventions in clinical practice.This publication was carried out in the framework of the Thematic Network for Co‐Operative Research in Health (RETICS) reference number RD12/0034/0007 and RD16/0008/0012, financed by the Carlos III Health Institute—General Subdirection of Networks and Cooperative Investigation Centers (R&D&I National Plan 2008–2011) and the European Regional Development Fund (FEDER). The author David P. Piñero was supported by the Ministry of Economy, Industry, and Competitiveness of Spain within the program Ramón y Cajal, RYC‐2016‐20471

Calidad de visión y satisfacción del paciente usuario de pantallas de visualización de datos tras cirugía

Función visual[ES] dad de vida y satisfacción de los trabajadores usuarios de pantallas de visualización de datos (PVD) que se asocia a la mejora de la función visual tras queratomileusis in situ con láser excimer (LASIK). MÉTODOS: Estudio observacional y longitudinal en una población de 96 pacientes intervenidos de cirugía refractiva con láser excimer según técnica LASIK mediante aplicación de un cuestionario construído al efecto aplicado antes y después de cirugía por un observador independiente. RESULTADOS: Agudeza visual y refracción ocular han mejorado tras LASIK, siendo el índice de eficacia de 1.1. La sensibilidad al contraste tras cirugía mejora en todas las frecuencias (6 c/g, 3 c/g y 1 c/g) en el ojo derecho. Mientras que en el ojo izquierdo no hay diferencias significativas. La calidad de visión con y sin corrección es mejor tras LASIK (significativa p < 0.05). Volverían a intervenirse y recomendarían este procedimiento quirúrgico a otros pacientes el 84.38 % de pacientes. CONCLUSIONES: Los resultados muestran que el LASIK mejora la a función visual y la calidadde vida de estos pacientes.[EN] PURPOSE: To evaluate the influence in quality of vision and satisfaction of video display terminal (VDT) users related to improvement of visual functions following excimer laser in situ keratomileusis (LASIK). METHODS: Longitudinal and observational study in a population of 96 patients that underwent LASIK using a questionnaire made for that, applied before and after surgery by an independent observer. RESULTS: Visual acuity and ocular refraction have improved after LASIK, being the efficiency index 1.1. Contrast sensitivity postoperative improved at all spatial frequencies in the right eye (6 c/g, 3 c/g and 1 c/). While in the left eye there were no significant differences. Quality of vision with and without correction is also better after LASIK (p < 0.05). And 84.38 % of patients would repeat themselves and recommend this surgery to other patients. CONCLUSIONS: The results show that LASIK improves visual function and quality of life of patients.N

Morphogeometric analysis for characterization of keratoconus considering the spatial localization and projection of apex and minimum corneal thickness point

This work evaluates changes in new morphogeometric indices developed considering the position of anterior and posterior corneal apex and minimum corneal thickness (MCT) point in keratoconus. This prospective comparative study included 440 eyes of 440 patients (age, 7–99 years): control (124 eyes) and keratoconus (KC) groups (316 eyes). Tomographic information (Sirius®, Costruzione Strumenti Oftalmici, Italy) was treated with SolidWorks v2013, creating the following morphogeometric parameters: geometric axis–apex line angle (GA–AP), geometric axis–MCT line angle (GA–MCT, apex line–MCT line angle (AP–MCT), and distances between apex and MCT points on the anterior (anterior AP–MCTd) and posterior corneal surface (posterior AP–MCTd). Statistically significant higher values of GA–AP, GA–MCT, AP–MCT and anterior AP–MCTd were found in the keratoconus group (p ≤ 0.001). Moderate significant correlations of corneal aberrations (r ≥ 0.587, p < 0.001) and corneal thickness parameters (r ≤ −0.414, p < 0.001) with GA–AP and AP–MCT were found. Anterior asphericity was found to be significantly correlated with anterior and posterior AP–MCTd (r ≥ 0.430, p < 0.001). Likewise, GA–AP and AP–MCT showed a good diagnostic ability for the detection of keratoconus, with optimal cutoff values of 9.61° (sensitivity 85.5%, specificity 80.3%) and 18.08° (sensitivity 80.5%, specificity 78.7%), respectively. These new morphogeometric indices allow a clinical characterization of the 3-D structural alteration occurring in keratoconus, with less coincidence in the spatial projection of the apex and MCT points of both corneal surfaces. Future studies should confirm the potential impact on the precision of these indices of the variability of posterior corneal surface measurements obtained with Scheimpflug imaging technology.This publication has been carried out in the framework of the Thematic Network for Co-Operative Research in Health (RETICS), reference number RD16/0008/0012, financed by the Carlos III Health Institute–General Subdirection of Networks and Cooperative Investigation Centers (R&D&I National Plan 2013–2016) and the European Regional Development Fund (FEDER). The author David P. Piñero has been supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471