Novel methods for subcellular in vivo imaging of the cornea with the Rostock Cornea Module 2.0

The Rostock Cornea Module transforms a confocal laser scanning ophthalmoscope into a corneal confocal laser scanning microscope. In this thesis, an improved version, the Rostock Cornea Module 2.0, and its achieved results were demonstrated. These include a concave contact cap design to attenuate eye movements to improve 3D volume reconstruction, an oscillating focal plane to improve mosaicking of the subbasal nerve plexus, the integration of simultaneous optical coherence tomography, multiwavelength corneal imaging, the clinical usage, and the automated morphological characterization

Astigmatism and Pseudoaccommodation in Pseudophakic Eyes

noAdvanced IOLs with circumferential zones of different power provide pseudoaccommodation. We investigated the potential for power variation with meridian, namely astigmatism, to provide pseudo-accommodation. With appropriate power and axis orientations, acceptable pseudo-accommodation can be achieved

Powell Lens-based Line-Scan Spectral Domain Optical Coherence Tomography for Cellular Resolution Imaging of Biological Tissues

A line-scan spectral-domain optical coherence tomography system was developed for corneal imaging. It utilizes a Powell lens to achieve a better line illumination power distribution than the conventional use of cylindrical lenses. It achieves a lateral resolution of <2.1 microns and ~4.1 microns in the x and y directions and an axial resolution of ~1.5 microns in tissue

Practical Ophthalmology

The study guide is intended to train students of higher medical educational institutions of the fourth level of accreditation on the specialty “Medicine”, interns, residents and masters. The guide is a new progressive step in teaching the discipline “Ophthalmology”

Transillumination techniques in ophthalmic imaging

In vivo imaging of the human cornea and retina is typically performed in a reflection geometry. Images are formed from light that has backscattered off corneal microstructures or backreflected from the retina. In this configuration, artifacts caused by superficial surface reflections are often encountered. These unwanted reflections can either globally overwhelm the signal or cause local glare, complicating reliable image quantification. This thesis describes a pair of alternative ophthalmic imaging techniques based instead on transmitted light, which inherently avoids these artifacts. For retinal (i.e. fundus) imaging, we describe a mesoscopic transmission imaging method, which we call transcranial fundus imaging. The method uses deeply penetrating near-infrared light delivered transcranially from the side of the head, and exploits multiple scattering to redirect a portion of the light towards the posterior eye. This unique transmission geometry simplifies absorption measurements and enables flash-free, non-mydriatic imaging as deep as the choroid. We use multispectral image sets taken with this new transillumination approach to estimate oxygen saturation in retinal blood vessels. In the cornea, we describe a new technique for non-contact phase-contrast microscopic imaging. It is based on fundus retro-reflection and back-illumination of the crystalline lens and cornea. To enhance phase-gradient contrast, we apply asymmetric illumination by illuminating one side of the fundus. The technique produces micron-scale lateral resolution across a 1-mm diagonal field of view. We show representative images of the epithelium, the subbasal nerve plexus, large stromal nerves, dendritic immune cells, endothelial nuclei, and the anterior crystalline lens, demonstrating the potential of this instrument for clinical applications

The HYPSOS optomechanical bench design

In the last years, almost all the planetary missions have included a stereo camera and a spectrograph on-board. These two instruments respectively provide stereo images and spectral information, essential data to characterize a planet's surface. HYPSOS (HYPerspectral Stereo Observing System) is a novel instrument that will be able to merge the function of the two instruments. In fact, it will produce stereo hypercubes and represent 3D data with a fourth dimension: the spectral information.openEmbargo temporaneo per motivi di segretezza e/o di proprietà dei risultati e informazioni di enti esterni o aziende private che hanno partecipato alla realizzazione del lavoro di ricerca relativo alla tes

Advances in Ophthalmology

This book focuses on the different aspects of ophthalmology - the medical science of diagnosis and treatment of eye disorders. Ophthalmology is divided into various clinical subspecialties, such as cornea, cataract, glaucoma, uveitis, retina, neuro-ophthalmology, pediatric ophthalmology, oncology, pathology, and oculoplastics. This book incorporates new developments as well as future perspectives in ophthalmology and is a balanced product between covering a wide range of diseases and expedited publication. It is intended to be the appetizer for other books to follow. Ophthalmologists, researchers, specialists, trainees, and general practitioners with an interest in ophthalmology will find this book interesting and useful

Femtosecond lasers in corneal and refractive surgery

Femtosecond lasers were introduced in ophthalmology initially for flap creation for LASIK. This thesis describes a body of work undertaken by the author exploring the possibility of using these lasers in corneal and refractive surgery. The use of the femtosecond laser in corneal and refractive surgery offered the prospect of better precision with respect to their accuracy in depth cut, and the smoothest of lamellar interface. The development of multiple laser platforms allowed us to perform comparative studies in both ex vivo/animal and clinical studies and to explore the prospect of a new refractive procedure, lenticule extraction and also lenticule re-implantation. The laser proved to be accurate in its vertical depth cutting and following optimization was able to cut a smoothe lamellar interface. The clinical study showed the laser to be safe and effective. The comparative studies showed the superiority of the lower energy femtosecond laser on IOP rise, without compromising on clinical outcomes, which were the same for both lasers. Femtosecond laser lenticule creation was optimised in animal models and then shown to be safe and efficacious in a clinical study. The wound healing benefits of an ‘all in one’ femtosecond laser procedure were evident, in both animal as well clinical studies. Lenticule reimplantation was shown to be effective in both the rabbit and monkey models. The use of the femtosecond laser is set to increase in ophthalmology. The work in this thesis has provided fundmental ex vivo, animal and clinical benefits on the the use of femtosecond lasers in corneal and refractive surgery. It has also envisioned a concept of lenticule re-implantation for future clinical use