Search results for "Adaptive optics"
showing 7 items of 37 documents
Titanium dioxide waveguides for supercontinuum generation and optical transmissions in the near-and mid-infrared
2019
International audience; We report the development of titanium dioxide-based waveguides for applications in the near-and mid-infrared. Thanks to embedded metal grating couplers, we demonstrate error free 10 Gbit/s optical transmissions at 1.55 and 2 µm. With additional management of the dispersion profile, we also demonstrate octave spanning supercontinuum in cm-long TiO2 waveguides.
Data Transmissions at 1.98 µm in cm-long SiGe Waveguides
2017
International audience; We demonstrate an error-free transmission of 10-Gbit/s optical signals along a SiGe waveguide at a wavelength of 1.98 μm. Bit error rate measurements confirm the absence of penalty during the transmission through a 2.5-cm long waveguide having a width of 2.2 μm.
Depth-of-Field of the Accommodating Eye
2014
Our eyes project information from a three-dimensional world to a basically two-dimensional surface, corresponding to the photoreceptor plane in the retina. In theory, only one plane or surface of world can be in focus at one time. However, the eye exhibits a certain tolerance to out-of-focus images, a feature that is known as depth-of-focus (DOF). The corresponding distance range in which the objects are seen “clearly” is known as depth-of-field (DOFi). Although DOF and DOFi refer to an interval of distances or a dioptric range in the image and object space, respectively, both parameters define a similar concept and are usually interchangeable. This article will mainly refer to DOFi because…
Crystalline lens response to different optical signals
2016
Es bien sabido que el ojo es capaz de cambiar su potencia con el fin de enfocar a objetos ubicados a diferentes distancias. El cambio en enfoque del ojo humano se denomina acomodación y es vital para el rendimiento visual del mismo ya que la acomodación tiene una contribución esencial para dicho rendimiento. La calidad de la imagen retiniana también influye en el rendimiento visual del ojo humano así como en la resolución de las imágenes formadas en la retina. La calidad de la imagen retiniana se describe en términos de aberraciones oculares. El objetivo de esta Tesis fue investigar la respuesta del cristalino a diferentes señales ópticas. Para lograr el objetivo del estudio se utilizaron l…
Light vergence detection in monocular and monochromatic accommodation
2017
El ojo proyecta información desde el mundo tridimensional a la retina, la cual es una superficie bidimensional. Por este motivo, teóricamente sólo objetos que se encuentren en el plano conjugado a la retina pueden ser enfocados de forma correcta y, por tanto, objetos que se encuentren por delante o por detrás del plano conjugado, serán percibidos como imágenes borrosas. Por suerte, la acomodación ocular permite al ojo joven ver objetos situados a diferentes distancias de forma nítida. Este sistema de autoenfoque se consigue gracias al cambio de potencia dióptrica experimentado por el ojo como consecuencia del cambio en la morfología del cristalino. Debido a la alta frecuencia temporal de la…
A new trifocal corneal inlay for presbyopia
2021
[EN] Corneal inlays (CIs) are the most recent surgical procedure for the treatment of presbyopia in patients who want complete independence from the use of glasses or contact lenses. Although refractive surgery in presbyopic patients is mostly performed in combination with cataract surgery, when the implantation of an intraocular lens is not necessary, the option of CIs has the advantage of being minimally invasive. Current designs of CIs are, either: small aperture devices, or refractive devices, however, both methods do not have good performance simultaneously at intermediate and near distances in eyes that are unable to accommodate. In the present study, we propose the first design of a …
High-resolution images in macular disorders
2021
Objective: This study analyzed and compared the results of adaptive optics (AO) and fundus autofluorescence (FAF) in various maculopathies. Methods: The study included four different types of maculopathy: central serous chorioretinopathy (CSC), retinitis pigmentosa (RP), Stargardt disease (STGD) and phototoxic retinopathy. In all four cases, cone mosaic and cone density were obtained using AO fundus camera. Further, the high-resolution images were compared with the FAF and optical coherence tomography (OCT) results. Results: In CSC, FAF and AO, changes could be shown in the macula even two years after the subretinal fluid resorption, as opposed to a normal OCT. The improvement of FAF and co…