A5064798469- Ophthalmology and Visual Impairment Studies
- Corneal surgery and disorders
- Glaucoma and retinal disorders
- Ocular Surface and Contact Lens
- Visual perception and processing mechanisms
- CCD and CMOS Imaging Sensors
- Retinal and Optic Conditions
- Gaze Tracking and Assistive Technology
- Tactile and Sensory Interactions
- Advanced Optical Imaging Technologies
- Retinal and Macular Surgery
- Corneal Surgery and Treatments
- Adaptive optics and wavefront sensing
- Ocular and Laser Science Research
- Vascular Malformations Diagnosis and Treatment
- Intraocular Surgery and Lenses
- Astro and Planetary Science
- Connexins and lens biology
- Retinal Imaging and Analysis
- Retinal Diseases and Treatments
- Atmospheric Ozone and Climate
- Ocular Diseases and Behçet’s Syndrome
- Ocular Infections and Treatments
- Digital Holography and Microscopy
- Safety Warnings and Signage
Universidad de Murcia
2009-2023
Harvard University
2001-2010
Smith-Kettlewell Eye Research Institute
2001-2009
Massachusetts Eye and Ear Infirmary
2001-2003
Optica
2002
A description of a Hartmann–Shack sensor to measure the aberrations human eye is presented. We performed an analysis accuracy and limitations using experimental results computer simulations. compared ocular modulation transfer function obtained from simultaneously recorded double-pass images. The following factors affecting performance were evaluated: statistical accuracy, number modes used reconstruct wave front, size microlenses, exposure time.
We evaluated the performance of a liquid-crystal spatial light modulator for static correction aberrations in human eye. By applying phase-retrieval techniques to pairs double-pass images we first estimated wave aberration eye be corrected. Then introduced opposite phase map modulator, which was placed plane conjugated with eye's pupil, and recorded point source before after aberrations. In slightly aberrated artificial clear improvement obtained correction, and, although diffraction-limited...
purpose. To determine how severe peripheral field loss (PFL) affects the dispersion of eye movements relative to head in patients walking real environments. This information should help define visual and clearance requirements for head-mounted mobility aids. methods. Eye positions were recorded five with retinitis pigmentosa who had less than 15° three normally sighted people, each varied environments more 30 minutes. The eye-position recorder was made portable by modifying a system (ISCAN,...
Purpose.: To evaluate the optical characteristics of Boston Keratoprosthesis (KPro), identify glare sources, possible control, and examine benefit implantation when fellow eye has normal vision. Methods.: Computed optical-bench-measured point spread function (PSF) sources were compared. A translucent plastic cornea was used to determine impact caused by scatter in its control with a dark-iris tinted contact lens. The effect implanted eyes measured brightness acuity test (BAT), without visual...
Purpose. An augmented-view device for patients with severely restricted peripheral visual fields (tunnel vision) was proposed, combining a see-through head-mounted display and simultaneous minified view of wide field presented as contour information. Here we create evaluate multiple implementations the concept report responses from potential users. Methods. Several prototypes using commercial off-the-shelf devices were implemented. Then they evaluated in real environments daylight at night...
An imaging polariscope has been used to analyze the spatially resolved polarization properties of living human corneas. The apparatus is a modified double-pass setup, incorporating liquid-crystal modulator in analyzer pathway. Keeping incident state fixed (first passage), we recorded series three images pupil's plane corresponding independent states unit. Azimuth and retardation at each point cornea were calculated from those images. Results show that magnitude increases along radius toward...
Both visually salient and top-down information are important in eye movement control, but their relative roles the planning of daily saccades unclear. We investigated effect peripheral vision loss on saccadic behaviors patients with tunnel (visual field diameters 7°–16°) visual search real-world walking experiments. The made up to two per second pre-saccadic blind areas, about half which had no overlap between post- views. In experiment, size background (blank or picture) did not affect...
Abstract We present laboratory measurements of the phase functions and degree linear polarization (DLP) curves a selection millimeter-sized cosmic dust analog particles. The set includes particles with similar sizes but diverse internal structure (compact porous) absorbing properties. measured are found to be in all cases very different from those micron-sized They show monotonic decrease increasing angle back- side-scattering region, reaching minimum at large angles before steep increase...
Ocular straylight has been measured by means of psychophysical methods over the years.This approach gives a functional parameter yielding straight comparison with optically defined light scattering, and pointspread-function.This is particular importance when effect intraocular lenses (IOLs) on postoperative sought.An optical system for measurements IOLs was adapted to commercial device (C-Quant, Oculus), which employs such method.The proposed modifications were validated using...
Oblique Fresnel peripheral prisms have been used for field expansion in homonymous hemianopia mobility such as walking and driving. However, limited expansion, low image quality, small eye scanning range limit their effectiveness. We developed a new oblique multi-periscopic prism using cascade of rotated half-penta prisms, which provides 42° horizontal along with 18° vertical shift, high wider range. Feasibility performance prototype 3D-printed module are demonstrated by raytracing,...
We propose a new quantitative phase microscope based on spatial filtering of the beam carrying sample-induced wavefront. A prototype built using transmissive liquid crystal display for experimental demonstration principle and preliminary results obtained with artificial biological samples are presented.
We present experimental phase functions of three types millimeter-sized dust grains consisting enstatite, quartz and volcanic material from Mount Etna, respectively. The similar sizes but different absorbing properties. measurements are performed at 527 nm covering the scattering angle range 3 to 170 degrees. measured show two well defined regions i) soft forward peaks ii) a continuous increase with side- back-scattering regions. This behavior in agreement observed for Fomalhaut HR 4796A...
"Looked-but-failed-to-see" errors are a common cause of accidents, but it has never been determined whether obstructive elements within an automobile (e.g., window posts or the interior rearview mirror) have actually obstacle to vision. This work describes technique that can easily be used determine available visual field drivers at wheel and illustrates its potential in number applications.The involves calibrating minicamera for use as device perimetry then mounting on spectacles so lies...
Patients with visual field loss frequently collide other pedestrians, the highest risk being from pedestrians at a bearing angle of 45°. Current prismatic expansion devices (≈30°) cannot cover posing and are limited by poor image quality restricted eye scanning range (<5°). A new device: multi-periscopic prism (MPP); comprising cascade half-penta prisms provides wider shifting power (45°) dramatically better (15°) is presented. Spectacles-mounted MPPs were implemented using 3D printing. The...
Abstract— Binocular head‐mounted displays (HMDs) that could be used non‐immersively produced substantial interruption of the visual field. Monocular HMDs designed to created minimal fields. The scotomata are small enough allow HMD worn in mobile situations, but inattention associated with use may cause safety concerns for some situations. A opaque display can positioned provide a see‐through functionality.
Spectacle-mounted telescopic systems are prescribed for individuals with visual impairments. Bioptic telescopes typically mounted toward the top of spectacle lens (or above frame) telescope eyepiece positioned wearer's pupil. This allows wearer to use up and down head tilt movements quickly alternate between unmagnified wide view (through carrier lens) magnified narrow field (available through eyepiece). Rejection this aid has been attributed mainly its appearance limited smaller Galilean...
Abstract The purpose of this work is to describe a versatile optoelectronic aid for low vision rehabilitation based on reconfigurable hardware. This easily adaptable diverse pathologies (with different associated processing tasks) and the progression visual impairment. platform has mobile configuration that uses see‐through head‐mounted display (Nomad). We have implemented types enhancement platform, briefly summarize here their computational costs (in terms hardware resource requirements)....
ABSTRACT Purpose Multifocal contact lenses have been growing in popularity as a modality to correct presbyopic eyes, although visual side effects such disability glare reported. The objective of this study was investigate the effect multifocal on by means ocular straylight. Methods A prospective randomized, comparative performed that included 16 subjects free pathology. Straylight measured using commercial straylight meter with natural and dilated pupil. Participants were fitted Proclear...
Measurement of the eye's wave aberrations has become fairly standard in recent years. However, most studies have not taken into account possible influence polarization state light on aberration measurements. The birefringence properties optical components, particular corneal birefringence, can be expected to an effect estimates obtained under different states for measurement light. In work described, we used a psychophysical aberrometer (the spatially resolved refractometer) measure changes...
Purpose: Amplitude of accommodation (AA) is reportedly greater for myopic eyes than hyperopic eyes. We investigated potential explanations this difference. Methods: Analytical analysis and computer ray tracing were performed on two schematic eye models axial ametropia. Using paraxial nonparaxial approaches, AA was specified the naked corrected using anterior corneal surface as reference plane. Results: Assuming that myopia due entirely to an increase in vitreous chamber depth, increases with...
Abstract An augmented‐vision device for patients with severely restricted peripheral visual field (tunnel vision) was proposed, combining a see‐through HMD and minified contour detection. Implemented commercial off‐the‐shelf (COTS) configurations were tested in real environments by Retinitis Pigmentosa normally sighted subjects.
A psychophysical approach has been designed to measure straylight from intraocular lenses (IOLs) in vitro.This uses a clinical meter (C-Quant) and an observer's eye as optical detector.Based on this, we introduced method for study of straylight-wavelength dependency IOLs.This can be used distinguish between 2 types scattering particles (small large) defined by Mie theory.Validation was performed using turbidity standard filters.Several IOLs were analyzed identify potential sources.Large...