Blazed photon sieve for the correction of presbyopia.

What we believe to be a new type of transparent photon sieve is presented with application for presbyopia correction. Inspired by blazed gratings, we propose to design an intracorneal implant with slanted holes. The slopes introduce a new degree of freedom, breaking the symmetry of energy distribution along the optical axis and allowing to balance the energy between near and far vision. This new implant design is presented together with the simulation, manufacturing and validation methods. The first experimental results obtained with an implant manufactured in a biocompatible material are presented confirming the potential of the approach.

Impact of virtual reality headset use on eye blinking and lipid layer thickness.

PURPOSE: Blinking plays an important role in protecting the eyes, and the use of computers has been associated with a reduction in the blink rate. The goal of this study was to evaluate the effect of a virtual reality headset on blinking and lipid layer thickness and to compare these data to those associated with a conventional desktop monitor. METHODS: Two experiments were performed to compare the effect of 20minutes of use of a virtual reality headset (FOVE) and 20minutes of use of a desktop monitor on the frequency and length of blinks (experiment 1, 15 participants) and on the thickness of the lipid layer as measured by Lipiview (experiment 2, 12 participants). RESULTS: In the first experiment, the blink rate [F(1.83)=4.3, P=0.04, ß=0.36] and duration [F(1.83)=13, P=0.001, ß=0.35] increased with time under both conditions, but no statistical difference was found between the two conditions (headset vs. desktop monitor) either for blink rate [rmANOVA F(1.11)=0.01, P=0.92; headset: 15.1 blinks, 95% CI: 12.6 to 17.6 blinks; desktop: 14.6 blinks, 95% CI: 13.6 to 15.7 blinks] or for blink duration [rmANOVA F(1.11)=4.534, P=0.06; headset: 205.75ms, 95% CI: 200.9 to 210.6ms; desktop: 202.82ms, 95% CI: 198.2 to 207.5ms]. However, strong individual variations were observed. Evaluation of simulator sickness and visual fatigue by questionnaire showed no significant differences between the two conditions (SSQ simulator sickness questionnaire: V=46, P=0.62; VFQ visual fatigue questionnaire: V=15.5, P=0.13). In the second experiment, the lipid layer thickness increased significantly after use of the VR headset [F(1.18)=11.03, P=0.004, headset: 76.2nm, desktop: 58.8nm]. CONCLUSION: In terms of recommendations, the effect of virtual reality headsets on blink duration and frequency during a moderate exposure (20minutes) is comparable to that of a conventional desktop monitor. However, the strong individual variations observed, the lack of reliable tests to evaluate this individual sensitivity, and the significant increase in lipid layer thickness in experiment 2 suggest the value of a more detailed investigation, in particular with consideration of a longer exposure time and other tear film parameters.

A laser emitting contact lens for eye tracking.

In this paper, we present the first realisation and experimentation of a new eye tracking system using an infrared (iR) laser pointer embedded into a wireless smart contact lens. We denote this contact lens prototype as the cyclops lens, in reference to the famous hero of the X-Men comics. The full eye tracker device combines the smart contact lens and its eyewear, which provides a primary source of energy and the beam detection system. We detail the assembling and encapsulation process of the main functionalities into the contact lens and present how a gaze tracking system is achieved, compared to existing conventional eye-tracking ones. Finally, we discuss future technical improvements.

Object kinetics perception in auto-stereoscopic vision.

In this paper, we study the conditions for the perception of object kinetics, produced by a multiview auto-stereoscopic system and a set of still images. We assess the capabilities and performances of such an optical system to encode complex trajectories and kinetics of objects moving in depth. In particular, we set up rules to create motions with nonuniform velocities, when obtained by motion parallax induced by the observer. We establish a link with plenoptic systems from where we derive applicable scaling rules to ensure stereoscopic vision and to provide fluid motion perception with satisfying visual comfort. Finally, we scale the optical system, thanks to obtained parameters, to emulate the perception of object motions in depth with fluid kinetics and to create impressive motion effects.

High-resolution hyperspectral imaging of the retina with a modified fundus camera.

PURPOSE: to examine the practical feasibility of developing a hyperspectral camera from a Zeiss fundus camera and to illustrate its use in imaging diabetic retinopathy and glaucoma patients. METHODS: the original light source of the camera was replaced with an external lamp filtered by a fast tunable liquid-crystal filter. The filtered light was then brought into the camera through an optical fiber. The original film camera was replaced by a digital camera. Images were obtained in normals and patients (primary open angle glaucoma, diabetic retinopathy) recruited at the Manchester Royal Eye Hospital. RESULTS: a series of eight images were captured across 495- to 720-nm wavelengths, and recording time was less than 1.6s. The light level at the cornea was below the ANSI limits, and patients judged the measurement to be very comfortable. Images were of high quality and were used to generate a pixel-to-pixel oxygenation map of the optic nerve head. Frame alignment is necessary for frame-to-frame comparison but can be achieved through simple methods. CONCLUSIONS: we have developed a hyperspectral camera with high spatial and spectral resolution across the whole visible spectrum that can be adapted from a standard fundus camera. The hyperspectral technique allows wavelength-specific visualization of retinal lesions that may be subvisible using a white light source camera. This hyperspectral technique may facilitate localization of retinal and disc pathology and consequently facilitate the diagnosis and management of retinal disease.

Self-imaging properties of polychromatic Gaussian beams: application to wavelength demultiplexing and space routing.

We propose an analytical model of the self-imaging of Gaussian beams and discuss the impact of the finite aperture and the beam truncation on the quality of the self-image reconstruction. Extension to polychromatic operation is then presented in the context of wavelength division multiplexing systems. From the first point we derive conditions for good self-imaging, compatible with the requirements of the telecommunication environment. A basic optical setup is then proposed to implement both wavelength demultiplexing and routing in a lensless configuration.