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, β=0.36] and duration [F(1.83)=13, P=0.001, β=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.

Nano-polymer-dispersed liquid crystal as phase modulator for a tunable vertical-cavity surface-emitting laser at 1.55 mum

We demonstrate what we believe is the first nonmechanical tunable vertical-cavity surface-emitting laser operating in the C band. This was achieved as a result of the combination of an InGaAs quantum well structure with a 6lambda thickness tunable index nano-polymer-dispersed liquid-crystal material. Experimental results exhibited a potential tunable range close to 10 nm, in the preliminary version, and excellent single mode locking due to the side-mode suppression ratio (more than 20 dB) over the whole spectral range. Another decisive advantage, compared to mechanical solutions, was the tuning response time of a few tens of microseconds (>30 micros) to scan the full spectral range (10 nm), making this device appropriate for some access network functions, as well as being robust and low cost. The voltage values are the main limitation to wavelength range extension. We present a first version of the device optically pumped. The next version will be electrically pumped as required for the access network applications targeted here.