Acuité visuelle

vignette|Tableau de Snellen qui permet de mesurer l'acuité visuelle humaine. L'acuité visuelle (mesurée sur un œil, en vision de loin) est la capacité de discerner un petit objet (ou optotype) situé le plus loin possible, ce qui est équivalent à voir à une distance fixe (en général cinq mètres) un optotype sous le plus petit angle possible. Différentes formes d'acuité visuelle Le minimum visible Le minimum visible représente la visibilité binaire d'un point ou d'une ligne (vu/non vu). Un trait ou un point de fort contraste, typiquement un trait noir sur un fond blanc, peut être distingué à partir d’un diamètre apparent de 0,5 seconde d’arc. Le minimum séparable C’est la distance minimale entre 2 points distincts de contraste maximal correctement discernés. C’est la notion d’acuité visuelle commune. La minute d’arc (1′) est la référence de normalité. Cette valeur angulaire n'est pas utilisée en France, où l'on a préféré rapporter cette valeur à une fra

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Œil humain

Déficience visuelle

thumb|300px|Surface podotactile à la gare de Paris-Est Un déficient visuel est une personne dont l'acuité visuelle est faible (malvoyante), voire inférieure à 1/20 pour le meilleur œil après correctio

Œil

thumb|Œil humain. thumb|Yeux multiples d'une araignée (Maevia inclemens). thumb|Yeux composés d'une mouche (Holcocephala fusca). thumb|Les crevettes-mantes (ici Odontodactylus scyllarus) sont réputés

Sutureless ocular surface reconstruction

Basile Salmon

Corneal diseases account for eight million blind people worldwide, making up to 10% of all causes of blindness. As 80% of the information is collected by our senses, blindness is a very invalidating condition which lowers greatly patients’ quality of life. Limbal stem cell deficiency describes all the conditions involving the failure of corneal epithelium and its progressive replacement by conjunctival epithelium and the opacification of the cornea, creating ultimately a loss of vision. Restoring transparency by reconstructing the ocular surface with a healthy corneal epithelium is the only long term treatment of this condition and has been a major challenge for regenerative medicine for the past twenty years. As the understanding of corneal epithelium renewal increases, the solutions offered to restore visual acuity are improving but the long term results of techniques used so far are still poor. We describe here an attempt to fix the issue of inflammation due to sutures in the case of transplantation of limbal epithelial cells carried by an amniotic membrane, by the use of an adhesive. LYDEX, our chemically defined bioadhesive uses food additives as building blocks for the formation of an hydrogel, which has been described to be perfectly bio-compatible. Results of this study confirm the absence of immunological reaction in the presence of our hydrogel but also bring to light its potentially insufficient permeability to glucose, which combined to mechanical trauma, leads to a dramatic failure of the grafted epithelium

2010

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Design and validation of a foldable and photovoltaic wide-field epiretinal prosthesis

Marta Jole Ildelfonsa Airaghi Leccardi, Michele Bevilacqua, Naïg Aurelia Ludmilla Chenais, Laura Ferlauto, Diego Ghezzi, Samuel Charles Antoine Gilliéron, Kevin Sivula, Paola Vagni

Retinal prostheses have been developed to fight blindness in people affected by outer retinal layer dystrophies. To date, few hundred patients have received a retinal implant. Inspired by intraocular lenses, we have designed a foldable and photovoltaic wide-field epiretinal prosthesis (named POLYRETINA) capable of stimulating wireless retinal ganglion cells. Here we show that within a visual angle of 46.3 degrees, POLYRETINA embeds 2215 stimulating pixels, of which 967 are in the central area of 5 mm, it is foldable to allow implantation through a small scleral incision, and it has a hemispherical shape to match the curvature of the eye. We demonstrate that it is not cytotoxic and respects optical and thermal safety standards; accelerated ageing shows a lifetime of at least 2 years. POLYRETINA represents significant progress towards the improvement of both visual acuity and visual field with the same device, a current challenging issue in the field.

2018

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How do visual skills relate to action video game performance?

Arthur Barakat, Oh-Hyeon Choung, Aline Françoise Cretenoud, Michael Herzog

It has been claimed that video gamers possess increased perceptual and cognitive skills compared to non-video gamers. Here, we examined to which extent gaming performance in CS:GO (Counter-Strike: Global Offensive) correlates with visual performance.We tested 94 players ranging from beginners to experts with a battery of visual paradigms, such as visual acuity and contrast detection. In addition, we assessed performance in specific gaming skills, such as shooting and tracking, and administered personality traits. All measures together explained about 70% of the variance of the players’ rank. In particular, regression models showed that a few visual abilities, such as visual acuity in the periphery and the susceptibility to the Honeycomb illusion, were strongly associated with the players’ rank. Although the causality of the effect remains unknown, our results show that high-rank players perform better in certain visual skills compared to low-rank players.

2021

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MICRO-722: 3D Printing with light

Optical aspects of 3D printing technology. This includes optical systems for scanning and excitation, photopolymers, glass and other photoactive materials, and optical components fabricated with 3D printing technology.

BIOENG-448: Fundamentals of neuroengineering

Neuroengineering is at the frontier between neuroscience and engineering: understanding how the brain works allows developing engineering applications and therapies of high impact, while the design of new measurement and data analysis techniques contributes to advance our knowledge about the brain.

BIO-480: Neuroscience: from molecular mechanisms to disease

The goal of the course is to guide students through the essential aspects of molecular neuroscience and neurodegenerative diseases. The student will gain the ability to dissect the molecular basis of disease in the nervous system in order to begin to understand and identify therapeutic strategies.