Verre correcteur

Résumé

Un verre correcteur est une lentille optique portée devant l'œil, principalement pour corriger les amétropies : myopie, hypermétropie, astigmatisme et presbytie. Les lunettes sont portées à une faible distance des yeux. Les lentilles de contact sont portées directement à la surface de l'œil. Les lentilles intraoculaires sont implantées chirurgicalement, majoritairement pour corriger la cataracte. La myopie est corrigée par une lentille divergente, l'hypermétropie par une lentille convergente, l'astigmatisme par une lentille torique (qui peut être divergente, convergente ou les deux), et la presbytie par une lentille progressive (dont la correction varie). Prescription des verres correcteurs Les verres correcteurs sont prescrits, en France, par un ophtalmologue. Dans divers pays les opticiens ou les optométristes peuvent prescrire les verres correcteurs. L'ordonnance contient les principaux paramètres de correction : puissance pour chaque œil pour la vision de loin (ou de

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https://fr.wikipedia.org/wiki/Verre_correcteur

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First steps toward noninvasive intraocular pressure monitoring with a sensing contact lens

Daniel Bertrand, Arnaud Bertsch, Matteo Leonardi, Philippe Renaud

PURPOSE. To present a novel and minimally invasive approach to intraocular pressure (IOP) monitoring based on a sensing contact lens. METHODS. The key element of this measurement method is a soft contact lens with an embedded microfabricated strain gauge allowing the measurement of changes in corneal curvature correlated to variations in IOP. A prototype of this sensing contact lens was adapted and tested on enucleated porcine eyes. To verify the measurement principle of the device, the posterior chamber of the pig eyes was cannulated and connected to a syringe pump and a pressure sensor for precise control of IOP. The measurements of the contact lens were then compared to the ones from the pressure sensor, while pressure variations were induced through the cannula. RESULTS. Enucleated porcine eyes were stimulated with increasing and decreasing ramps of IOP. Measurements from the sensing contact lens and from the pressure sensor showed very good correlation, proving the high potential of this new measurement principle. In this study, a typical signal from the sensing contact lens obtained during the experiments is presented and discussed. CONCLUSIONS. The sensing contact lens shows the potential for continuously monitoring IOP in enucleated porcine eyes. The ultimate step will be the validation of the system and the reproducibility of results in humans. The device is placed in the same way as a corrective contact lens, no anesthesia is required, and vision remains almost unimpaired. This device would allow minimally invasive IOP monitoring over prolonged periods, regardless of the patient's position and activity, thus opening up new diagnostic and therapeutic methods for the management of glaucoma.

2004

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Multiple-Field Approach for Aberration Correction in Miniature Imaging Systems Based on Wafer-Level Production

Nicolas Bongard, Hans Peter Herzig, Toralf Scharf

IIn mobile imaging systems, the most difficult element to integrate is the objective lens. Here we present an intermediate approach between the costly traditional objectives and the low-resolution objectives inspired by the compound eyes of insects. Our multi-field approach uses a small number of optical channels each imaging a portion of the desired field of view. The full-field image is reconstructed digitally. The optics of each channel is kept simple for wafer-level fabrication and its size is sufficient to obtain a reasonable resolution. We present the design and fabrication of a prototype using 9 plano-convex lenses for 9 channels. Glass lenses glued on a wafer are used to image a full-field of ±40° with an f-number of 3. The images obtained shows field curvature correction. A simple image reconstruction scheme is presented. In conclusion, multi-field objectives fabricated with micro-optics technology are thin, simple to mount, robust, and easily replicated

SPIE Digital Library2013

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Tolerancing is an important step toward the fabrication of high-quality and cost-effective lens surfaces. It is critical for wafer-level optics, when up to tens of thousands microlenses are fabricated in parallel and whose surfaces cannot be formed individually. However, approaches developed for macro-optics cannot be directly transposed for microlenses because of differences in fabrication and testing techniques. In particular, microlens surfaces are usually limited to conical surfaces. Here, we study the connection between the microlens optical performance and the form of its surface, suggesting surface form representations suited for tolerancing purposes. Then, we compare them with common representations for tolerancing real optical systems. Measured surface forms of microlenses are also provided to make the tolerancing procedure realistic. In addition, we propose term definitions for microoptics, complements to typical terms for macro-optics, to ease the communication between optical designers and manufacturers. Based on the results presented in this paper, guidelines are proposed for tolerancing microlenses. We suggest applying them as a first step toward a more effective and comprehensive tolerancing procedure. (C) 2020 Optical Society of America

OPTICAL SOC AMER2020

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