Search results for "Optometry"
showing 10 items of 812 documents
Normal values for fundus perimetry with the MAIA microperimeter and short-term repeatability evaluation
2016
National audience; Purpose To assess retinal sensitivity by means of microperimetry and to evaluate the intersession fluctuation using the MAIA microperimeter in healthy volunteers. Methods Prospective, monocentre study. Fifty‐six healthy volunteers (age range, 20–80 years), underwent an automatic, full‐threshold microperimetry of the central field (custom grid, area of 10° in diameter, 37 stimulated points), with the MAIA microperimeter (CenterVue, Padova, Italy). A subgroup of 24 subjects was retested after 1 h (test 2) and 1 week (test 3) to determine the repeatability of the technique. A subgroup of 22 subjects was also tested on the OPKO microperimeter (Optos, Dunfermline, Scotland) (a…
Repeatability of in-vitro optical quality measurements of intraocular lenses with a deflectometry technique effect of the toricity
2018
Aim To evaluate the repeatability of an optical device for measuring the Zernike coefficients of toric intraocular lenses (IOLs) and assess whether its toricity has any impact in its repeatability. Methods An experienced technician used the NIMO TR1504 to measure the Zernike coefficients 30 times for an aperture of 4.50 mm for all lenses included. The IOLs included were divided into two group: toric and non-toric ones. The cylindrical powers of the toric lenses included in the present study were 1.00, 1.50, 2.25, 3.00 and 3.75 D. Finally, the repeatability of the NIMO TR1504 was described in terms of within subject standard deviation (Sw) and repeatability limit. Results The Sw was smaller …
Cholestérol et pathologies oculaires : focus sur le rôle de la cholestérol 24S-hydroxylase (CYP46A1) dans l’homéostasie du cholestérol
2015
Resume La retine est le tissu neurosensoriel de l’œil qui assure la transduction visuelle, c’est-a-dire le codage de l’information lumineuse en influx nerveux. Le terme « retine » regroupe l’association de la retine neurale et de l’epithelium pigmentaire retinien qui repose sur la membrane de Bruch. L’association physique de ces deux partenaires et leurs interactions metaboliques sont des elements indispensables au bon fonctionnement de la retine, a la fois en termes d’apport en nutriments et de maintien de l’homeostasie. Des dereglements de ces equilibres sont associes au vieillissement et a des pathologies comme la degenerescence maculaire liee a l’âge, premiere cause de malvoyance apres …
Face masks considerably reduce COVID-19 cases in Germany
2020
Significance Mitigating the spread of COVID-19 is the objective of most governments. It is of utmost importance to understand how effective various public health measures are. We study the effectiveness of face masks. We employ public regional data about reported severe acute respiratory syndrome coronavirus 2 infections for Germany. As face masks became mandatory at different points in time across German regions, we can compare the rise in infections in regions with masks and regions without masks. Weighing various estimates, we conclude that 20 d after becoming mandatory face masks have reduced the number of new infections by around 45%. As economic costs are close to zero compared to oth…
Widening use of dexamethasone implant for the treatment of macular edema
2017
Vincenza Bonfiglio, Michele Reibaldi, Matteo Fallico, Andrea Russo, Alessandra Pizzo, Stefano Fichera, Carlo Rapisarda, Iacopo Macchi, Teresio Avitabile, Antonio Longo Department of Ophthalmology, University of Catania, Catania, Italy Abstract: Sustained-release intravitreal 0.7 mg dexamethasone (DEX) implant is approved in Europe for the treatment of macular edema related to diabetic retinopathy, branch retinal vein occlusion, central retinal vein occlusion, and non-infectious uveitis. The implant is formulated in a biodegradable copolymer to release the active ingredient within the vitreous chamber for up to 6 months after an intravitreal injection, allowing a prolonged interval of effica…
Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and me…
2017
PubMed: 28779882
Accommodative Stimulus-Response Curve with Emoji Symbols
2017
Purpose. To evaluate the static measurement of the accommodative stimulus-response curve with emoji symbols. Methods. The accommodative stimulus-response curve was measured in 18 subjects using a Hartmann-Shack sensor to obtain the objective accommodative response from the Zernike defocus term. Measurements were acquired at different accommodative demands, from 0 to 3 D with a step of 0.5 D. Detailed and nondetailed emoji targets were used with two different sizes, corresponding to the two most common visual angles used in smartphones. Results. A regression analysis was performed to fit the mean results obtained for each target. The determination coefficient was R2≥0.988 for all targets. Fo…
Accommodative response in various design soft contact lens wearers
2021
The progression of myopia in young adults due to inadequate accommodation is currently one of the global research challenges. Studies have demonstrated that multifocal contact lenses have a different effect on accommodative response. The aim of this study was to assess the accommodative lag using various design multifocal contact lenses at different working distances. The study was conducted on 10 emmetropic subjects aged 22â28 years. An open-field autorefractor PowerRef 3 was used to assess the response of eye accommodation to stimuli placed at a distance of 25 cm and 40 cm for subjects wearing monofocal and multifocal contact lenses. To determine the effectiveness of contact lens design f…
Objective Amplitude of Accommodation Computed from Optical Quality Metrics Applied to Wavefront Outcomes
2009
Purpose: We studied the accuracy and precision of 32 objective wavefront methods for finding the amplitude of accommodation obtained in 180 eyes. Methods: Ocular accommodation was stimulated with 0.5 D steps in target vergence spanning the full range of accommodation for each subject. Subjective monocular amplitude of accommodation was measured using two clinical methods, using negative lenses and with a custom Badal optometer. Results: Both subjective methods gave similar results. Results obtained from the Badal optometer where used to test the accuracy of the objective methods. All objective methods showed lower amplitude of accommodation that the subjective ones by an amount that varied …
Oxidative Stress and Microvascular Alterations in Diabetic Retinopathy: Future Therapies
2019
Diabetes is a disease that can be treated with oral antidiabetic agents and/or insulin. However, patients’ metabolic control is inadequate in a high percentage of them and a major cause of chronic diseases like diabetic retinopathy. Approximately 15% of patients have some degree of diabetic retinopathy when diabetes is first diagnosed, and most will have developed this microvascular complication after 20 years. Early diagnosis of the disease is the best tool to prevent or delay vision loss and reduce the involved costs. However, diabetic retinopathy is an asymptomatic disease and its development to advanced stages reduces the effectiveness of treatments. Today, the recommended treatment for…