Search results for "AOC"

Evaluation of intraocular pressure and other biomechanical parameters to distinguish between subclinical keratoconus and healthy corneas

2021

(1) Purpose: To assess the main corneal response differences between normal and subclinical keratoconus (SCKC) with a Corvis® ST device. (2) Material and Methods: We selected 183 eyes of normal patients, of a mean age of 33 ± 9 years and 16 eyes of patients with SCKC of a similar mean age. We measured best corrected visual acuity (BCVA) and corneal topography with a Pentacam HD device to select the SCKC group. Biomechanical measurements were performed using the Corvis® ST device. We carried out a non-parametric analysis of the data with SPSS software (Wilcoxon signed rank-test). (3) Results: We found statistically significant differences between the control and SCKC groups in some corneal b…

Lentes intraoculares multifocales refractivas de nuevo diseño segmentado

2017

La presbicia y las cataratas son dos condiciones oculares relacionadas con el envejecimiento del cristalino, que presentan una elevada incidencia conjunta por encima de los 60 años. Dada la tendencia, claramente visible en los estudios de pirámides poblacionales, al envejecimiento en la población mundial por la mayor esperanza de vida, ambas condiciones van a tener una enorme incidencia en el futuro. Ambas comparten una opción terapéutica común: la sustitución del cristalino por una lente intraocular multifocal (LIOMTF), que permite a los pacientes restaurar su visión y además obtener un amplio rango de distancias con visión funcional sin necesidad de ayudas ópticas. En la actualidad existe…

Efficacy and safety study of an eyelid gel after repeated nocturnal application in healthy contact lens users and non-users

2020

Purpose: To evaluate skin biocompatibility of a nighttime hydrating eyelid gel and possible ocular surface effects in contact lens users (CLU) and non-contact lens users (NCLU). The formulation is registered as a medical device as Tridocosahexaenoine-AOX® (TDHA-AOX) (a concentrated DHA triglyceride), containing also hyaluronic acid (HA). Methods: A prospective, randomized, masked clinical trial was performed with 62 participants of both sexes, aged 20–70 years, split into: (1) CLU (n = 30) and (2) NCLU (n = 32). All participants were instructed to apply a single dose of the moisturizing gel (containing TDHA-AOX and HA) nightly to the upper and inner eyelids of their right eye (RE) only, and…

Morphology of Skeletal Muscle

2013

Skeletal muscle makes up the largest organ of the body, by both volume and weight, comprising more than 40 %. More than 500 diseases concern muscle tissue, the majority of which originate in muscle, others secondarily affect the muscle, foremost by denervation. The functional and structural dependence of skeletal muscle on innervation—that is, the peripheral and central nervous systems—renders muscle tissue unique and adds a dimension to the nosology, more obviously than in other organs. Therefore, diseases affecting muscle are also termed neuromuscular diseases. Within the nosological spectrum of the muscle parenchyma, which encompasses hereditary and acquired conditions, muscular dystroph…

Management of Descemet's membrane haemorrhage after canaloplasty

2019

Agreement among 3 optical imaging methods for the assessment of optic disc topography.

2005

Purpose To assess the agreement of disc topography measurements between the Heidelberg Retina Tomograph (HRT II), Retinal Thickness Analyzer (RTA), and Optical Coherence Tomograph (StratusOCT). Design Observational cross-sectional study. Participants Forty-two randomly chosen eyes of 42 subjects. Methods Each subject underwent HRT II, RTA, and StratusOCT examination. Two experienced examiners drew the contour lines for the HRT II and RTA. Bland and Altman plots were used to evaluate agreement for each topographic parameter among the instruments. The Spearman coefficient of rank correlation was evaluated for each topographic parameter. Main Outcome Measures Agreement in the measurement of op…

Proposal of a new diffractive corneal inlay to improve near vision in a presbyopic eye

2020

[EN] A new class of diffraction-based corneal inlays for treatment of presbyopia is described. The inlay is intended to achieve an improvement of the near focus quality over previous designs. Our proposal is a two-zone hybrid device with separated amplitude and phase areas having a central aperture and no refractive power. An array of micro-holes is distributed on the surface of the inlay conforming a binary photon sieve. In this way, the central hole of the disk contributes to the zero order of diffraction, and the light diffracted by the micro-holes in the peripheral photon sieve produces a real focus for near vision. We employed ray-tracing software to study the performance of the new in…

Fractal-structured multifocal intraocular lens

2017

[EN] In this work, we present a new concept of IOL design inspired by the demonstrated properties of reduced chromatic aberration and extended depth of focus of Fractal zone plates. A detailed description of a proof of concept IOL is provided. The result was numerically characterized, and fabricated by lathe turning. The prototype was tested in vitro using dedicated optical system and software. The theoretical Point Spread Function along the optical axis, computed for several wavelengths, showed that for each wavelength, the IOL produces two main foci surrounded by numerous secondary foci that partially overlap each other for different wavelengths. The result is that both, the near focus an…

Ophthalmic: Laboratorio virtual para el diseño de nuevas lentes oftálmicas

2013

This work presents a new virtual laboratory, OPHTALMIC, developed with MATLAB GUI for using in Optics and Optometry courses as a computer tool for studying the focusing properties of multifocal diffractive both on unconventional structures both periodic and aperiodic. This virtual laboratory enables students to quickly and easily analyze the influence of the different parameters of construction and find the best solution for a user.

Material properties of various intraocular lenses in an experimental study.

2002

<i>Introduction:</i> With the recent introduction of small-incision cataract surgery, requirements for intraocular lens (IOL) flexibility, strength and hydrophilicity have rapidly evolved. The IOL surface, however, remains a critical factor influencing uveal biocompatibility. <i>Purpose:</i> To objectively quantify factors of material properties of various IOLs using contact angle measurements, differential scanning calorimetry, dynamic-mechanical measurements and scanning electron microscopy. <i>Material and Methods:</i> In our study, 17 currently available IOLs were investigated using contact angle measurements to assess hydrophilicity and biocompatibil…