929 resultados para Ophthalmology.


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Purpose. We quantified the main sequence of spontaneous blinks in normal subjects and Graves' disease patients with upper eyelid retraction using a nonlinear and two linear models, and examined the variability of the main sequence estimated with standard linear regression for 10-minute periods of time. Methods. A total of 20 normal subjects and 12 patients had their spontaneous blinking measured with the magnetic search coil technique when watching a video during one hour. The main sequence was estimated with a power-law function, and with standard and trough the origin linear regressions. Repeated measurements ANOVA was used to test the mean sequence stability of 10-minute bins measured with standard linear regression. Results. In 95% of the sample the correlation coefficients of the main sequence ranged from 0.60 to 0.94. Homoscedasticity of the peak velocity was not verified in 20% of the subjects and 25% of the patients. The power-law function provided the best main sequence fitting for subjects and patients. The mean sequence of 10-minute bins measured with standard linear regression did not differ from the one-hour period value. For the entire period of observation and the slope obtained by standard linear regression, the main sequence of the patients was reduced significantly compared to the normal subjects. Conclusions. Standard linear regression is a valid and stable approximation for estimating the main sequence of spontaneous blinking. However, the basic assumptions of the linear regression model should be examined on an individual basis. The maximum velocity of large blinks is slower in Graves' disease patients than in normal subjects. © 2013 The Association for Research in Vision and Ophthalmology, Inc.

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As occurs with a number of drugs, the bioavailability of amphotericin B (AmB) used to treat fungal infections by the ocular route remains a great challenge to research scientists. In fact, the poor bioavailability of AmB is due mainly to the corneal barrier, which leads to a precorneal loss and consequent decrease in the absorption of this drug into the intraocular tissues. The toxicity associated with this molecule, together with its poor ability to penetrate the intact corneal epithelium, also represents a major drawback to its clinical use. New effective and safe drug vehicles for ocular delivery of AmB are therefore urgently needed. Microemulsions (MEs) seem to be an interesting system, owing to their transparent appearance, thermodynamic stability and favorable viscosity. Knowledge of the process of formation of AmB-containing MEs, as well as a good understanding of the physical chemistry of such systems, would provide reliable information on the best conditions for the use of these systems as eye drops. The goal of this research was thus to make an approach to this subject by reviewing the main studies on the use of MEs as delivery systems for AmB in topical eye treatment.

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This work proposes a method for dioptric power mapping of progressive lenses through dual wavelength, low-coherence digital speckle pattern interferometry. Lens characterization finds several applications and is extremely useful in the fields of ophthalmology and astronomy, among others. The optical setup employs two red diode lasers which are conveniently aligned and tuned in order to generate a synthetic wavelength. The resulting speckle image formed onto a diffusive glass plate positioned behind the test lens appears covered of contour interference fringes describing the deformation on the light wavefront due to the analyzed lens. By employing phase stepping and phase unwrapping methods the wavefront phase was retrieved and then expressed in terms of a Zernike series. From this series, expressions for the dioptric power and astigmatic power were derived as a function of the x- and y-coordinates of the lens aperture. One spherical and two progressive lenses were measured. The experimental results presented a good agreement with those obtained through a commercial lensometer, showing the potentialities of the method. © 2013 Elsevier Ltd.

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Objective To describe the technique of deep anterior lamellar keratoplasty (DALK) with Descemet's membrane (DM) exposure in horse eyes. Also, to compare the efficacy and safety of viscodissection and big-bubble techniques for DALK. Animals studied Thirty-four ex vivo horse eyes. Procedure Deep anterior lamellar keratoplasty was performed in 34 ex vivo horse eyes. Two groups (Group V - viscodissection - 2% sodium hyaluronate; Group A - air - big-bubble) of 17 eyes were studied. Other than the substance used, the surgical technique was similar for both groups. Nonperforated eyes were submitted for light microscopic histologic evaluation and scanning electron microscopic (SEM) analysis. Results Group V - Perforations occurred in 18% of the eyes during surgery. Light microscopy revealed exposure of DM in 28% of the eyes with mean thickness of the remaining stroma being 70.4μm. Group A - Perforations occurred in 42% of the eyes. Light microscopy revealed exposure of DM in 60% of the eyes with mean thickness of the remaining stroma being 23.3μm. No significant differences in safety, efficacy and thickness of the remaining stroma (including all eyes or excluding those with DM exposure) were observed. SEM of the surgical site revealed a more even surface in those eyes with DM exposure compared to eyes with thicker remaining stroma in both groups. Conclusions We describe two DALK techniques (viscodissection and big-bubble) for use in horses. No significant differences in safety, efficacy and thickness of the remaining stroma were observed. However, a nonsignificant trend toward the big-bubble technique being more efficacious but less safe was observed. © 2012 American College of Veterinary Ophthalmologists.

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Glaucoma is a syndrome that affects animals of different species and in different moments of his life, having variables causes in function of this presentation. It is an ophthalmic emergency that may develop irreversible vision damage as well as the patient's aesthetic presentation. Increased intraocular pressure, presence of engorged episcleral vessels, conjunctival hyperemia, pain, anterior uveitis, lens luxation and buftalmia are commonly clinical signs presented by dogs while in cats, signs are less expressive, noting mydriasis, mild ciliary injection and progressive buftalmia. For diagnosis are carried out three basic procedures: tonometry, gonioscopy and ophthalmoscopy. The treatment can establish with medical therapy with or without surgical intervention, however, at some point it will be necessary to perform enucleation or evisceration of the eye bulb.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciência Animal - FMVA

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Pós-graduação em Medicina Veterinária - FMVZ

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Pós-graduação em Cirurgia Veterinária - FCAV