Search results for "Eye"
showing 10 items of 2511 documents
The role of neuroinflammation in the pathogenesis of glaucoma neurodegeneration
2020
The chapter is a review enclosed in the volume "Glaucoma: A pancitopatia of the retina and beyond." No cure exists for glaucoma. Knowledge on the molecular and cellular alterations underlying glaucoma neurodegeneration (GL-ND) includes innovative and path-breaking research on neuroinflammation and neuroprotection. A series of events involving immune response (IR), oxidative stress and gene expression are occurring during the glaucoma course. Uveitic glaucoma (UG) is a prevalent acute/chronic complication, in the setting of chronic anterior chamber inflammation. Managing the disease requires a team approach to guarantee better results for eyes and vision. Advances in biomedicine/biotechnolog…
<title>Modified crossed-cylinder aberroscope</title>
2001
We report a technique to estimate eye aberrations, based mainly on the subjective crossed-cylinder method. In order to obtain accurate coordinates of cross sections of the aberration distorted grid image on the retinal plane, needed in subjective methods, fusion of two images is used. The image seen by the eye under investigation is fused by the patient with a similar grid generated and reshaped in the appropriate way on the computer screen. The computer simulated image is viewed either by the second eye (in order to avoid eye rivalry and suppression processes, that are typical for such conditions, stimuli for both eyes are discontinuous and are displayed sequentially with a frequency of 50…
Anatomy of the visual system
2004
This brief systemic overview presents the anatomic details of the orbit with respect to imaging modalities CT and MR. The structures of the four orbital compartments, intrakonal and extrakonal space, globe and optic nerve are demonstrated in detail on different CT and MR views (axial, coronal, in soft tissue and bone window, T1-weighted, T2-weighted) with corresponding diagrams. The intracranial visual pathway is explained in detail with emphasis to the striate cortex and extrastriate visual association cortex, presented with diagrams and high-resolution MR.
Simple Configuration Effects on Eye Movements in Horizontal Scanning Tasks
2015
When reading text, observers alternate periods of stable gaze (fixations) and shifts of gaze (saccades). An important debate in the literature concerns the processes that drive the control of these eye movements. Past studies using strings of letters rather than meaningful text ('z-reading') suggest that eye movement control during reading is, to a large extent, controlled by low-level image properties. These studies, however, have failed to take into account perceptual grouping processes that could drive these low-level effects. We here study the role of various grouping factors in horizontal scanning eye movements, and compare these to reading meaningful text. The results show that sequen…
VisuMax®femtosecond laser for corneal refractive surgery
2008
Femtosecond lasers are increasingly present in ophthalmologic surgical theaters for a variety of reasons. These include faster and better visual outcomes, increased accuracy and predictability for corneal flap thickness in laser in situ keratomileusis procedures. Recent applications of modern femtosecond lasers have broadened the range of uses: keratoplasty, intrastromal segment insertion and even glaucoma and presbyopia surgery. This device profile provides an overview of the advantages of femtosecond lasers in ophthalmic surgery, paying special attention to the new VisuMax® femtosecond laser from Zeiss/Meditec.
Beals–Hecht syndrome and choroidal neovascularization
2010
Purpose: To describe a case of choroidal neovascularization (CNV) in a female diagnosed with Beals–Hecht syndrome. Methods: A retrospective, interventional case is described in a 26-year-old female complaining of metamorphopsia and visual loss in her left eye (counting fingers). The fluorescein angiogram and the optical coherence tomography supported the diagnosis of CNV. Intravitreal ranibizumab was administered. Results: After the third intravitreal ranibizumab, her visual acuity improved to 0.8 and the morphology of the macular area was restored. Conclusions: To our knowledge this is the first report of CNV in Beals–Hecht syndrome treated with ranibizumab. Self-monitoring by periodically…
Nuevos factores de riesgo para la progresión del Glaucoma
2015
INTRODUCCIÓN El Glaucoma es una neuropatía óptica de desarrollo progresivo que afecta a 90 millones de habitantes del planeta, siendo la forma clínica conocida como glaucoma primario de ángulo abierto (GPAA) la primera causa de ceguera irreversible en los países desarrollados. Los factores de riesgo para su desarrollo incluyen en primer lugar la presión intraocular, pero también la edad, la raza, la predisposición familiar, el espesor corneal central, miopía y presión de perfusión ocular han sido descritos como importantes en el desarrollo y/o progresión del glaucoma, entre otros. No obstante, hay evidencia acerca de la existencia de otros factores de riesgo, los denominados emergentes, así…
Prevalence and risk factors for myopia and other refractive errors in an adult population in southern India.
2018
PURPOSE: To investigate prevalence and risk factors for myopia, hyperopia and astigmatism in southern India. METHODS: Randomly sampled villages were enumerated to identify people aged ≥40 years. Participants were interviewed for socioeconomic and lifestyle factors and attended a hospital-based ophthalmic examination including visual acuity measurement and objective and subjective measurement of refractive status. Myopia was defined as spherical equivalent (SE) worse than -0.75 dioptres (D), hyperopia as SE ≥+1D and astigmatism as cylinder <-0.5. RESULTS: The age-standardised prevalences of myopia, hyperopia and astigmatism were 35.6% (95% CI: 34.7-36.6), 17.0% (95% CI: 16.3-17.8) and 32.6 (…
Artificial pupil versus contralateral balanced contact lens fit for presbyopia correction
2018
Purpose: To assess and compare the effects of contact lens-based artificial pupil design and contralateral balanced multifocal contact lens combination (CBMCLC) on visual performance. Methods: This randomized crossover study conducted at the University of Valencia, Spain included 38 presbyopic patients using an artificial pupil contact lens in the nondominant eye and a CBMCLC. After a month of lens wear, the binocular distance visual acuity (BDVA), binocular near visual acuity (BNVA), defocus curve, binocular distance, and near contrast sensitivity and near stereoacuity (NSA) were measured under photopic conditions (85 cd/m2). Moreover, BDVA and binocular distance contrast sensitivity were …
In vivo consequences of cholesterol-24s-hydroxylase (CYP46A1) inhibition by voriconazole on cholesterol homeostasis and function in the rat retina
2011
Cholesterol 24S-hydroxylase (CYP46A1) converts cholesterol into 24S-hydroxycholesterol in neurons and participates in cholesterol homeostasis in the central nervous system, including the retina. We aimed to evaluate the consequences of CYP46A1 inhibition by voriconazole on cholesterol homeostasis and function in the retina. Rats received daily intraperitoneal injections of voriconazole (60mg/kg), minocycline (22mg/kg), voriconazole plus minocycline, or vehicle during five consecutive days. The rats were submitted to electroretinography to monitor retinal functionality. Cholesterol and 24S-hydroxycholesterol were measured in plasma, brain and retina by gas chromatography-mass spectrometry. T…