Search results for "Ophthalmology"

Depth-of-Field of the Accommodating Eye

2014

Our eyes project information from a three-dimensional world to a basically two-dimensional surface, corresponding to the photoreceptor plane in the retina. In theory, only one plane or surface of world can be in focus at one time. However, the eye exhibits a certain tolerance to out-of-focus images, a feature that is known as depth-of-focus (DOF). The corresponding distance range in which the objects are seen “clearly” is known as depth-of-field (DOFi). Although DOF and DOFi refer to an interval of distances or a dioptric range in the image and object space, respectively, both parameters define a similar concept and are usually interchangeable. This article will mainly refer to DOFi because…

Evaluation of the iridocorneal angle with accommodation using optical coherence tomography

2017

The changes in the iridocorneal angle structure during accommodation are assessed by means of anterior segment optical coherence tomography. Thirteen right eyes were included in the study. The device used for the measurement was the Visante® omni system. The stimuli were set up at different vergences (0.0 D, -1.5 D, and -3.0 D). The angle opening distance 500 and 750, the trabecular iris space area 500 and 750, and the scleral spur angle parameters were assessed at the nasal and temporal regions. The results in the iridotrabecular angle comparing the three accommodative states of the eye did not yield any statistically significant difference at nasal or temporal angle sections. In light of …

Glaucoma and Antioxidants: Review and Update

2020

Glaucoma is a neurodegenerative disease characterised by the progressive degeneration of retinal ganglion cells. Oxidative stress has been related to the cell death in this disease. Theoretically, this deleterious consequence can be reduced by antioxidants substances. The aim of this review is to assemble the studies published in relation to antioxidant supplementation and its effects on glaucoma and to offer the reader an update on this field. With this purpose, we have included studies in animal models of glaucoma and clinical trials. Although there are variable results, supplementation with antioxidants in glaucoma may be a promising therapy in glaucoma.

Algorithms for the Automated Analysis of Age-Related Macular Degeneration Biomarkers on Optical Coherence Tomography: A Systematic Review

2017

PURPOSE To assess the quality of optical coherence tomography (OCT) grading algorithms for retinal biomarkers of age-related macular degeneration (AMD). METHODS Following a systematic review of the literature data on detection and quantification of AMD retinal biomarkers by available algorithms were extracted and descriptively synthesized. Algorithm quality was assessed using a modified version of the Quality Assessment of Diagnostic Accuracy Studies 2 checklist with a focus on accuracy against established reference standards and risk of bias. RESULTS Thirty five studies reporting computer-aided diagnosis (CAD) tools for qualitative analysis or algorithms for quantitative analysis were iden…

Fuch's heterochromic cyclitis and HLA histocompatibility antigens

1994

Genetic typing of class I major histocompatibility complex (MHC) antigens (HLA-A, -B and -C) was performed in 22 patients with Fuch's heterochromic cyclitis (FHC) and in a control group of 339 healthy subjects in order to ascertain whether there are any genetic factors that protect against or increase the risk of developing this disease. The frequency of only one HLA-antigen was found to differ significantly in the patients with FHC as compared with the normal subjects: HLA-A2 had a negative association with FHC (9.09% in FHC versus 47.47% in the control group; p<0.01, Fisher's exact test with correction for the number of antigens studied) with an odds ratio of 0.11 (95% confidence limits 0…

Predicting perceptual distortion sensitivity with gain control models of LGN

2017

Does autoimmunity play a part in the pathogenesis of glaucoma?

2013

Glaucoma is a chronic neurodegenerative disease and one of the leading causes of blindness. Several risk factors have been described, e.g. an elevated intraocular pressure (IOP), oxidative stress or mitochondrial dysfunction. Additionally, alterations in serum antibody profiles of glaucoma patients, upregulation (e.g. anti-HSP60, anti-MBP) and downregulation (e.g. anti-14-3-3), have been described, but it still remains elusive if the autoantibodies seen in glaucoma are an epiphenomenon or causative. However, it is known that elicited autoimmunity causes retinal ganglion cell loss resulting in glaucomatous-like damage and according to the autoaggressive nature of some autoantibodies we found…

Neuroprotection and autoimmunity in glaucoma

2012

In glaucoma, the elevated intraocular pressure cannot explain the disease in all patients. However, the pathogenesis of the disease is widely unknown. Biomarker research could be help to understand the disease process. Beside some genetic and proteomic biomarkers, immunoproteomics could play a significant role. Several studies could provide hints for an involvement of autoantibodies in the pathogenesis of the disease. The complex profiles of natural occurring autoantibodies were analyzed by Western Blotting and mass spectrometry based techniques combined with multivariate statistics and artificial neural networks. In several studies we could demonstrate consistent up- and down-regulations o…

Simultaneous Color Contrast in Goldfish— a Quantitative Study

1997

AbstractA set of 9–15 colored test fields was presented to goldfish. In Experiment 1, test field hues ranged from green through yellow to red; in Experiment 2, the hues varied from blue through gray to yellow. In the training conditions, the test fields were presented with a gray or black surround. The fish learned to choose one intermediate test field hue by rewarding them with food. In the test conditions, the color of the surround was changed from gray to green, or red (Experiment 1), and from black to blue, or yellow (Experiment 2). The choice behavior of the goldfish changed substantially: one of the test fields other than the training test field was preferred. Direction and strength o…

Tear &lt;sup&gt;1&lt;/sup&gt;H Nuclear Magnetic Resonance-Based Metabolomics Application to the Molecular Diagnosis of Aqueous Tear Deficiency and Me…

2020

&lt;b&gt;&lt;i&gt;Purpose:&lt;/i&gt;&lt;/b&gt; Meibomian gland dysfunction (MGD) is a major cause of signs and symptoms related to dry eyes (DE) and eyelid inflammation. We investigated the composition of human tears by metabolomic approaches in patients with aqueous tear deficiency and MGD. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; Participants in this prospective, case-control pilot study were split into patients with aqueous tear deficiency and MGD (DE-MGD [&lt;i&gt;n&lt;/i&gt; = 15]) and healthy controls (CG; &lt;i&gt;n&lt;/i&gt; = 20). Personal interviews, ocular surface disease index (OSDI), and ophthalmic examinations were performed. Reflex tears collected by capillarity were pr…