Search results for "Retinal"
showing 10 items of 631 documents
BARDET-BIEDL SYNDROME – CASE PRESENTATION
2015
Bardet-Biedl syndrome (autosomal-recessive inheritance) is characterized by obesity, retinal dystrophy, polydactyly and mental retardation. The authors emphasize the necessary steps in order to establish the diagnosis for an infant with overweight, polydactyly and hypo-genitalism.
Visual Health Nanocomposites: Present and Future
2021
Background: In recent years, the therapeutics for eye diseases as retinopathy diabetic, dry eye, glaucoma and contact lenses fabrication are including nanocompounds as ocular drug delivery systems, biomarkers for detection of eye diseases, copper and silver ions that has been incorporated by means of the nanotechnology for the production of less toxic and more effective alternatives. Several compounds such as silver nanoparticles, turmeric-based nanocomposites, neovascularization blockers and nanoparticles extracted from the plant Costus pictus among others have been researched for this purpose. Those compounds are some of the promising research efforts that are studying and will contribute…
Antibodies to alpha B-crystallin, vimentin, and heat shock protein 70 in aqueous humor of patients with normal tension glaucoma and IgG antibody patt…
2007
To show the existence of IgG antibodies against retinal antigens in aqueous humor of normal tension glaucoma patients.Forty-two patients were included in this study. Aqueous humor was collected from control subjects (CO; n = 21) and patients with normal tension glaucoma (NTG; n = 21). Western blot methods against bovine retinal antigens were used to detect the IgG antibody patterns. The complex antibody repertoires were analyzed by multivariate statistical techniques. Mass spectrometry was used to identify the most important antigens.Very complex IgG antibody patterns against retinal antigens were found in all analyzed aqueous humor samples. Our multivariate approach could quantify differen…
Color induction via non-opponent lateral interactions in the human retina
1992
Retinal connections causing colors in Benham's top (pattern induced flicker colors, PIFCs) are investigated by psychophysical experiments. PIFCs are still seen when stimuli to different cones are demodulated selectively, indicating the involvement of non-opponent channels. PIFCs also occur on retinal areas next to those affected by modulated stimuli; further, both monochromat and dark-adapted trichromats perceive PIFCs which are achromatic. These additional findings point to horizontal cells as neuronal mediators of modulated excitation leading to PIFCs. The unspecifity of the postulated connection with respect to cone types agrees with anatomic findings of Boycott, B. B., Hopkins, J. M. an…
Motion detection in goldfish investigated with the optomotor response is “color blind”
1996
AbstractThe action spectrum of the optomotor response in goldfish was measured to investigate which of the four cone types involved in color vision contributes to motion detection. In the dark-adapted state, the action spectrum showed a single maximum in the range of 500–520 nm, and resembled the rod spectral sensitivity function. Surprisingly, the action spectrum measured in the light-adapted state also revealed a single maximum only, located in the long wavelength range between 620 and 660 nm. A comparison with spectral sensitivity functions of the four cone types suggests that motion detection is dominated by the L-cone type. Using a two colored, “red-green” cylinder illuminated with two…
Visual fields in a chloroquine treatment
2014
Purpose: In this study, we describe contrast sensitivity losses in the visual field of a patient affected by chloroquine toxicity, measured with stimuli favoring different visual mechanisms. We have compared these results with those of other, usual clinical tests. Methods: The vision of a patient who underwent ten years of chloroquine treatment was analyzed by a battery of clinical tests: visual acuity (VA), Amsler’s grid, Farnsworth–Munsell 100-hue test, spectral domain optical coherence tomography, multifocal electroretinogram (ERG), white-on-white and red-on-white Humphrey perimetries, chromatic and achromatic contrast sensitivity perimetry tests, and fluorescein angiography. Measurement…
Schematic eye models to mimic the behavior of the accommodating human eye
2018
A simplified version of the human eye is known as schematic eye model. Since the first attempts in the middle of the 19th century, numerous approaches describing new schematic eye models have been introduced. Some of them are able to describe the accommodation ability of the human eye. Accommodative schematic eyes could be of great interest since they are able to explain the functionality of the human eye and they can be easily used for different research purposes. Some of these include the design and testing of multifocal ophthalmic solutions, evaluation of the effect of optical aberrations on the retinal image quality, and study of the optical performance of the eye at different distances…
Electrofunctional features of the tilted disc syndrome.
1986
The ERG, EOG and VEPs of 15 patients with tilted disc syndrome were studied. The ERG showed abnormal amplitudes in about 1/4 of the eyes and the EOG values were pathological in 3 patients. It is probable that the abnormality of the inferior-nasal portion of the retina and retinal pigment epithelium seen in the tilted disc syndrome causes the changes in the ERG and EOG. Pattern VEPs latency was delayed in most patients. This finding is probably due to the poor focusing of the light in the retina.
Pigment patterns in mutants affecting the biosynthesis of pteridines and xanthommatin in Drosophila melanogaster.
1986
Eye-color mutants of Drosophila melanogaster have been analyzed for their pigment content and related metabolites. Xanthommatin and dihydroxanthommatin (pigments causing brown eye color) were measured after selective extraction in acidified butanol. Pteridines (pigments causing red eye color) were quantitated after separation of 28 spots by thin-layer chromatography, most of which are pteridines and a few of which are fluorescent metabolites from the xanthommatin pathway. Pigment patterns have been studied in 45 loci. The pteridine pathway ramifies into two double branches giving rise to isoxanthopterin, “drosopterins,” and biopterin as final products. The regulatory relationship among the …
Interaction of glutamic-acid-rich proteins with the cGMP signalling pathway in rod photoreceptors.
1999
The assembly of signalling molecules into macromolecular complexes (transducisomes) provides specificity, sensitivity and speed in intracellular signalling pathways. Rod photoreceptors in the eye contain an unusual set of glutamic-acid-rich proteins (GARPs) of unknown function. GARPs exist as two soluble forms, GARP1 and GARP2, and as a large cytoplasmic domain (GARP' part) of the beta-subunit of the cyclic GMP-gated channel. Here we identify GARPs as multivalent proteins that interact with the key players of cGMP signalling, phosphodiesterase and guanylate cyclase, and with a retina-specific ATP-binding cassette transporter (ABCR), through four, short, repetitive sequences. In electron mic…