Search results for "Ophthalmology"

Ultrastructural study of the retina in late infantile metachromatic leukodystrophy.

1992

The autopsy of a 2-year-old girl revealed a clinically unrecognized metachromatic leukodystrophy (MLD) due to an aryl-sulfatase A deficiency, characteristically affecting the central and peripheral nervous system by demyelination and by accumulation of metachromatic material. The retina though reported clinically as normal, showed the same demyelinating process in the optic nerve including the papilla but an additional intraneuronal storage of MLD-typical lysosomal residual bodies in ganglion cell perikarya of the retina. Cells of the bipolar and photoreceptor layers as well as pigment epithelial cells were not affected by MLD-specific lysosomal storage. Thus, sulfatides seem to play a part…

Enrichment of Retinal Ganglion Cells in Rat Retinal Lysate by Excimer Laser Ablation of the Outer Retina

2013

PURPOSE. Retinal ganglion cells (RGC) are a relatively small cell population in the retina. This leads to an unfavorable signal-tonoise ratio when analyzing RGC proteins in whole retina lysate. We present a novel technique to obtain RGC-enriched rat retinal lysate by removing the outer retinal layers with an excimer laser before lysation. METHODS. Outer retinal layers were ablated with an excimer laser on flat mounted retinas from adult albino rats. 4 0 6Diamidino-2-phenylindole dihydrochloride hydrate (DAPI) nuclear staining was used to assess the ablation efficacy (n ! 6). Western blot for layer specific markers (rhodopsin, parvalbumin, b-III-tubulin) was performed to quantify changes in …

Short-Time Ocular Ischemia Induces Vascular Endothelial Dysfunction and Ganglion Cell Loss in the Pig Retina

2019

Visual impairment and blindness are often caused by retinal ischemia-reperfusion (I/R) injury. We aimed to characterize a new model of I/R in pigs, in which the intraocular pathways were not manipulated by invasive methods on the ocular system. After 12 min of ischemia followed by 20 h of reperfusion, reactivity of retinal arterioles was measured in vitro by video microscopy. Dihydroethidium (DHE) staining, qPCR, immunohistochemistry, quantification of neurons in the retinal ganglion cell layer, and histological examination was performed. Retinal arterioles of I/R-treated pigs displayed marked attenuation in response to the endothelium-dependent vasodilator, bradykinin, compared to sham-tre…

Role of nitric oxide synthase isoforms for ophthalmic artery reactivity in mice.

2014

Abstract Nitric oxide synthases (NOS) are involved in regulation of ocular vascular tone and blood flow. While endothelial NOS (eNOS) has recently been shown to mediate endothelium-dependent vasodilation in mouse retinal arterioles, the contribution of individual NOS isoforms to vascular responses is unknown in the retrobulbar vasculature. Moreover, it is unknown whether the lack of a single NOS isoform affects neuron survival in the retina. Thus, the goal of the present study was to examine the hypothesis that the lack of individual nitric oxide synthase (NOS) isoforms affects the reactivity of mouse ophthalmic arteries and neuron density in the retinal ganglion cell (RGC) layer. Mice defi…

Magnetic resonance imaging and optical coherence tomography correlations in multiple sclerosis beyond anatomical landmarks.

2020

Abstract Objective To investigate multiple sclerosis (MS) optical coherence tomography (OCT) cross-sectional correlations with central nervous system (CNS) magnetic resonance imaging (MRI). Material and methods Peripapillary retinal nerve fiber layer (pRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner (INL) and outer nuclear layer (ONL) of 54 relapsing remitting (RRMS) and 38 progressive (PMS, 9 primary and 29 secondary) patients were measured. With less than 3 months brain parenchymal fraction (BPF), spinal cord (SC), total gray matter (GM) and white matter volumes were calculated. Demographical and clinical data was compared according to the history of optic neuritis (H…

2017

Background Patients with retinal vascular occlusion disease have an increased risk for ischemic stroke and share some risk factors with cerebrovascular disease. The purpose of this study was to analyze the prevalence of atrial fibrillation (AF) in subjects with retinal vascular occlusive disease and anterior ischemic optic neuropathy and to compare these data to an ischemic stroke group. Methods Prospective, observational single-center trial. Subjects with retinal artery occlusion (RAO), retinal vein occlusion (RVO) and anterior ischemic optic neuropathy (AION) were included. Patients with ischemic stroke (IS) from a previous observational trial were used as control. Investigation included …

Influence of ocular aberrations on the diameter of retinal blood vessels

2011

Lower-order and higher-order ocular aberrations influence not only visual perception but also appearance of retinal images. We suggest that the diameter of blood vessels may differ for various patterns of aberrations based on how the maps of point spread functions are orientated to these vessels. We tested our hypothesis by a star chart simulation method and by using simulating aberrations in a real image of a living retina. We observed that broadening of the blood vessels due to ocular aberrations depends not only on the relative orientation of the wavefront but also on their actual width. The change in the diameter ratio is clinically significant and is comparable to changes in the arteri…

2013

Background To monitor viability of implanted genetically engineered and microencapsulated human stem cells (MicroBeads) in the mouse eye, and to study the impact of the beads and/or xenogenic cells on retinal integrity. Methodology/Principal Findings MicroBeads were implanted into the subretinal space of SV126 wild type mice using an ab externo approach. Viability of microencapsulated cells was monitored by noninvasive retinal imaging (Spectralis™ HRA+OCT). Retinal integrity was also assessed with retinal imaging and upon the end of the study by light and electron microscopy. The implanted GFP-marked cells encapsulated in subretinal MicroBeads remained viable over a period of up to 4 months…

A novel automated segmentation method for retinal layers in OCT images proves retinal degeneration after optic neuritis.

2015

Aim The evaluation of inner retinal layer thickness can serve as a direct biomarker for monitoring the course of inflammatory diseases of the central nervous system such as multiple sclerosis (MS). Using optical coherence tomography (OCT), thinning of the retinal nerve fibre layer and changes in deeper retinal layers have been observed in patients with MS. Here, we first compare a novel method for automated segmentation of OCT images with manual segmentation using two cohorts of patients with MS. Using this method, we also aimed to reproduce previous findings showing retinal degeneration following optic neuritis (ON) in MS. Methods Based on a 5×5 expansion of the Prewitt operator to efficie…

Dynamics, alterations, and consequences of minimally invasive intraocular pressure elevation in rats.

2014

PURPOSE: An important, yet not exclusive, aspect of primary open angle glaucoma is elevated intraocular pressure (IOP) profiles within fluctuations and pressure peaks. The study aimed at establishing minimally invasive methods for recurrent IOP elevation in rats to investigate the impact of IOP dynamics and pathomorphologic retinal alterations during and after IOP elevation. METHODS: Intraocular pressure was elevated unilaterally in Long Evans rats to a level of ≈35 mm Hg for 1 hour in a total of 30 manipulations within 6 weeks, by using two methods: (1) suction-cup oculopression and (2) loop-adjusted oculopression. Retinal thickness (RT) was measured via optical coherence tomography (OCT),…