Home About us Contact
|
Home About us Contact | ||
|
|
||
Optic Nerve Head (optic + nerve_head)
Selected AbstractsPreterm and at term children: morphological and functional analysis of optic nerve and visual pathway with OCT, HRT and pVEPACTA OPHTHALMOLOGICA, Issue 2009R ANGELI Purpose To compare optic nerve morphology and visual function in 14 preterm children(mean gestational age:33,38) with normal cerebral ultrasound at birth and 15 at term children (mean gestational age:39,67). Methods Mean preterm age was 7,6 years, mean at term was 9,1 years. Children underwent to complete functional and morphological evaluation of Optic Nerve Head (ONH) with Heidelberg Retinal Tomography and Optical Coherence Tomography. The same children were evaluated at birth and at the time of morphological examinations by mean of transient and steady state pVEP. Results Mean visual acuity was 9,85 in the preterm, 10 in the at term children. HRT in preterm and at term children at term(n=28) preterm(n=25) P value mean sd mean sd Disc Area 2,5 0,7 2,34 0,68 0,38 Cup Area 0,50 0,44 0,58 0,47 0,51 Rim Area 2 0,45 1,76 0,37 0,047 C/D Area Ratio 0,18 0,12 0,22 0,14 0,23 C/D Linear Ratio 0,4 0,15 0,45 0,16 0,30 Mean RNFL Thick 0,2 0,07 0,24 0,2 0,26 Tab.1 A statistically significant reduction was found in preterm children as regard rim area (p=0,047,tab 1) at HRT and superior RNFL thickness (p=0,01), temporal and inferior inner macular thickness (p=0,03) at OCT. Differences in the pVep latencies were found at 3 and 8 months after birth, but not at the time of morphological examination. Steady State pVEP amplitudes differences were not statistically significant. Conclusion Morphologic optic disk and macula differences between term and preterm children seems not functionally affect the visual pathway. [source] Ganglion cell regeneration following whole-retina destruction in zebrafishDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2008Tshering Sherpa Abstract The retinas of adult teleost fish can regenerate neurons following injury. The current study provides the first documentation of functional whole retina regeneration in the zebrafish, Danio rerio, following intraocular injection of the cytotoxin, ouabain. Loss and replacement of laminated retinal tissue was monitored by analysis of cell death and cell proliferation, and by analysis of retina-specific gene expression patterns. The spatiotemporal process of retinal ganglion cell (RGC) regeneration was followed through the use of selective markers, and was found to largely recapitulate the spatiotemporal process of embryonic ganglion cell neurogenesis, over a more protracted time frame. However, the re-expression of some ganglion cell markers was not observed. The growth and pathfinding of ganglion cell axons was evaluated by measurement of the optic nerve head (ONH), and the restoration of normal ONH size was found to correspond to the time of recovery of two visually-mediated behaviors. However, some abnormalities were noted, including overproduction of RGCs, and progressive and excessive growth of the ONH at longer recovery times. This model system for whole-retina regeneration has provided an informative view of the regenerative process. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008 [source] In vitro evaluation of reactive astrocyte migration, a component of tissue remodeling in glaucomatous optic nerve headGLIA, Issue 3 2001Gülgün Tezel Abstract In order to improve understanding of remodeling events in the glaucomatous optic nerve head, the migration of optic nerve head astrocytes was studied in vitro. Since elevated intraocular pressure is an important stress factor identified in glaucomatous eyes, optic nerve head astrocytes were incubated under physical stress created by elevated hydrostatic pressure. In addition, they were incubated in the presence of a chemical stimulus, lipolysaccharide (LPS). Migration of reactivated astrocytes in the presence of these stressors was examined using chambers in which cell migration through extracellular matrix-coated pores is only possible following proteolytic digestion of the matrix. We observed that the migratory ability of optic nerve head astrocytes was approximately 4,6 times greater following exposure to elevated hydrostatic pressure or LPS for up to 48 h. Phosphoinositide 3-kinase, protein kinase C, and tyrosine kinase were found to be involved in the signal transduction for activated migration of optic nerve head astrocytes in response to elevated hydrostatic pressure or LPS. In addition, we observed that the stress-induced migration of optic nerve head astrocytes, which is accompanied by proteolytic degradation, resulted in the formation of culture cavities containing mucopolysaccharides. These in vitro findings provide a clearer understanding of the pathophysiologic mechanisms of characteristic tissue remodeling events that occur, in vivo, in the glaucomatous optic nerve head. GLIA 34:178,189, 2001. © 2001 Wiley-Liss, Inc. [source] Magnetic Resonance Imaging in Patients Diagnosed With Papilledema: A Comparison of 6 Different High-Resolution T1- and T2(*)-Weighted 3-Dimensional and 2-Dimensional SequencesJOURNAL OF NEUROIMAGING, Issue 2 2002Johannes Seitz MD ABSTRACT Purpose. To evaluate visualization and signal characteristics of macroscopic changes in patients with ophthalmologically stated papilledema and to find a suitable high-resolution magnetic resonance imaging (MRI) protocol. Method. Nine consecutive patients with 12 ophthalmologically stated papilledemas underwent MRI of the head and orbits, which consisted of the following high-resolution sequences: 3-dimensional (3D), T2*-weighted (T2*w) constructive interference in steady-state sequence (CISS); 3D, T1-weighted (T1w) magnetization prepared-rapid gradient echo sequence (MP-RAGE) (with and without intravenous contrast medium); transverse 3D and 2-dimensional (2D) (2mm), T2-weighted (T2w) turbo spin echo (TSE); transverse 2D (2mm), contrast-enhanced T1w TSE with fat-suppression technique; and transverse 2D (5mm), T2w TSE. A quantitative and qualitative evaluation of the papilla, optic nerve, optic nerve sheath, optic chiasm, and the brain was performed. The 6 high-resolution sequences were compared. Results. The elevation of the optic disc into the optic globe in ophthalmologically stated papilledema was best visualized in T2w, 3D CISS sequence. The pathological contrast enhancement was best seen in T1w contrast-enhanced 2D TSE sequence with fat-suppression technique. The mean width of the optic nerve sheath directly behind the globe was 7.54 mm (± 1.05 mm) in the pathological eyes, compared to 5.52 mm (± 1.11 mm) in the normal eyes. In all patients, the cerebral indices calculated showed no signs of increased intracranial pressure or other abnormalities changing the volume of the brain or ventricles. The contrast of the orbital fat versus the optic nerve sheath, the optic nerve sheath versus the surrounding cerebrospinal fluid (CSF), the surrounding CSF versus the optic nerve, the optic chiasm versus the CSF, and the optic papilla versus the optic globe were best visualized in the 3D, T2*w CISS sequence. An enhancement of the swollen optic nerve head was best seen in all 12 cases in the T1w contrast-enhanced 2D TSE sequence with fat-suppression technique. Conclusion. An MRI protocol consisting of a 5-mm transverse T2w TSE sequence; a T2*w, 3D CISS sequence; a T1w, 3D MP-RAGE sequence with and without contrast medium; and a transverse T1w, (2-mm) 2D TSE sequence with fat-suppression technique with intravenous contrast medium is suitable to visualize the macroscopic changes in papilledema. In addition, this combination is an excellent technique for the examination of the orbits and the brain. [source] Fluorescein leakage of the optic disc: time course in primary open-angle glaucomaOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 3 2010Niklas Plange Abstract Purpose:, To identify and quantify the time course of fluorescein leakage of the optic nerve head in primary open-angle glaucoma (POAG) and controls. Methods:, Twenty patients with POAG (aged 58 ± 10 years) and 14 controls (aged 51 ± 12 years, p = 0.07) were included in a prospective study. Fluorescein leakage of the optic disc was quantified using digital image analysis. A new leakage ratio (fluorescence of the optic disc divided by fluorescence of the surrounding retina) was defined and fluorescein leakage was quantified at 7,8, 9,10, 11,12, and 13,14 min after injection of 2.5 cc sodium fluorescein (10%). Results:, The fluorescein leakage exhibited a significantly different time course with higher leakage ratio values in POAG compared to controls (7,8 min: 1.24 ± 0.32 vs 1.16 ± 0.12; 9,10 min: 1.37 ± 0.37 vs 1.19 ± 0.1; 11,12 min: 1.38 ± 0.36 vs 1.24 ± 0.13; 13,14 min: 1.44 ± 0.36 vs 1.27 ± 0.13; p = 0.004). The change in optic disc fluorescence from 7,8 min to 9,10 min was significantly higher in POAG compared to controls (0.13 ± 0.09 vs 0.03 ± 0.07; p = 0.002). Conclusion:, The time course of fluorescein leakage is significantly different in POAG compared to controls. This might reflect damage of the optic disc vasculature related to increased vascular permeability. [source] Comparison of optical coherence tomography and fundus photography for measuring the optic disc sizeOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2006Aljoscha S. Neubauer Abstract Purpose:, To assess the agreement and repeatability of optic nerve head (ONH) size measurements by optical coherence tomography (OCT) as compared to conventional planimetry of fundus photographs in normal eyes. Methods:, For comparison with planimetry the absolute size of the ONH of 25 eyes from 25 normal subjects were measured by both OCT and digital fundus photography (Zeiss FF camera 450). Repeatability of automated Stratus OCT measurements were investigated by repeatedly measuring the optic disc in five normal subjects. Results:, Mean disc size was 1763 ± 186 vertically and 1632 ± 160 ,m horizontally on planimetry. On OCT, values of 1772 ± 317 ,m vertically (p = 0.82) and a significantly smaller horizontal diameter of 1492 ± 302 ,m (p = 0.04) were obtained. The 95% limits of agreement were (,546 ,m; +527 ,m) for vertical and (,502 ,m; +782 ,m) for horizontal planimetric compared to OCT measurements. In some cases large discrepancies existed. Repeatability of automatic measurements of the optic disc by OCT was moderately good with intra-class correlation coefficients (ICC) of 0.78 horizontally and 0.83 vertically. The coefficient of repeatability indicating instrument precision was 80 ,m for horizontal and 168 ,m for vertical measurements. Conclusions:, OCT can be used to determine optic disc margins in moderate agreement with planimetry in normal subjects. However, in some cases significant disagreement with photographic assessment may occur making manual inspection advisable. Automatic disc detection by OCT is moderately repeatable. [source] Expression of neuronal markers, synaptic proteins, and glutamine synthetase in the control and regenerating lizard visual systemTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 19 2010M.M. Romero-Alemán Abstract Spontaneous regrowth of retinal ganglion cell (RGC) axons occurs after optic nerve (ON) transection in the lizard Gallotia galloti. To gain more insight into this event we performed an immunohistochemical study on selected neuron and glial markers, which proved useful for analyzing the axonal regrowth process in different regeneration models. In the control lizards, RGCs were beta-III tubulin- (Tuj1) and HuCD-positive. The vesicular glutamate transporter-1 (VGLUT1) preferentially stained RGCs and glial somata rather than synaptic layers. In contrast, SV2 and vesicular GABA/glycine transporter (VGAT) labeling was restricted to both plexiform layers. Strikingly, the strong expression of glutamine synthetase (GS) in both Müller glia processes and macroglial somata revealed a high glutamate metabolism along the visual system. Upregulation of Tuj1 and HuCD in the surviving RGCs was observed at all the timepoints studied (1, 3, 6, 9, and 12 months postlesion). The significant rise of Tuj1 in the optic nerve head and optic tract (OTr) by 1 and 6 months postlesion, respectively, suggests an increase of the beta-III tubulin transport and incorporation into newly formed axons. Persistent Tuj1+ and SV2+ puncta and swellings were abnormally observed in putative degenerating/dystrophic fibers. Unexpectedly, neuron-like cells of obscure significance were identified in the control and regenerating ON-OTr. We conclude that: 1) the persistent upregulation of Tuj1 and HuCD favors the long-lasting axonal regrowth process; 2) the latter succeeded despite the ectopia and dystrophy of some regrowing fibers; and 3) maintenance of the glutamate-glutamine cycle contributes to the homeostasis and plasticity of the system. J. Comp. Neurol. 518:4067,4087, 2010. © 2010 Wiley-Liss, Inc. [source] Review Article: Ocular blood flow assessment using continuous laser Doppler flowmetryACTA OPHTHALMOLOGICA, Issue 6 2010Charles E. Riva Acta Ophthalmol. 2010: 88: 622,629 Abstract. This article describes the technique of continuous laser Doppler flowmetry (LDF) as applied to the measurement of the flux of red blood cells in the optic nerve head, iris and subfoveal choroid. Starting with the exposition of the physical principles underlying LDF, we first describe the various devices developed to perform LDF in these vascular beds. We then discuss the clinical protocols, blood flow parameters, calibration procedures, reproducibility and limitations of the LDF technique. Various problems still need to be solved in order to bring to light the full potential of LDF in the assessment of microcirculatory haemodynamics. [source] 4413: Analysis of gene expression in acute ischemic neuroretinas : a genome-wide screen discriminating occlusion (BRVO) versus laser effects in ratsACTA OPHTHALMOLOGICA, Issue 2010C OROPESA Purpose Identification of genes differentially regulated in rat neuroretinas submitted to an experimental acute branch retinal vein occlusion (BRVO), to a laser treatment, or to no treatment at all. Methods We have developed an in vivo experimental model of venous occlusion by photodynamic thrombosis in rat retinas. After anaesthesia, a sodium fluorescein solution was injected in rat tail 15 minutes before laser treatments. To induce ischemia in tested retina, venous sites adjacent to the optic nerve head were photocoagulated with an argon laser. In one group of tested animals, the retina was exposed to laser treatment at sites located between major vessels. As this treatment may have an effect upon choroidal blood flow, control eyes were not subjected to laser treatment. RNAs were isolated from the neuroretina 30 minutes post treatments, and processed for Affymetrix gene-chip analysis. Results Genome-wide screen enabled us to identify 308 and 348 genes which were up- or down-regulated, respectively, by BRVO and laser treatment only. When we compared the transcriptomes of retinas subjected to vessel occlusion or laser treatment to the control one, we found that the expression profiles of, respectively, 116 and 126 genes were specifically modified. The majority of the up- and down-regulated genes encode proteins involved in different aspects of early stress response, neuroprotection, inflammation and apoptosis. Conclusion Our microarray analysis revealed changes in gene expression bearing similarities to gene expression results from other ischemia models. Furthermore, it revealed that laser treatment may have an unreported impact on retina's metabolism. [source] 2221: Gases and the ocular vasculatureACTA OPHTHALMOLOGICA, Issue 2010L SCHMETTERER Purpose The regulation of ocular blood flow and oxygenation is largely controlled by metabolic factors. Among them gases like oxygen (O2), carbon dioxide (CO2), carbon monoxide (CO) and nitroc oxide (NO) play a key role. Methods In a series of clinical trials we focussed on the role of O2, CO2, CO and NO in the control of ocular blood flow. These studies were done on healthy subjects and employed a number of techniques including laser Doppler flowmetry, color Doppler imaging and pulsatile ocular blood flow techniques. Results O2 is a very potent vasoconstrictor in the retina and optic nerve head, but not in the choroid. The mechanisms underlying this effect is not entirely clear, but appears to involve endothelin A receptors. CO and CO2 are potent vasodilators in retina, choroid and optic nerve head. NO plays a major role in the control of basal vascular tone in all ocular vessels, but is also involved in many agonist-induced vasodilator effects. Conclusion Gases play a key role in controlling ocular blood flow. An imblanace of the production of these mediators is associated with ischemia, hypoxia and endothelial dysfunction. [source] 3253: Ocular neurovascular coupling in glaucoma patientsACTA OPHTHALMOLOGICA, Issue 2010K GUGLETA Purpose Defining property of glaucoma, cupping of the optic disc in parallel to loss of retinal ganglion cells and their axon, implies tissue remodeling of the optic nerve head which in turns requires involvement of astrocytes. Their malfunction may lead not only to cupping, but also to disturbance in ocular neurovascular coupling. Methods We analyzed 122 glaucoma patients, ocular hypertensives and healthy controls who all received no IOP-lowering therapy at least four weeks prior to the study examination. One eye per subject entered the primary analysis: in the POAG group, an eye with the biggest damage, in the OHT group an eye with the highest average IOP was selected. Relative vessel diameter increase in response to flicker light was used as the measure of neurovascular coupling. Results This response was impaired in untreated POAG patients, affecting both superior and inferior temporal retinal vessels. In general, inferior vessel dilated more than superior ones. The dilation amplitude was inversely correlated to the level of morphological (retinal nerve fiber layer thickness) and functional (visual field mean defect) glaucomatous damage. Despite the relatively high level of inter- and intraocular correlation of vessel responses, in a separate analysis of contralateral eyes, they seem to display higher dilation amplitudes than the more damaged eyes which were included in the original analysis. Conclusion Neurovascular coupling is impaired in untreated glaucoma patients. Prospective studies are underway in an attempt to clarify the cause versus consequence relationship between the glaucomatous damage and disturbance of neurovascular coupling. [source] 2114: AO adapted to SD-OCTACTA OPHTHALMOLOGICA, Issue 2010W DREXLER Purpose Optical coherence tomography (OCT) has emerged as a leading technique in ophthalmic imaging due to its capability to non-invasively resolve tissue morphology with high sensitivity and high axial resolution. Despite increases in axial resolution, monochromatic ocular aberrations limited the transverse resolution for retinal imaging to ~20 ,m, which is too large for visualization of cellular structures. Adaptive optics (AO) may be used to correct such aberrations, leading to an improvement in image contrast and lateral resolution. Methods A successful combination of ultra-high speed (120,000 depth scans/s), ultra-high resolution optical coherence tomography with adaptive optics and an achromatizing lens for compensation of monochromatic and longitudinal chromatic ocular aberrations, respectively, allows for non-invasive volumetric imaging in normal and pathologic human retinas at cellular resolution. Results The capability of this imaging system is demonstrated through preliminary studies by probing cellular intraretinal structures that have not been accessible so far with in vivo, non-invasive, label-free imaging techniques, including pigment epithelial cells, micro-vasculature of the choriocapillaris, single nerve fibre bundles and collagenous plates of the lamina cribrosa in the optic nerve head. In addition, the volumetric extent of cone loss in two colour-blinds can be quantified for the first time. Conclusion AO OCT might provide opportunities to enhance the understanding of retinal pathogenesis and early diagnosis of retinal diseases. Commercial interest [source] 2323: Role of nitric oxide in optic nerve head blood flow regulation during isometric exercise in healthy humansACTA OPHTHALMOLOGICA, Issue 2010D SCHMIDL Purpose Nitric oxide (NO) is an important regulator of optic nerve head (ONH) blood flow in humans. We have previously shown that NO is also involved in choroidal blood flow regulation during isometric exercise. Inhibition of NO synthase (NOS) has been reported to shift choroidal pressure,flow curves during squatting to the right. The hypothesis for the present study was that inhibition of NOS may also influence ONH blood flow during isometric exercise. Methods To test this hypothesis, a randomized, double-masked, placebo-controlled, three-way crossover study was performed in 18 healthy volunteers. Subjects received on different study days intravenous infusions of NG-monomethyl- L-arginine (L-NMMA), phenylephrine, or placebo. During these infusion periods, subjects were asked to squat for 6 minutes. ONH blood flow was assessed with laser Doppler flowmetry, and ocular perfusion pressure (OPP) was calculated from mean arterial pressure and intraocular pressure. Results L-NMMA and phenylephrine increased resting OPP (p < 0.001 versus baseline), but only L-NMMA reduced resting ONH blood flow (p = 0.02 versus baseline). The relative increase in OPP during isometric exercise was comparable with all drugs administered (p = 0.69). In addition, the change of ONH blood flow was comparable with all administered drugs (p = 0.43). Conclusion These data indicate that NO plays an important role in the regulation of ONH blood flow at baseline, but does not change the response of ONH blood flow during isometric exercise. [source] 4352: Retrobulber imag,ng in glaucoma w,th d,ffus,on tensor MRI/opt,c tractography and fMRI: structural and funct,onal analys,sACTA OPHTHALMOLOGICA, Issue 2010KN ENGIN Purpose Evidences today proves that, glaucomateus damage proceeds from retinal ganglion cells to brain. The purpose of this study is to demonstrate the structural and functional eye-brain connection in glaucoma, to develop favourable clinical methods for both glaucoma follow ups and large clinical trials, and finally, to establish a reference for further studies regarding pathogenesis, evaluation and treatment of glaucoma. Methods Four glaucoma cases with symetrical (n=2) and asymetrical (n=2) involvement and 1 healthy subject are included in this study. Glaucoma analysis with optic coherens tomography (OCT) and central visual field (CVF) results of the subjects were recorded. By using diffusion-tensor magnetic resonance imaging (DT-MRI) technique, 3D-T1 weighted images of the optic nerves and optic tracts were taken with optic tractography (OT). Then DT-MRI parameters obtained from each patient were compared with the fellow eye and the healthy subject. Retinotopic Organizations (RO) of primary visual cortexes were produced from functional magnetic resonance imaging (fMRI) images and BOLD signals were evaluated with reciprocal CVF defects. All images were taken with 1,5T MRI system. Results In DT-MRI analysis, optic nerve volume, FA were found to be decreased in the eyes with severe RNFL loss. Optic nerve and tract deformation were showed with both OT and B0 coronal plane images. Lower bold signals were detected in the eyes of asymetric patients with severe glaucoma and in quadrants with large CVF defects. Conclusion Strategies concerning beyond optic nerve head are needed in glaucoma. Structural and functional analysis can be made by taken together the OCT and DT-MRI findings and CVF and fMRI findings, respectively. [source] Acute visual loss after spinal surgeryACTA OPHTHALMOLOGICA, Issue 4 2010Jana Midelfart Hoff Abstract. Purpose:, To report visual loss after prone spinal surgery. Methods:, Computed tomography scan, fundus photography, optical coherence tomography (OCT). Results:, A 56-year-old man demonstrated loss of vision in the left eye after cervical spinal surgery. Clinical examination revealed loss of vision to finger counting, severe visual field defect and blurred neural rim area around the optic disc in the left eye. Six weeks later, visual acuity in the left eye was 6/9 and there was inferior visual field defect. Six months after the surgery, significant reduction of retinal nerve fibre layer thickness around the optic nerve head was measured with OCT, consistent with the visual field defect. Conclusion:, Ischemic optic neuropathy is the most common cause of visual loss after spine surgery and special emphasis should be given to protect the eye against possible pressure during the surgery. [source] Twelve-hour reproducibility of retinal and optic nerve blood flow parameters in healthy individualsACTA OPHTHALMOLOGICA, Issue 8 2009Alexandra Luksch Abstract. Purpose:, The aim of the present study was to investigate the reproducibility and potential diurnal variation of optic nerve head and retinal blood flow parameters in healthy individuals over a period of 12 hr. Methods:, We measured optic nerve head and retinal blood flow parameters in 16 healthy male non-smoking individuals at five time-points during the day (08:00, 11:00, 14:00, 17:00 and 20:00 hr). Outcome parameters were perimacular white blood cell flux (as assessed with the blue field entoptic technique), blood velocities in retinal veins (as assessed with bi-directional laser Doppler velocimetry), retinal arterial and venous diameters (as assessed with the retinal vessel analyser), optic nerve head blood flow, volume and velocity (as assessed with single point and scanning laser Doppler flowmetry) and blood velocities in the central retinal artery (as assessed with colour Doppler imaging). The coefficient of variation and the maximum change from baseline in an individual were calculated for each outcome parameter. Results:, No diurnal variation in optic nerve head or retinal blood flow was observed with any of the techniques employed. Coefficients of variation were between 1.6% and 18.5% for all outcome parameters. The maximum change from baseline in an individual was much higher, ranging from 3.7% to 78.2%. Conclusion:, Our data indicate that in healthy individuals the selected techniques provide adequate reproducibility to be used in clinical studies. However, in patients with eye diseases and reduced vision the reproducibility may be considerably worse. [source] Changes in optic nerve head blood flow induced by the combined therapy of latanoprost and beta blockersACTA OPHTHALMOLOGICA, Issue 7 2009Tetsuya Sugiyama Abstract. Purpose, To assess the effects of combined therapy with latanoprost and beta blockers on optic nerve head (ONH) blood flow in normal-tension glaucoma (NTG) patients. Methods, Intraocular pressure (IOP), ONH blood flow (laser speckle flowgraphy) and blood pressure were measured in 15 eyes of 15 NTG patients (41,76 years old) before treatment or after a 1-month washout period. Similar measurements were performed at 2 months after the commencement of treatment with latanoprost and at 3 months after the start of combined therapy of latanoprost with 0.5% timolol or 2% carteolol in a crossover study using the envelope method. Measurement was carried out 2,3 hr after the morning application of eyedrops. Results, Latanoprost decreased IOP with no significant change in ONH blood flow. Concomitant use of timolol or carteolol further decreased IOP with no significant difference between these two drugs. Only the combined therapy of latanoprost with carteolol significantly (p < 0.01) increased ONH blood flow by approximately 10%, compared to initial levels. There was no significant change in mean blood pressure, ocular perfusion pressure or pulse rate as a result of these therapies. Conclusion:, Topical latanoprost,carteolol combined therapy increased ONH blood flow in NTG patients, unlike latanoprost,timolol therapy. Because ocular perfusion pressure was unchanged, direct vasodilative effects were suspected as the mechanism. [source] Evidence for altered ocular rigidity in glaucomaACTA OPHTHALMOLOGICA, Issue 2009L SCHMETTERER Purpose Based on theoretical models and animal studies altered biomechanical properties of the optic nerve head and the sclera have been implicated in the pathophysiology of glaucoma. Only few data have, however, demonstrated such biomechanical alterations in vivo. We tested the hypothesis that patients with primary open angle glaucoma (POAG) have an abnormal structural stiffness based on measurements of intraocular pressure amplitude and ocular fundus pulsation amplitude. Methods Seventy patients with POAG and 70 healthy control subjects matched for age, gender, intraocular pressure and systemic blood pressure were included in this study. The ocular pulse amplitude (PA) was assessed with pneumotonometry. The fundus pulsation amplitude (FPA) was measured using laser interferometry. Based on the Friedenwald equation a coefficient of structural stiffness (E1) was calculated relating PA to FPA. Results Systemic blood pressure, intraocular pressure, and ocular perfusion pressure was comparable between glaucoma patients and healthy control subjects. FPA as well as PA was lower in patients with glaucoma than in healthy controls. The calculated factor E1 was significantly higher in patients with POAG (0.0454 ± 0.0085 a.u.) than in healthy control subjects (0.0427 ± 0.0058 a.u., p = 0.03). Conclusion This study is indicative of increased structural stiffness of the sclera in patients with POAG. This is in agreement with a number of previous animal experiments and supports the idea that the biomechanical properties of ocular tissues play a role in the process of glaucomatous ONH damage. [source] Retinal nerve fiber layer thickness and central corneal thickness in ocular hypertensive patients and healthy subjectsACTA OPHTHALMOLOGICA, Issue 2009AM BRON Purpose To establish the correlation between central corneal thickness (CCT) and retinal nerve fiber layer (RNFL) thickness in ocular hypertensive patients and healthy subjects. Methods We prospectively collected charts of healthy subjects and ocular hypertensive (OHT) patients in one academic center between 2007 and 2008. OHT patients were defined by two measurements of intraocular pressure superior to 21mmHg without treatment, open angle in gonioscopy, normal appearing optic nerve head and normal visual field test Standard Automated Perimetry (SAP SITA) and Frequency Doubling Technique (FDT). Every patient underwent a standard clinical examination including optic nerve head examination, intraocular pressure, CCT measurement by ultrasonic (US) and anterior segment OCT pachymetry, visual field testing (SAP and FDT), RNFL thickness by scanning laser polarimetry (GDX-VCC) and optical coherence tomography (OCT). Results Eighty healthy subjects and 60 OHT patients were included. A correlation between US CCT and OCT CCT was found in both groups (r2=0.85 and r2= 0.87, p<0.001). There was no significant difference (p>0.15) in GDX-VCC and OCT RNFL thickness in both groups. In controls there was no correlation of any RNFL thickness measurement with the CCT. In OHT patients, the US CCT was weakly correlated with the average TSNIT evaluated by GDX-VCC (r2= 0.04, p<0.02). Conclusion This study did not show any relevant correlation between the RNFL thickness evaluated by GDX-VCC and the US CCT in healthy individuals and in OHT patients with a normal FDT. [source] The retinal nerve fiber layer and the optic nerve head morphology after glaucoma surgeryACTA OPHTHALMOLOGICA, Issue 2009T GRACNER Purpose To detect and quantify changes in the retinal nerve fiber layer (RNFL) and the optic nerve head (ONH) morphology after glaucoma surgery. Methods 13 eyes of 13 patients with open-angle glaucoma in which goniotrephining with scleral flap without intraoperative antimetabolites for progressive glaucoma damage was done were included in this prospective study. Before and 6 months after the surgery: the intraocular pressure (IOP) was measured, the thicknes of the RNFL was measured with a scanning laser polarimeter (GDx VCC), the confocal scanning laser ophthalmoscopy measurements of ONH with Heidelberg retina tomograph (HRT 3) were performed and the visual field was tested with Humphrey Field Analyser. Results The mean IOP before surgery was 24.5 ? 2.3 mmHg decreasing 6 months after to a mean of 13.9 ? 3.0 mmHg (p<0.05). The RNFL measurements with GDx VCC revealed no differences between the mean TSNIT Avarage (p=0.383), mean Superior Avarage (p=0.756) and mean Inferior Avarage (p=0.269) before and after surgery. The ONH measurements with HRT 3 revealed postoperatively a significant increase in the mean Rim Area, Rim Volume and Cup Shape Measure, whereas Cup Area, Cup Volume and Linear Cup/Disc Ratio decreased (p<0.05). There were no differences between the mean Height Variation Contour (p=0.678) and Mean RNFL Thickness (p=0.064) before and after surgery. Preoperatively the mean value of the Mean Deviation on automated perimetry was ,18.82 ? 8.5 dB improving 6 months postoperatively to a mean of ,16.63 ? 7.9 dB (p<0.05). Conclusion Our study demonstrated the beneficial effect of IOP reduction obtained with glaucoma surgery on visual field indices and ONH parameters evaluated by HRT 3. [source] Effects of moxaverine on ocular blood flow in patients with age-related macular degeneration, patients with primary open angle glaucoma and in healthy controlsACTA OPHTHALMOLOGICA, Issue 2009B PEMP Purpose Several common eye diseases including age-related macular degeneration (AMD) and primary open angle glaucoma (POAG) are associated with ocular perfusion abnormalities. Moxaverine has been shown to increase ocular blood flow in young, healthy volunteers after intravenous administration. The present study investigated whether moxaverine alters ocular blood flow in elderly patients with AMD or POAG and in healthy control subjects. Methods 20 patients with AMD, 20 patients with POAG and 20 age-matched healthy subjects were included in this trial. 150 mg moxaverine (Ursapharm, Saarbrücken, Germany) was administered intravenously over 30 minutes. Systemic haemodynamics, retinal vessel diameters, choroidal, optic nerve head and retrobulbar blood flow were measured before and up to 90 minutes after drug administration. Results Administration of moxaverine increased choroidal blood flow by 8.7 ± 21.8% (p=0.012) and optic nerve head blood flow by 12.9 ± 33.3% (p=0.021). Additionally, an increase in the mean flow velocities of posterior ciliary arteries (24.8 ± 34.7%, p<0.001) and in the ophthalmic artery (23.3 ± 33.5%, p<0.001) was found after administration of moxaverine. However, no differences were found between the 3 study groups. No significant change of retinal vessel diameters was observed. Conclusion The present study indicates an increase of ocular blood flow after systemic administration of a single dose of moxaverine in patients with POAG, patients with AMD and in age-matched healthy controls. Further studies are needed to investigate possible beneficial effects after long-term treatment in patients with ocular diseases associated with hypoperfusion. [source] Hypovascular glial overgrowth from the optic nerve head in foetuses of 16 weeks gestationACTA OPHTHALMOLOGICA, Issue 3 2009Noriyuki Azuma No abstract is available for this article. [source] Endothelial dysfunction in glaucomaACTA OPHTHALMOLOGICA, Issue 1 2009Hemma Resch Abstract. Glaucoma is a group of ocular diseases characterized by optic neuropathy associated with loss of the retinal nerve fibre layer and re-modelling of the optic nerve head, and a subsequent particular pattern of visual field loss. Increased intraocular pressure is the most important risk factor for the disease, but the pathogenesis of glaucoma is not monofactorial. Among other factors, ischaemia and vascular dysregulation have been implicated in the mechanisms underlying glaucoma. The vascular endothelium plays an important role in the regulation of ocular blood flow and pathological alterations of vascular endothelial cells may induce ischaemia and dysregulation. The present review summarizes our current evidence of endothelial dysfunction in glaucoma. This is of interest because endothelial dysfunction is a good prognostic factor for progression in several diseases. Although such data are lacking for glaucoma, endothelial dysfunction may provide an attractive target for therapeutic intervention in open-angle glaucoma and other vascular disorders of the eye. [source] The multifocal electroretinogram (mfERG) in the pigACTA OPHTHALMOLOGICA, Issue 4 2007Maria Voss Kyhn Abstract. Purpose:, To establish a method allowing multifocal electroretinography (mfERG) recording with simultaneous fundus monitoring on anaesthetized pigs. In addition we characterize the peaks of the porcine mfERG trace, and compare the visual streak area with the optic nerve head, a known non-response area. Finally we illustrate the feasibility of the method by performing mfERG after an induced laser burn in the visual streak. Methods:, Fifteen pigs underwent mfERG recordings at baseline, and after 1 and 6 weeks of observation. One pig was evaluated before and after retinal diode laser treatment in the visual streak. Results:, The porcine mfERG trace appears similar to the human mfERG trace, and can be described by three peaks named N1, P1 and N2. Significantly faster implicit time was found in the visual streak regarding N1 (P < 0.001) than in areas outside the visual streak. Amplitudes of all three peaks were increased in the visual streak (P < 0.005). The laser-treated area was characterized by a response similar to what is found at the location of the optic nerve head. Conclusion:, Porcine mfERG is similar in appearance to the human response and can be described by the same three peaks. Significantly higher amplitudes of all three peaks are found in the visual streak when compared to the optic nerve head and inferior retina. We have detected the functional deficit caused by a laser burn at the size of 3 × 3 mm. [source] Microvascular blood flow of the optic nerve head and peripapillary retina in unilateral exfoliation syndromeACTA OPHTHALMOLOGICA, Issue 1 2004Ozcan Ocakoglu Abstract. Purpose:, To measure microvascular blood flow in patients with unilateral exfoliation syndrome (XFS) without glaucoma or ocular hypertension and to compare the values in the eyes with clinically detected exfoliation, their nonexfoliative fellow eyes of the same patients and control eyes. Methods:, Twenty-two patients with clinically detected unilateral XFS and 30 age-matched healthy subjects were included in this study. Group 1 consisted of 22 eyes with clinical XFS, and the nonexfoliative fellow eyes of the same patients formed Group 2. The control group (Group 3) comprised the randomly selected eyes of 30 age-matched healthy subjects. Ocular blood flow values (volume, flow and velocity) were recorded from the optic nerve head (ONH) and peripapillary retina (PPR) using the Heidelberg retinal flowmeter (HRF). The differences between the three groups were compared statistically. Results:, The mean values of blood flow obtained from the ONH and PPR in eyes with clinically detected exfoliation (Group 1) and their nonexfoliative fellow eyes (Group 2) were both significantly lower than the values for the control eyes (Group 3). The differences in ocular blood flow between the eyes with exfoliation and the nonexfoliative fellow eyes were not statistically significant [one-way analysis of variance (anova), Dunnett's T3 test, p , 0.05). Conclusion:, These findings suggest that the eyes with clinically detected unilateral XFS were associated with reduced blood flow values in both the ONH and the PPR. The nonexfoliative fellow eyes also have lower blood flow values than the control eyes. [source] The short-term effect of latanoprost on intraocular pressure and pulsatile ocular blood flowACTA OPHTHALMOLOGICA, Issue 1 2002Gerasimos T. Georgopoulos ABSTRACT. Purpose:, There is evidence that ocular blood flow plays a critical role in the clinical course of glaucoma. Any reduction in ocular blood flow due to topical antiglaucoma treatment should therefore be avoided. This study aimed to evaluate the short-term effect of local latanoprost application on ocular hemodynamics. Methods:, Intraocular pressure (IOP), ocular pulse amplitude (OPA), ocular pulse volume (OPV), systemic blood pressure, heart rate and the pulsatile component of ocular blood flow (POBF) were recorded using a pneumotonometer linked to the Langham Ocular Blood Flow System in 24 patients in a prospective, open-label study before and after 1 week of topical latanoprost application in both eyes. Twenty of the subjects had primary open-angle glaucoma and four had ocular hypertension. Results:, After 1 week of latanoprost treatment, IOP decreased significantly 6.2 ± 2.9 mmHg in OD (P < 0.001) and 6.2 ± 3.2 mmHg in OS (P < 0.001). Pulsatile OBF increased significantly by 201.2 ± 167.4 µL/min in OD (P < 0.001) and 203.8 ± 187.3 µL/min in OS (P < 0.001). Ocular pulse amplitude and OPV showed statistically significant increases (P < 0.05 and P < 0.001 respectively). Blood pressure and heart rate did not change significantly. Conclusion:, Our results indicate that 1 week after latanoprost application, POBF, OPA and OPV were significantly increased in the eyes treated. More information on the perfusion of the optic nerve head is needed before the relevance of these findings to optic nerve head blood flow can be interpreted correctly. [source] Short wavelength automated perimetryACTA OPHTHALMOLOGICA, Issue 6 2001John M. Wild ABSTRACT. Short Wavelength Automated Perimetry (SWAP) utilizes a blue stimulus to preferentially stimulate the blue cones and a high luminance yellow background to adapt the green and red cones and to saturate, simultaneously, the activity of the rods. This review describes the theoretical aspects of SWAP, highlights current limitations associated with the technique and discusses potential clinical applications. Compared to white-on-white (W-W) perimetry, SWAP is limited clinically by: greater variability associated with the estimation of threshold, ocular media absorption, increased examination duration and an additional learning effect. Comparative studies of SWAP and W-W perimetry have generally been undertaken on small cohorts of patients. The conclusions are frequently unconvincing due to limitations for SWAP in the delineation of abnormality and of progressive field loss. SWAP is almost certainly able to identify glaucomatous visual field loss in advance of that by W-W perimetry although the incidence of progressive field loss is similar between the two techniques. Increasing evidence suggests that functional abnormality with SWAP is preceded by structural abnormality of the optic nerve head and/or the retinal nerve fibre layer. SWAP appears to be beneficial in the detection of diabetic macular oedema and possibly in some neuro-ophthalmic disorders. [source] Simultaneous management of blood flow and IOP in glaucomaACTA OPHTHALMOLOGICA, Issue 4 2001Alon Harris ABSTRACT. Factors other than intraocular pressure (IOP) elevation must be involved in initiation and progression of glaucoma. An additional element in disease causation may be ischemia in the retina and optic nerve head. Ischemic damage to neurons in the CNS is similar mechanistically and histopathologically to changes seen in glaucoma. Further, glaucoma patients with normal IOP show clear evidence for cerebral and ocular ischemia. Aging and atherosclerosis reduce the ability of the eye to autoregulate blood flow when ocular perfusion pressure changes: the dependence of blood flow on perfusion pressure links ischemia to IOP. Consequently, neuroprotective treatments for glaucoma should be designed to both reduce IOP and improve ocular nutrient delivery. [source] An evaluation of the retinal nerve fiber layer thickness by scanning laser polarimetry in individuals with dementia of the Alzheimer typeACTA OPHTHALMOLOGICA, Issue 2 2001Hélène Kergoat ABSTRACT. Purpose: To determine, using scanning laser polarimetry, whether or not the retinal nerve fiber layer (RNFL) is altered in dementia of the Alzheimer type (DAT). Methods: Thirty individuals with mild to moderate DAT and 30 healthy age-matched controls participated in the study. Fundus images were acquired with a Nerve Fiber Analyzer. RNFL thickness measurements were obtained under an ellipse located 1.75 disc diameter from the optic nerve head (ONH) center. Results: No differences in RNFL thickness were observed between DAT and healthy subjects. The regional distribution of RNFL thickness was similar between the two test groups, with the RNFL being thickest in the superior and inferior retinal segments relative to the nasal and temporal regions. Conclusions: Our data indicate that the RNFL is not altered in DAT, at least in the earlier stages of the disease. [source] Mapping the surface astrocytes of the optic disc: a fluid-conducting role of the astrocytic covering of the central vesselsCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2010Francisco J Carreras MD PhD Abstract Background:, The vitreous interface of the optic nerve has been studied to delimit the covering of Elschnig's astrocytes and interstitial pathways of flow through the prelaminar region. Methods:, Perfusion of the prelaminar tissue under controlled pressure with a fluorescent marker injected into the vitreous cavity in pig eyes. The prelaminar region of the optic nerve and adjacent retina was fixed and flatmounted or frozen and cryosectioned and examined with the confocal laser microscope. Samples were also prepared for conventional transmission electron microscopy. Results:, The surface of the vitreous surface of the optic nerve is covered by a cobblestone-like pavement made of astrocytic projections. Intensely stained passages of different thickness indicate the presence of wide interconnected intercellular spaces in the covering of Elschnig's astrocytes. Those passages are absent in the intervascular areas occupied by axons and axon-linked astrocytes. Conclusions:, Delineation of the astrocytic pavement and the preferred flow routes formed by wide extracellular spaces are conspicuous features of the prelaminar region when examined with the confocal laser microscope and the help of sticky fluorescent tracer. This suggests that excess extracellular fluid can be interchanged with the vitreous by a network of interconnected extracellular spaces or preferred flow routes. Some pathogenic mechanisms can be related to fluid interchange in the optic nerve head. [source] | |||||||||||||