De Moraes C.G.,New York University |
De Moraes C.G.,Einhorn Clinical Research Center
Journal of Glaucoma | Year: 2013
The axons of the retinal ganglion cells form the optic nerve. The two optic nerves meet at the optic chiasm, where the nerve fibers originating in the nasal retina of each eye decussate to join the temporal fibers of the fellow eye. From the chiasm, the same axons continue on as the optic tract. These axons travel to and synapse in the lateral geniculate nucleus, the cells of which send their axons through the optic radiations to the visual cortex. The main blood supply to visual cortex is provided by the posterior cerebral arteries and their branches (the calcarine, posterior temporal, and parieto-occipital arteries). At the occipital pole, however, there may be a dual blood supply to the area subserving central vision, with anastomoses between branches of the posterior cerebral arteries and the superior temporo-occipital branch from the middle cerebral artery. Copyright © 2013 by Lippincott Williams & Wilkins.
Mari J.M.,University of Lyon |
Strouthidis N.G.,University College London |
Strouthidis N.G.,Singapore Eye Research Institute |
Park S.C.,Einhorn Clinical Research Center |
And 3 more authors.
Investigative Ophthalmology and Visual Science | Year: 2013
PURPOSE. We improved the visibility of the lamina cribrosa (LC), including its posterior boundary, in optical coherence tomography (OCT) images of the human optic nerve head (ONH). METHODS. An adaptive compensation algorithm was developed to overcome a limitation of our standard compensation algorithm, that is the overamplification of noise at high depth. Such limitation currently hampers our ability to distinguish the posterior LC boundary. In adaptive compensation, standard compensation operations are performed until an energy threshold is reached, at which stage the compensation process is stopped to limit noise overamplification in the deeper portion of the OCT image. The performance of adaptive compensation was compared to that of standard compensation using OCT images of 5 human ONHs. RESULTS. Adaptive compensation significantly reduced the intralayer contrast (a measure of pixel intensity uniformity) in the deeper portion of the OCTimages (from 0.62±0.11-0.30±0.03, P < 0.001), indicating successful removal of noise overamplification. Furthermore, adaptive compensation significantly increased the interlayer contrast (ameasure of boundary visibility) across the posterior LC boundary (from0.29±0.13-0.61±0.21, P<0.001), indicating improved posterior LC boundary visibility. CONCLUSIONS. Adaptive compensation provided significant improvement compared to standard compensation by eliminating noise overamplification at high depth and improving the visibility of the posterior LC boundary. These improvements were performed while maintaining all other benefits of compensation, such as shadow removal and contrast enhancement. Adaptive compensation will help further our efforts to characterize in vivo ONH biomechanics for the diagnosis and monitoring of glaucoma. © 2013 The Association for Research in Vision and Ophthalmology, Inc.
Ritch R.,Einhorn Clinical Research Center
Journal of Glaucoma | Year: 2014
Exfoliation syndrome is an age-related disease characterized by the production and progressive accumulation of a fibrillar extracellular material in many ocular tissues. It leads to the most common identifiable cause of open-angle glaucoma worldwide, comprising the majority of glaucoma in some countries. The material in the eye appears as white deposits on the anterior lens surface and/or pupillary border. During pupillary movement, the iris scrapes exfoliation material from the lens surface, while the material on the lens causes rupture of iris pigment epithelial cells, with concomitant pigment dispersion into the anterior chamber and its deposition on anterior chamber structures. Exfoliation material can be found in many different organs. It is an ischemic disease and is associated with elevated serum homocysteine. Systemic associations include transient ischemic attacks, hypertension, angina, myocardial infarction, cerebrovascular and cardiovascular disease, aortic aneurysm, Alzheimer disease, and hearing loss. The discovery in 2007 of nonsynonymous single nucleotide polymorphisms in the LOXL1 (lysyl oxidase-like 1) gene are expected to make a major impact not only in understanding exfoliation syndrome, but in leading to new avenues of therapy. Copyright © 2014 by Lippincott Williams & Wilkins.
Thonginnetra O.,Einhorn Clinical Research Center
Journal of glaucoma | Year: 2010
To compare visual field defects obtained with both multifocal visual evoked potential (mfVEP) and Humphrey visual field (HVF) techniques to topographic optic disc measurements in patients with normal tension glaucoma (NTG) and high tension glaucoma (HTG). We studied 32 patients with NTG and 32 with HTG. All patients had reliable 24-2 HVFs with a mean deviation of -10 dB or better, a glaucomatous optic disc and an abnormal HVF in at least 1 eye. Multifocal VEPs were obtained from each eye and probability plots created. The mfVEP and HVF probability plots were divided into a central 10-degree radius and an outer arcuate subfield in both superior and inferior hemifields. Cluster analyses and counts of abnormal points were performed in each subfield. Optic disc images were obtained with the Heidelberg Retina Tomograph III. Eleven stereometric parameters were calculated. Moorfields regression analysis and the glaucoma probability score were performed. There were no significant differences in mean deviation and pattern standard deviation values between NTG and HTG eyes. However, NTG eyes had a higher percentage of abnormal test points and clusters of abnormal points in the central subfields on both mfVEP and HVF than HTG eyes. For Heidelberg Retina Tomograph III, there were no significant differences in the 11 stereometric parameters or in the Moorfields regression analysis and glaucoma probability score analyses of the optic disc images. The visual field data suggest more localized and central defects for NTG than HTG.
Jonas J.B.,University of Heidelberg |
Jonas J.B.,Capital Medical University |
Wang N.,Capital Medical University |
Yang D.,Capital Medical University |
And 2 more authors.
Progress in Retinal and Eye Research | Year: 2015
The orbital cerebrospinal fluid pressure (CSFP) represents the true counter-pressure against the intraocular pressure (IOP) across the lamina cribrosa and is, therefore, one of the two determinants of the trans-lamina cribrosa pressure difference (TLPD). From this anatomic point of view, an elevated TLPD could be due to elevated IOP or abnormally low orbital CSFP. Both experimental and clinical studies have suggested that a low CSFP could be associated with glaucomatous optic neuropathy in normal-pressure glaucoma. These included monkey studies with an experimental long-term reduction in CSFP, and clinical retrospective and prospective studies on patients with normal-pressure glaucoma. Since the choroidal blood drains via the vortex veins through the superior ophthalmic vein into the intracranial cavernous sinus, anatomy suggests that the CSFP could influence choroidal thickness. A population-based study revealed that thicker subfoveal choroidal thickness was associated with higher CSFP. Since the central retinal vein passes through the orbital CSF space, anatomy suggests that the retinal venous pressure should be at least as high as the orbital CSFP. Other experimental, clinical or population-based studies suggested an association between higher CSFP and higher retinal venous pressure and wider retinal veins. Consequently, a higher estimated CSFP was associated with arterial hypertensive retinopathy (with respect to the dilated retinal vein diameter and higher arterial-to-venous diameter) and with the prevalence, severity and incidence of diabetic retinopathy. Physiologically, CSFP was related with higher IOP. The influence of the CSFP on the episcleral venous pressure and/or a regulation of both CSFP and IOP by a center in the dorsomedial/perifornical hypothalamus may be responsible for this. Insummary, the CSFP may be an overlooked parameter in ocular physiology and pathology. Abnormal changes in the CSFP, in particular in relationship to the IOP, may have pathophysiologic importance. © 2015 Elsevier Ltd.