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Normal Vision (normal + vision)
Selected AbstractsRetinal neurodegeneration: early pathology in diabetesCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 1 2000Erich Lieth ABSTRACT Normal vision depends on the normal function of retinal neurons, so vision loss in diabetes must ultimately be explained in terms of altered neuronal function. However, to date relatively little attention has been paid to the impact of diabetes on the neural retina. Instead, the focus of most research has been primarily on retinal vascular changes, with the assumption that they cause altered neuronal function and consequently vision loss. An increasing body of evidence suggests that alterations in neuronal function and viability may contribute to the pathogenic mechanisms of diabetic retinopathy beginning shortly after the onset of diabetes. This view arises from neurophysiological, psychometric, histopathological and biochemical observations in humans and experimental animals. The collective evidence from past and recent studies supports the hypothesis that neurodegeneration, together with functional changes in the vasculature, is an important component of diabetic retinopathy. The authors invite other investigators to include the neural retina as a component of their studies so that the pathogenesis of diabetic retinopathy can be understood more clearly. [source] Nonvisible Insufficient Subcutaneous Reticular Venous Plexus Can Be Observed through the Skin Using a New Illumination MethodDERMATOLOGIC SURGERY, Issue 2010LUIS LOPEZ BUSTOS MD BACKGROUND Insufficient subcutaneous reticular venous plexus (ISRVP) is an overlooked disease because the human eye cannot see many of the insufficient veins. OBJECTIVE To present a total reticular vision (TRV) method that exposes nonvisible ISRVP to normal vision. METHOD & MATERIALS TRV used visual-spectrum white and red light of 700 nm and infrared light of 15 to 850 nm from an ultradigital viewer camera. We studied 124 asymptomatic subjects from the general population without visible ISRVP. Another six patients with ISRVP without other venous pathology were compared with six healthy controls, Very low pressure was applied to the proximal thigh, and minimal volume increments on the medial malleolus were photoplethysmographically registered to validate subcutaneous venous reflux. RESULTS Total reticular vision exposed ISRVP on the lower extremities in 72 of 124 subjects (58%), with observed damaged veins corresponding to more than 90% of nonvisible and 5% of visible portions of ISRVP. Subcutaneous reflux was registered only in patients with ISRVP. CONCLUSION Total reticular vision exposed more than 90% of nonvisible ISRVP, a new pathology, allowing for the study of its relationship with other superficial venous insufficiencies. The authors have indicated no significant interest with commercial supporters. [source] Voxel-based analysis of MRI detects abnormal visual cortex in children and adults with amblyopiaHUMAN BRAIN MAPPING, Issue 2 2005Janine D. Mendola Abstract Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity. Anatomic magnetic resonance imaging (MRI) and psychophysical vision testing was carried out on 74 subjects divided into two age ranges, 7,12 years and 18,35 years, and three diagnoses, strabismic amblyopia, anisometropic amblyopia, and normal vision. We report a behavioral impairment in contrast sensitivity for subjects with amblyopia, consistent with previous reports. When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex. This finding was confirmed with a separate region-of-interest analysis. For the children with amblyopia, additional gray matter reductions in parietal-occipital areas and ventral temporal cortex were detected, consistent with recent reports that amblyopia can result in spatial location and object processing deficits. These data are the first to provide possible neuroanatomic bases for the loss of binocularity and visual sensitivity in children and adults with amblyopia. Hum Brain Mapp 25:222,236, 2005. © 2005 Wiley-Liss, Inc. [source] Pulfrich's phenonenon in a case of optic nerve hypoplasiaOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2008Gordon Heron Introduction:, Optic nerve hypoplasia (ONH) is a congenital deficiency of retinal ganglion cells and their axons that form the optic nerve. This condition is associated with visual deficits ranging from no light perception in severe cases to vision within normal ranges in mild cases of ONH. In mild cases, deficits can be limited to sectoral anomalies in the visual field and normal vision with colour vision anomalies have been reported. We report here a case of mild ONH with visual symptoms relating to Pulfrich phenomenon (PP) occurring spontaneously. Methods:, A 12 year girl presented with typical visual symptoms (bumping into objects when walking, poor object location at tennis) associated with the spontaneous PP. A simple pendulum revealed a perceived anticlockwise ellipse indicative of a left eye defect. This was neutralised by an 85% transmission filter placed before the right eye. The inter-ocular latency difference was calculated to be 0.88 (S.D., 0.55) ms. Results:, Fundus biometry showed an asymmetry in optic nerve size, the left being smaller than the right. Visual fields, anomaloscope and other colour vision tests, and both flash and pattern-reversal stimuli Visually Evoked Potentials showed no difference in visual function between the right and left eyes. Conclusions:, A case of very mild ONH gives inter-ocular normal vision and visual function and yet a subtle inter-ocular delay occurs resulting in visual symptoms associated with PP. These were completely removed with tinted spectacles. [source] Effect of light filters on reading speed in normal and low vision due to age-related macular degenerationOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2004Frank Eperjesi Abstract Purpose:, To investigate the effects of light filters on reading speed in normal and low vision due to age-related macular degeneration (AMD). Methods:, Reading speed was determined for 12 subjects with normal vision and 12 subjects with non-exudative AMD using stationary lowercase nonsensical print in Times Roman font and four light filters; a yellow Corning Photochromic Filter (CPF) 450, a grey neural density (ND) filter, an individual filter obtained using the Intuitive Colorimeter® and a clear filter. Results:, There was no statistically significant light filter effect on reading speed for the normal subjects. The AMD group demonstrated a statistically significant 5% average improvement in reading speed with the CPF450 compared with the other filters although some AMD subjects had improvements of 10,15%. Conclusions:, Light filters obtained using the Intuitive Colorimeter® performed poorly when compared with the CPF450, ND and clear filters for both the study groups. For the AMD group, average reading speed was statistically greater with the CPF450 than the other filters, however it is questionable whether the improvement (5%) would be clinically significant. As some of the subjects with AMD had greater improvements with the CPF450 we advocate clinical assessment of light filters using existing protocols on an individual basis. [source] What do patients with glaucoma do when they search and look at everyday scenes?ACTA OPHTHALMOLOGICA, Issue 2009ND SMITH Purpose To test the hypothesis that patients with bilateral glaucoma exhibit different eye movements compared to normally-sighted subjects when viewing computer displayed photographs, or searching for features or items within them. Methods Thirteen glaucoma patients and 17 age-matched subjects with normal vision viewed 28 randomised digital photographs of various everyday scenes displayed on a computer screen for 3 seconds each. Subjects were instructed to view the images as they would when looking at a slideshow. The subjects then viewed another set of images, but were timed to find a feature or item in the scene. Eye movements were simultaneously recorded using an Eyetracking system. Results In the passive viewing experiment, there was a significant reduction in the average number of saccades for glaucoma patients compared to controls (p<0.0001). In addition, average fixation duration was longer and the average area scanned was more restricted in patients compared to controls. In the search task glaucoma patients took, on average, longer to find the objects (p<0.0001) compared to controls. For this task, saccades were still reduced in number. In some cases, individual scanning patterns appeared related to the type and nature of the binocular visual field defect. Conclusion Eye movement behaviour in patients with glaucomatous defects in both eyes differ from normal-sighted subjects when viewing images and photographs. These patients with glaucoma find it more difficult to locate items within scenes compared to normally sighted subjects. Acknowledgements: This work is generously supported by an unrestricted grant from the Special Trustees of Moorfields Eye Hospital. [source] Sensory ocular dominance based on resolution acuity, contrast sensitivity and alignment sensitivityCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 1 2009Catherine Suttle PhD MCOptom Background:, Ocular dominance is the superiority or preference of one eye over the other in terms of sighting, sensory function (for example, visual acuity) or persistence in binocular rivalry. There is poor agreement between sighting and sensory dominance and findings are equivocal on the possible neural basis of ocular dominance and its significance. Thus, there are questions on the meaning and importance of ocular dominance. Despite the lack of clarity in this area, ocular dominance is used clinically, for example, as the basis for decisions on monovision in contact lens wear and on treatment of anomalies of binocular vision. Methods:, Sighting dominance and three types of sensory dominance (based on resolution acuity, contrast sensitivity and alignment sensitivity) were compared within individuals, with the main aim of determining whether sensory dominance is consistent across spatial visual functions. Results:, Our findings indicate that each type of sensory dominance is insignificant in most individuals and in agreement with previous work that sensory and sighting dominance do not generally agree. Conclusion:, These results demonstrate not only that different types of ocular dominance are not in agreement but also that in the normal visual system sensory dominance as measured here is insignificant in most individuals with normal vision. [source] | ||||||||||