1/5. exercise-induced visual loss associated with advanced glaucoma in young adults.PURPOSE: To highlight the phenomenon of exercise-induced visual loss associated with advanced glaucoma and to discuss the possible underlying mechanisms. methods: Three young adult patients with congenital or juvenile-onset glaucoma presenting with visual loss which occurred during exercise underwent ophthalmic examination. In 2 cases, visual function parameters, including visual fields (Humphrey full threshold perimetry) were measured before and after exercise. RESULTS: All patients clearly described visual loss during exercise. In the 2 cases in which data were available, significant impairment in central visual acuity and reduced foveal sensitivity and mean deviation on visual field analysis occurred during exercise of mild to moderate intensity with complete or near complete recovery of visual function upon cessation of exercise. CONCLUSION: Young patients with advanced glaucomatous optic neuropathy should be questioned regarding exercise-induced visual disturbance. We hypothesise that a 'vascular steal' is the likely mechanism underlying this phenomenon. patients should be advised to limit activities which induce their symptoms, and therapeutic measures to promote ocular blood flow should be considered.- - - - - - - - - - ranking = 1keywords = near (Clic here for more details about this article) |
2/5. 'When is VISION asked too much'?The last two decades a shift took place from substitutional/compensatory training to utilisation of residual vision regarding rehabilitation of the visually impaired. Some of the visually impaired are able to use their visual perception nearly as complete as normal seeing people in spite of a severe visual disability. On the other hand, people with nearly normal functions can be severely visually handicapped. To illustrate this, two cases are presented. The first case is a man, aged 47 years, with a juvenile macular degeneration on both eyes. In spite of a very low visual acuity of less then 0.05, he finished an university education and he is able to maintain himself very well in a leading position in a scientific environment, by using adequate low vision devices. Also for his leisure activities, as photography and speed skating, he relies upon visual perception. The second case is a woman, aged 30 years, with nearly normal visual functions, who is not able to read for longer periods caused by conflicting information from the body- and eye movements, and the visual input. This causes sickness during reading. She is unable to use books for her study and is working with recordings on tape. The results of a comprehensive visual assessment will be related to the specific low vision devices and its use.- - - - - - - - - - ranking = 3keywords = near (Clic here for more details about this article) |
3/5. Modification of the UniVision lens for a low-vision bifocal user.BACKGROUND: A 5-year-old Hispanic male with an ocular history of retinopathy of prematurity was seen for an evaluation of his functional abilities and a determination of the possible treatment options for rehabilitation. The greatest concern was to provide the boy with the tools necessary to ensure success in the educational system. methods: A low-vision evaluation was performed and baseline information was obtained, including distance visual acuities, near visual acuities, visual fields and refractive error. This data was then used to determine if, in a classroom setting, the child would encounter any difficulties that could benefit from assistive optical devices or modifications of environment. RESULTS: The child demonstrated a large angle of head turn in order to eccentrically view to obtain his best visual acuity. His refractive error had no effect on this visual acuity at distance. Visual acuities taken at near demonstrated a working distance of 4 cm with preference to using the right eye. A gross confrontation field suggested a relatively full field in the right eye, but a temporal field loss in the left eye. CONCLUSIONS: A monocular bifocal system was prescribed for use in the classroom and at home when studying. The bifocal segment was a round 24 diopter aspheric lens, 22 mm in diameter, which was reshaped into a flat-top and adhered to a carrier lens. The carrier lens was ordered with 10 prism diopters base left in each eye. This system addressed both the large eccentric viewing position and the magnification necessary to alleviate the accommodative system.- - - - - - - - - - ranking = 2keywords = near (Clic here for more details about this article) |
4/5. Visual-field measurements and driving eligibility.BACKGROUND: A 50-year-old black man with an ocular history of open-angle glaucoma was seen for a vision rehabilitation examination, with goals of improving his vision for work and determining his eligibility for driving. He was referred to the clinic through state services for the visually impaired. methods: A low-vision evaluation was performed and baseline information was obtained, including distance- and near-visual acuities, visual fields, and subjective refraction. This information was used to determine if he was eligible for services and if any low-vision devices would benefit him. RESULTS: The patient demonstrated moderately decreased visual acuity in the right eye (6/15) and very reduced visual acuity in the left eye (6/120). His visual fields varied depending on the test performed, ranging from 85 degrees to 140 degrees horizontal diameter. He was able to remove his spectacles and perform near tasks quite well. CONCLUSIONS: The patient was counseled that if he used one of the field tests he could qualify for services, but if he chose the other test he would qualify for driving and not qualify for services. The ramifications of using different field tests and understanding their parameters when assessing eligibility for services and benefits can be significant.- - - - - - - - - - ranking = 2keywords = near (Clic here for more details about this article) |
5/5. Visual symptoms with dural arteriovenous malformations draining into occipital veins.OBJECTIVE: To determine the cause of the visual dysfunction and effect of treatment on dural arteriovenous malformations (DAVMs) that secondarily involve the occipital lobe. BACKGROUND: DAVMs are an infrequent cause of visual dysfunction that should be amenable to treatment if diagnosed before permanent visual field loss. methods: The records of seven patients with cerebral visual disturbances associated with DAVMs were analyzed with attention to visual symptoms, visual field testing, and vascular anatomy. RESULTS: Sudden visual loss occurred in five patients, two with a hemorrhage and one with a venous infarct in the occipital lobe. Fortification images occurred in three patients, two of whom had palinopsia (one with de novo formed visual hallucinations). Homonymous quadrantic or hemianoptic field defects, some fluctuating, were found in six patients. angiography revealed each DAVM was supplied solely by dural arteries and drained into occipital pial veins due to retrograde blood flow through the sites near or in the wall or lumen of the dural venous channels that normally drain the occipital lobe. Unlike DAVMs in other locations, only two patients had occlusion of an adjacent venous sinus. These patients, particularly the two with posterior fossa DAVMs remote to the occipital lobe, clearly demonstrate the visual and neurologic dysfunction resulting from venous hypertension. In six patients, intra-arterial embolization of the arterial feeders and nidus (one patient required additional surgery) resulted in resumption of normal occipital venous emptying. No further visual episodes occurred in five of these six patients. The visual fields normalized in three patients and improved in one with venous infarct but were unchanged in both patients with a hemorrhage. CONCLUSIONS: DAVMs that drain into occipital veins cause field loss and other visual disturbances because of venous hypertension in the occipital lobe, which can be reversed by occluding the DAVM nidus. If a venous infarct or hemorrhage has not caused irreversible damage, visual recovery should be complete.- - - - - - - - - - ranking = 1keywords = near (Clic here for more details about this article) |