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A number of studies have demonstrated atypical perception in individuals with ASD. However, the majority of these studies have presented stimuli to central vision. The aim of the study presented here was to test the sensitivity of peripheral vision in ASD. This was achieved by asking participants to detect brief flashes of light presented between 30 and 85 degrees away from fixation. We found that participants with ASD detected fewer light-flashes than the control participants. This deficit was more pronounced in the nasal hemifield than the temporal hemifield. We suggest that the imbalance between nasal and temporal hemifield sensitivity may contribute to the peripheral-field stimulation and lateral glances that are observed in ASD. Keywords Vision * Peripheral visual field * Nasal hemifield * Temporal hemifield * Dorsal stream * Ventral stream * Rods * Cones * Perception * Autism spectrum disorder, Introduction While the primary symptoms of autistic spectrum disorder (ASD) are associated with impairments in social behaviour, communication and imagination, many individuals with ASD also report abnormality in sensory processing [...]

Background. Despite sensational news reports, few studies have quantified the rates of poor driving performance among older drivers and the predictors of poor performance. We determined the rate of running red traffic lights among older drivers and the relationship of failure to stop to measures of vision and cognition. Methods. Multiple measures of vision and cognition were collected at the baseline examination of a population of 1,425 drivers aged 67-87 years in greater Salisbury, Maryland. Each driver had real-time data collected on 5 days of driving performance at baseline and again at l year. Failure to stop at a red traffic light was the primary outcome. Results. Overall, 3.8% of older drivers failed to stop at red traffic lights, with 15% of those who ran the light having failed 10% or more of the traffic lights they encountered. A narrowing of the attentional visual field (AVF; the extent of peripheral vision in which objects are detected while attention is also centrally fixated) was associated with failure to stop at traffic fights at baseline and predictive 1 year later (incidence rate ratio = 1.09 per degree lost, 95% confidence interval = 1.01-1.16). Persons with smaller vertical AVF were more likely to fail to stop. No demographic or vision variable was related to failure to stop. Conclusions. Failure to stop at red lights was a relatively uncommon event in older drivers and associated with reduced ability to pay attention to visual events in the vertical field of vision. Key Words: Vision--Visual attention--Cognition--Driving--Older population. doi:10.1093/gerona/glp136

Classical receptive-field concepts have been used to explain local perceptual effects such as border contrast and Mach bands, but are not sufficient to explain global perceptual effects. Examples are the perception of illusory contours, area contrast, color constancy, depth planes, coherent motion and texture contrast. These diverse effects require neurophysiological mechanisms within the visual pathways with long-range interactions. Candidate mechanisms are suggested, including converging feedforward projection to account for the emergence of new response properties at higher levels, recruitment of lateral connections to compensate for loss of afference and explain filling-in, and re-entrant projections from higher levels using synchronization of neuronal responses to account for binding.

Primary biliary cirrhosis is a rare, progressive form of cirrhosis (degenerative disease of the liver) caused by chronic retention of bile and inflammation of the bile ducts. This biliary cirrhosis, which usually occurs in women between 40 and 60 years of age, causes enlargement of the liver and spleen, weight loss, and pruritus (itching). The retention of bile is believed to be the result of a process in which the body's immune system causes destruction of the small bile ducts within the liver. Jaundice is a sign of progressive liver disease, and about one quarter of patients have vitamin A deficiency. Chronic liver disease can result in significant vitamin A deficiency, causing eye complications, including restriction of the field of peripheral vision. Intramuscular injections of vitamin A may reverse the visual field loss; it has been suggested vitamin A taken by mouth is more effective. A case is presented of a 51-year-old woman with primary biliary cirrhosis who developed gradual deterioration of vision in her left eye. She was receiving intramuscular injections of vitamin A. Eye examination revealed severe restriction of peripheral visual fields with some abnormalities of color vision. The fundus (back of the inner eye) showed changes indicative of vitamin A deficiency. The patient's general condition deteriorated with development of jaundice; at this point she received a liver transplant. This produced rapid improvement in her general condition, and six months later eye examination revealed improvement in her peripheral field of vision and color vision. These results support the view that vitamin administered via intramuscular injections does not result in improved vision. (Consumer Summary produced by Reliance Medical Information, Inc.)

Purpose: When the optic disc has normal appearance with no abnormalities in routine automated perimetry, the subject is not considered to have glaucoma. The purpose of this study is to show how such patients may have localized retinal nerve fiber layer defects with corresponding functional abnormality. Methods: The authors selected eight eyes of eight patients who had a localized retinal nerve fiber layer defect extending within a few degrees from fovea but in whom the optic disc appearance and Humphrey 30-2 visual fields were normal. Of the eight patients, three had positive family history of glaucoma, two had suspected retinal nerve fiber layer abnormality in routine eye examination, two had increased intraocular pressure (IOP), and one had advanced low-tension glaucoma in one eye with a normal fellow eye. The authors examined the central 10[degrees] visual field with 1[degree] resolution using Humphrey perimeter and the Ring and Centring programs of the high-pass resolution perimeter. Results: A central field defect corresponding to retinal nerve fiber layer defect was found in six of eight patients: in both 10[degrees] Humphrey field and Centring programs (2 eyes), in Humphrey only (2 eyes), and in Centring only (2 eyes). Conclusion: The results indicate that retinal nerve fiber layer photographs are helpful in diagnosing glaucoma because early glaucomatous abnormalities cannot be excluded without nerve fiber layer photography. Currently available routine perimetric examination programs do not always detect very early functional damage. (1993;100:587-598) Anja Tuulonen et al, Department of Ophthamology, University of Oulu, Oulu, SF-90220 Finland.