ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Objective:To compare the comprehensive care plan assessment (Minimum Data Set, MDS) of vision with the clinically evaluated visual status of nursing home residents to determine the accuracy of the vision care plan.Design:Descriptive study.Setting:One publicly funded and four privately owned long-term care nursing facilities.Participants:151 nursing home residents undergoing vision examination at the nursing home request. Mean age of 81, range 34 to 97 years.Main Outcome Measure:The charted MDS assessment for vision patterns was compared with the MDS plan which would have been formulated based on direct clinical vision examination. Determinations were made based on the three areas required by MDS: visual acuity (VA), peripheral vision, and presence of prosthetic visual devices.Conclusions:The MDS care plan for vision and actual visual status agreed in only 34% (52/151) of persons. The Vision (VA) subsection overestimated VA in 41 % and underestimated VA in 11%. Concordance for VA was extremely poor (kappa 0.176). In no participants did the MDS indicate a visual field defect, whereas 16.5% (25/151) did show visual field restriction on examination. Care plan assessments also failed to note the use of visual prosthetic devices in 17% (26/151). These results indicate that MDS care plan assessment for vision is often inaccurate and may result in the lack of appropriate vision care being triggered through resident assessment protocols (RAP).

ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

This study addressed the issue of prevalence and pattern of visual deficits in 77 subjects with Alzheimer's disease (AD) and 111 healthy control subjects. We defined cutoff scores that would be expected from only 1 control subject of 100 (p=0.01). The percentage of AD subjects who performed at or worse than this level varied across the 16 visual tests from a high of 58% to a low of 0%. The distribution of impairment across tests suggests a high vulnerability in AD of pattern vision, moderate vulnerability of spatial vision, and low vulnerability of motion and flicker perception. We found evidence for heterogeneity in the AD subject group: a subgroup (N =14) emerged that was characterized by poor performance on the Backward Pattern Masking test, relatively young age, and relatively short duration of AD. Overall, the results indicate that visual dysfunction, especially on Backward Masking, is a common sign of AD.

ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Deficits in basic visual capacities are prevalent in Alzheimer's disease (AD), raising the question of their impact on cognitive function. We examined the relation between vision and cognition in 72 patients with AD. Vision tests assessed color discrimination, stereoacuity, contrast sensitivity, and backward pattern masking. For cognitive tests of object recognition, at least 25% (up to 50%) of score variance was predicted by performance on a vision test. For tests of spatial localization, only 2 to 11 % of the variance was predicted by performance on a vision test. The results indicated that: (1) visual dysfunction was a significant predictor of cognitive dysfunction in AD, and (2) visual deficits in AD may have a strong functional impact on performance in specific cognitive domains.

ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The relative luminous efficiency curves for light entering different parts of the entrance pupil [Stiles- Crawford functions (SCFs)] of subject TG, whose right eye is amblyopic, were determined earlier for both the normal and the amblyopic eye. The left eye was found to have a normal SCF, varying from the center to the edge of the entrance pupil by an entire log unit. However, the SCF for the right eye was found to be abnormal, showing peak sensitivity far toward the temporal edge of the pupil and varying from center to edge by only one-third of a log unit. From these data it was inferred that the photoreceptors were in poor alignment. In October, 1993 the subject experienced a retinal detachment in the left (nonamblyopic) eye, requiring cryoretinopexy, drainage of subretinal fluid, and a scleral buckle. Postoperatively, visual acuity recovered to 6/9 to 6/7.5 (20/30 to 20/25), but vision was poor when illumination or contrast was low. In order to determine whether the decrement in visual performance was the result of misalignment of the photoreceptors, the subject's SCFs were determined 9 months postoperatively for both eyes, using a procedure similar to that used earlier. The relative luminous efficiency curves for both eyes were found to be surprisingly similar to the corresponding curves found 38 years earlier. It was concluded that any decrease in visual function resulting from the retinal detachment and repair was not caused by misalignment of the photoreceptors. We infer that the mechanisms resulting in the exceptionally high degree of photoreceptor alignment in the left eye and the disturbed alignment in the right eye are still present.

ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

There are many useful longitudinal and cross-sectional epidemiological studies of how visual acuity (VA) deteriorates with age. However, few studies have evaluated age-related VA changes in normal, healthy eyes. Data from three previous studies that included VA measurements taken with logMAR charts from subjects with normal, healthy eyes were collated and additional data from 42 subjects were added. This provided VA results from 223 subjects (age range 18 to 80 years). Mean logMAR VA improved from -0.13 (Snellen equivalent 6/4.5) in 18- to 24-year-olds to -0.16 (Snellen 6/4-1in 25- to 29-year-olds and then gradually became worse with age to a mean value of -0.02 (Snellen 6/6+1) for subjects over 75 years of age. The inadequacy of 6/6 as a norm value of VA is illustrated. The data show VA levels far superior to the data from the standard references of Pitts (1982) and Weale. (1975, 82) We suggest that this is because we used logMAR charts (providing nontruncated data), the subject's optimal refractive correction (rather than habitual) and strict exclusion criteria ensuring that only subjects with normal, healthy eyes were recruited for the studies.

ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Visual abilities decline during senescence. Age-related declines cannot be attributed entirely to changes in optical factors (senile miosis and opacification of the ocular media) and must therefore be caused by changes in the visual pathways. Because pattern visual evoked potentials (VEPs) provide information regarding the sensory function and integrity of the visual system, recent research on age-related changes in VEPs is reviewed. The results of this review show that stimulus parameters of VEPs (luminance, contrast, spatial and temporal frequencies) modify the age-related changes in VEPs. The visual system consists of multiple, parallel channels which process different information. Therefore, it is hypothesized that aging may affect the specific functional subdivisions in the visual pathways differentially.

ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Purpose.This study examined the temporal summation properties of the aging visual system under a wide range of background luminances.Methods.Contrast thresholds for 0.5 cpd gratings for 12 younger (mean age 20.6 years) and 12 older (mean age 71.6 years) observers in good ocular health were measured for 6 stimulus durations (from 10 to 1000 ms) under 4 background luminances (from 0.44 to 249.50 cd/m2). Two-alternative forced-choice staircase method was used.Results.We found significant main effects of age, background luminance, and stimulus duration on the contrast threshold. There were no age-related differences in the shape of the threshold- duration functions under all background luminances, although the shape changed significantly with background luminance. Age-related differences in contrast threshold were significant under the two lowest, but not under the two highest, background luminances.Conclusions.Age-related alteration in visual sensitivity may be attributed to sensitivity (amplitude) losses but not to changes in temporal characteristics of the visual system.

ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Purpose.To establish the effect of aging upon shortwavelength- sensitive cone (S-cone) sensitivity for both normals and patients with primary open-angle glaucoma (POAG).Methods.S-cone thresholds were established for the detection of blue test spots on a bright yellow adapting background. Detection thresholds for combined medium- and long-wavelengthsensitive cones (M/L-cones) were also established for a yellow test spot upon a yellow background. A group of 177 normal subjects (age range 20 to 80 years) and 46 glaucoma subjects were examined.Results.The rate of decline of S-cone sensitivity with increasing age was found to be similar in patients with POAG and age-matched normals (˜ 0.2 log units/decade), although S-cone sensitivity in the POAG population was significantly lower (p<0.05) than that in age-matched normals by ˜ 0.3 log units.Conclusions.The results of the present investigation show an age-related decline in S-cone sensitivity for both normals and patients with POAG. The decline in S-cone sensitivity within the POAG population is similar to that occurring in normal subjects when the two populations are matched for age.

ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Two models of performance in visual classification tasks, the fast-guess model and the accumulator model, offer contrasting accounts of the relation between speed and accuracy. We attempted to distinguish these models in the context of age-related changes in visual search performance. Twenty-four young adults (mean age 21.50 years) and 24 older adults (mean age 66.17 years) performed a visual search task requiring the detection of an upright L among rotated L's. The results supported the accumulator model, in that mean reaction time (RT) was higher for error responses than for correct responses, and there was a positive relation between RT and error rate. Both of these effects were more pronounced for older adults than for young adults, even when visual acuity was covaried statistically. We conclude that age-related changes in visual search performance involve a decline in the efficiency of sampling the amount of evidence necessary to exceed a decision criterion.

ISSN:1040-5488    

出版商:OVID    

年代:1995

数据来源: OVID