摘要:

Background.Previous studies that have attempted to determine the effect of orientation and mobility training on mobility performance of visually impaired adults have had a number of limitations. With the inclusion of a control group of subjects, this study investigated the effect of orientation and mobility training on mobility performance of a group of visually impaired adults.Methods.Vision was measured binocularly as high- and low-contrast visual acuity, letter and edge contrast sensitivity, and Humphrey kinetic visual fields. The subjects’ mobility performance was assessed as percentage preferred walking speed (PPWS) and error score before and after mobility training.Results.Orientation and mobility training did not enhance mobility performance compared with the control group, who did not receive training, when performance was measured immediately after training. PPWS improved for both groups with short-term practice only, but there was no improvement in error score due to either practice or training.Conclusions.There was no immediate improvement in mobility performance of visually impaired adults after orientation and mobility training. Familiarity with the route may play an important role in measured improvement of mobility performance after orientation and mobility training.

ISSN:1040-5488    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.The purpose of this study was to determine whether persons with advanced vision impairment, when walking an unfamiliar route, visually sample the environment in a different manner than do persons with normal vision.Methods.Direction of gaze was measured in six persons with retinitis pigmentosa (RP) and in three persons with normal vision as they walked an unfamiliar, obstacle-free route while viewing the environment in a head-mounted display.Results.Persons with RP fixated over a larger area in the environment and at different features than did persons with normal vision. Persons with normal vision directed their gaze primarily ahead or at the goal, whereas persons with RP directed their gaze at objects on the walls, downward, or at the layout (i.e., edge-lines or boundaries between walls). The results also showed a significant negative correlation between the horizontal visual field extent of the RP subjects and the proportion of downward-directed fixations.Conclusions.Persons with advanced vision impairment as a result of RP visually sample the environment in a manner different from persons with normal vision.

ISSN:1040-5488    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.Most previous studies have shown static vernier acuity for high-contrast targets to be largely unaffected by aging; those examining adult age differences on oscillatory displacement thresholds have consistently reported marked age deficits. The goals of this study were to (1) measure the age deficit on oscillatory discrimination beyond that attributable to any change in spatial discrimination by using the same target configuration for both task types and (2) determine whether an age-related change in the contrast response of the visual system contributes to age differences on static or oscillatory discrimination.Methods.The displacement thresholds of young and old observers for a vernier task configuration were determined at two target contrast levels (0.08 and 0.64) for static and oscillating targets (2 and 6 Hz)Results.No age differences were seen on static displacement thresholds at either high or low contrast. A marked age deficit that emerged when oscillation was increased was unrelated to target contrast or observer contrast sensitivity.Conclusions.Age-related declines in oscillatory discrimination beyond those attributable to spatial discrimination do not appear to be attributable to optical factors nor to a decline in the contrast response of the senescent visual system. These findings are discussed in terms of a functional decline in the magnocellular pathway, or “neural entropy,” possibly due to random cell loss.

ISSN:1040-5488    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.A recent study indicated that patients with cataracts and early age-related maculopathy may benefit from cataract extraction. To ascertain whether cataract extraction in the presence of concurrent advanced age-related maculopathy was also associated with a clear benefit, we studied visual function and self-reported visual functioning in a cohort of 12 patients pre- and post-phakoemulsification.Methods.All 12 patients had a diagnosis of advanced age-related maculopathy in the eye scheduled for cataract surgery. Preoperative assessment included refraction and recording of best corrected distance and near acuity and contrast sensitivity in both eyes. The Daily Living Tasks Dependent on Vision questionnaire was administered. After phakoemulsification and intraocular lens implantation, all patients were reviewed and assessed.Results.After surgery, improvement in acuity was recorded in nine operated eyes, whereas acuity remained unchanged in three eyes. Improvement in contrast sensitivity in the operated eye occurred in 10 patients, but in two patients contrast was reduced postoperatively. In terms of self-reported visual functioning, improvement in the ability to undertake many daily living tasks dependent on vision was recorded after cataract surgery.Conclusions.Significant improvements in specific areas of self-reported visual functioning and measures of vision were recorded after cataract surgery. During the follow-up period, none of the operated eyes suffered a fall in visual acuity. There was also no evidence of worsening of the pre-existing macular lesion as judged by clinical examination and fundus photography.

ISSN:1040-5488    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2001

数据来源: OVID