天津市视力残疾鉴定15834例分析

目的 调查“十一五”期间天津市进行视力残疾鉴定患者的基本情况、等级分布及主要致残原因,为日后低视力康复工作的开展提供有价值的资料.方法 调查研究.收集2006年1月至2010年12月天津市进行视力残鉴定并明确诊断的视残患者15834例.记录患者个人情况及眼部情况,根据第二次全国残疾人抽样调查视残废分级标准,对患者进行分级并明确致残原因.不同致残原因所致盲和低视力频数分布的差异进行x2检验.结果 男性视残患者多于女性,市区多于郊县,较高年龄、较低文化程度及低家庭经济收入者所占比例较大.15834名视残患者中盲6598例(41.67％),其中一级5015例(31.67％),二级1583例(10.00％);低视力9236例(58.33％),其中三级1713例(10.82％),四级7523例(47.51％).白内障5196例(32.82％),其中盲32.98％,低视力32.70％.除白内障外,盲与低视力主要致病原因的构成不完全相同(x2=38.33,P＜0.01).致盲病因主要为视网膜/葡萄膜病变(15.40％)、角膜病(13.78％),而致低视力病因主要为屈光不正/弱视(18.32％)、视网膜/葡萄膜病变(17.37％).结论 天津市“十一五”期间确定的视残者中低视力患者多于盲患者,白内障仍是首要致残原因.     

BD8 certification of visually impaired people

BACKGROUND—There is debate as to the completeness of the blind and partial sight registers in England and Wales. The purpose of this study was to estimate the proportion of eligible visually impaired people attending the hospital eye service who have a BD8 certificate and to identify factors associated with not being certified.
METHODS—Cross sectional survey of patients attending outpatients by medical record review analysed by multiple logistic regression.
RESULTS—51% (43%, 58%) of patients identified as eligible for registration did not have a BD8 certificate. The severity of visual impairment and the main diagnosis in terms of requirements for treatment, permanence of visual loss, and visual field loss were independently associated with non-certification. A partially sighted patient is estimated to be three times more likely to not have a BD8 certificate as a blind patient of similar diagnosis (adj OR: 3.4 (95% CI: 1.7, 6.8)). A patient whose impairment is due to abnormal visual fields is estimated to be greater than three times more likely to be non-certified than one with low visual acuity of similar severity and cause (adj OR: 3.6 (95% CI: 1.0, 12.7)). People whose impairment is potentially reversible are estimated to be eight times ( 8.3 (2.2, 31.4)) more likely not to have a certificate compared with people who had permanent non-treatable visual loss; and in those with permanent visual loss, a requirement for ongoing treatment was found to be associated with a lower odds of certification.
CONCLUSIONS—These data strongly suggest that epidemiological data collected during registration are biased towards permanent, non-treatable causes of visual loss and those which affect central rather than peripheral vision. Certain subgroups of the visually impaired are likely to be at greater risk of non-certification. BD8 guidelines need to be simplified.

Keywords: registration; BD8 certification; data collection; visual impairment     

Intensity and structure of visually evoked neural activity: Rivals in modelling a visual system

Extracellular recordings have been made from the directionally selective movement detectors in the lobula complex of the blowfly. The intensity aspect of the spike activity—represented by the mean interspike interval—as well as the temporal structure aspect of the activity—represented by the interval distribution function and the correlation of adjacent intervals—are studied. Steady state stimuli appear to have no influence on the temporal structure of the spike activity: the stimulus tunes the firing frequency into a certain level, leaving the temporal structure—but for a change in mean interspike interval—unaffected. Dynamic stimuli, however, affect—besides their modulating influence on the spike activity—both aspects. The magnitude of the change in temporal structure is related to the excitatory resp. inhibitory character of the stimulus presented in the visual field of the detector. From the results presented, it follows that besides the intensity aspect of the spike activity, the structural aspect as well yields evident clues in modelling a visual system.     

Mobile assistive technologies for the visually impaired

There are around 285 million visually impaired people worldwide, and around 370,000 people are registered as blind or partially sighted in the UK. Ongoing advances in information technology (IT) are increasing the scope for IT-based mobile assistive technologies to facilitate the independence, safety, and improved quality of life of the visually impaired. Research is being directed at making mobile phones and other handheld devices accessible via our haptic (touch) and audio sensory channels. We review research and innovation within the field of mobile assistive technology for the visually impaired and, in so doing, highlight the need for successful collaboration between clinical expertise, computer science, and domain users to realize fully the potential benefits of such technologies. We initially reflect on research that has been conducted to make mobile phones more accessible to people with vision loss. We then discuss innovative assistive applications designed for the visually impaired that are either delivered via mainstream devices and can be used while in motion (e.g., mobile phones) or are embedded within an environment that may be in motion (e.g., public transport) or within which the user may be in motion (e.g., smart homes).     

Needs analysis for teachers of the visually impaired

The needs of educators dealing with low vision children were assessed by use of a mailed questionnaire. Teachers of the visually impaired (VH) of the Los Angeles City, Los Angeles County, and Long Beach City districts comprised the sample population. Analysis of the results revealed unmet needs in the following areas: teachers' knowledge in use of low vision aids, lack of low vision assessment by vision care specialists for their students, difficulty with adequacy of eye reports, and lack of communication with their students' eye care specialists. Recommendations are made for improvement of these problem areas.     

The development of the LV Prasad-Functional Vision Questionnaire: a measure of functional vision performance of visually impaired children

PURPOSE: To develop a reliable and valid questionnaire (the LV Prasad-Functional Vision Questionnaire, LVP-FVQ) to assess self-reported functional vision problems of visually impaired school children. METHODS: The LVP-FVQ consisting of 19 items was administered verbally to 78 visually impaired Indian school children aged 8 to 18 years. Responses for each item were rated on a 5-point scale. A Rasch analysis of the ordinal difficulty ratings was used to estimate interval measures of perceived visual ability for functional vision performance. RESULTS: Content validity of the LVP-FVQ was shown by the good separation index (3.75) and high reliability scores (0.93) for the item parameters. Construct validity was shown with good model fit statistics. Criterion validity of the LVP-FVQ was shown by good discrimination among subjects who answered "seeing much worse" versus "as well as"; "seeing much worse" versus "as well as/a little worse" and "seeing much worse" versus "a little worse," compared with their normal-sighted friends. The task that required the least visual ability was "walking alone in the corridor at school"; the task that required the most was "reading a textbook at arm's length." The estimated person measures of visual ability were linear with logarithm of the minimum angle of resolution (logMAR) acuity and the binocular high contrast distance visual acuity accounted for 32.6% of the variability in the person measure. CONCLUSIONS: The LVP-FVQ is a reliable, valid, and simple questionnaire that can be used to measure functional vision in visually impaired children in developing countries such as India.     

Lesions of the lacrimal drainage system: a clinicopathological study of 643 biopsy specimens of the lacrimal drainage system in Denmark 1910-1999

PURPOSE: To determine the frequency of histologically verified lesions of the lacrimal drainage system in Denmark between the years 1910 and 1999. Furthermore, to correlate the clinical diagnosis with the pathology diagnosis. METHODS: Retrospective review of all pathology reports from 1910 to 1999 in the files of the Eye Pathology Institute, University of Copenhagen, describing a lesion of the lacrimal drainage system. In addition, a retrospective review of all reports describing a lesion of the lacrimal drainage system from the Danish Pathology Database. All specimens were re-evaluated, except in cases with a primary diagnosis of dacryocystitis. In these cases a sample of 25% was re-evaluated. RESULTS: A total of 643 lesions were collected. Dacryocystitis was the most frequent lesion, constituting 508 cases (79%). The remaining cases were diagnosed as dacryolithiasis (62 cases; 7.9%), tumour (29 cases; 4.5%), trauma (19 cases; 3.0%), congenital malformation (nine cases; 1.4%), canaliculitis (eight cases; 1.2%) and granulomatous inflammation (eight cases; 1.2%). Seventeen tumours were malignant, of which B-cell lymphoma was the most common (six cases). In 0.6% of cases with a clinical diagnosis of dacryocystitis/lithiasis a non-suspected malignant tumour was diagnosed. Micro-organisms were uncommon in dacryocystitis (9%) but frequent in cases of dacryolithiasis (87%). CONCLUSION: Dacryocystitis was by far the most frequent lesion of the lacrimal drainage system referred for histopathological evaluation. Dacryolithiasis was often associated with micro-organisms, especially Gram positive rods. Histopathology is necessary to confirm suspected tumours, more than half of which were inflammatory lesions, and to detect tumours that sometimes masquerade as inflammation.     

Limitations of image enhancement for the visually impaired.

Image enhancement as an aid for the visually impaired may improve visibility of TV programs and provide portable visual aid. This paper describes the current techniques for image enhancement and their underlying models. The limitations of the various techniques and of potential methods of implementation are high-lighted. Initial work in this area was based on a linear model. The finite dynamic range available in the video display and contamination of the enhanced image by high spatial frequency noise limited the model's usefulness. I propose a method to address some limitations of the original model that considers the nonlinear response of the visual system and requires enhancement of subthreshold spatial information only. This modification may increase the dynamic range available by decreasing the range previously used by the linear models to enhance visible details. However, for the modified technique to be most effective, the enhancement has to be continuously tuned, based on the patient's visual loss and the spatial frequency content of the displayed images. The implications of these limitations for the potential implementation in TV are discussed. Implementation of an image-enhancing visual aid in a head-mounted, binocular, full-field, virtual vision device may cause substantial difficulties. Patient adaptation may be difficult due to head movement and interaction of the vestibular system response with the head-mounted display. An alternate, bioptic design is proposed in which the display is positioned above or below the line of sight to be examined intermittently, possibly in a freeze-frame mode. Such implementation is also likely to be less expensive, enabling more users access to the device.