[A cross-sectional study on the prevalence of visual impairment in 2006 in Hubei province, China].

OBJECTIVE: To determine and compare the prevalence and causes of visual disability in urban and rural areas of Hubei province. METHODS: A cross-sectional study. From April 1 to May 31 in 2006, based on a stratified, multi-stage, cluster-sampling strategy, 31 counties (cities, districts), 124 townships (towns, streets), altogether 248 investigation districts, 101 674 sample individuals from Hubei province were selected to conduct inquiry registration, screening and visual disability evaluation. The revised 'Criteria of Disability' formulated by the specialist committee of the 2nd National Sample Survey of Disability was applied. The diagnosis and grading of visual disability were based on history of illness and vision function examination. The etiology diagnosis was made according to the causes of disability and the causing diseases. Chi-square test was used to investigate differences due to gender, age, and areas (urban and rural). RESULTS: The overall prevalence rate of visual disability in Hubei province is 1.40% (95%CI: 1.33% - 1.47%). The rate is 0.93% (95%CI: 0.88% - 0.98%) for urban areas and 1.62% (95%CI: 1.24% - 2.00%) for rural areas. Rural areas have a higher rate than urban ones and the difference is statistically significant (chi(2) = 68.2410, P < 0.0001). The rate increases with age in both urban and rural areas. In age groups older than 10, the prevalence rate in rural areas is higher than urban areas, and the difference becomes significant (chi(2) = 33.6569, P < 0.0001) for age groups 30-80. Females have a higher rate (1.63%) than males (1.18%) (chi(2) = 37.8386, P < 0.0001). The main eye diseases causing visual disability in urban areas are cataract (53.77%), retinopathy and choroidopathy (10.82%), ametropia (7.87%), glaucoma (6.23%) and hereditary/congenital diseases and developmental disorders (5.90%). The main causing diseases in rural areas are cataract (48.61%), corneal diseases (14.17%), glaucoma (6.91%), retinopathy and choroidopathy (6.19%) and hereditary/congenital diseases and developmental disorders (5.20%). CONCLUSIONS: The rural areas have a higher prevalence rate of visual disability than urban areas in Hubei province. Cataract is the leading cause of visual disability. We should continue the work of prevention and cure of visual disability, the primary work being cataract surgery. More stress should be placed on the prevention and cure effort in rural areas and for females and elderly people.

Determination of median nerve somatosensory evoked potentials in 27 patients with hemiplegia.

Twenty-seven in-patients with hemiplegia following brain injury were studied by using upper extremity median nerve somatosensory evoked patentials (SVEP), Brunnstrom assessment in hemiplegic hand and assessment of the patients' activities of daily lioing (ADL) (Barthel index). The upper extremity median nerve SEP on the affected and normal sides was determined. By using Kovindha standard, upper extremity median nerve SEP was graded in accordance with N20. The correlation between the differences of SEP N20 amplitude and the latencies on the both sides and the Barthel index scores was analyzed. A Spearman correlation analysis was made between the median nerve SEP N20 grades and Brunnstrom stages in hand or ADL on the affected side. The results showed that upper extremity median nerve SEP grades were positively correlated with those of the Brunnstrom stages in hand (r1 = 0.6925, P1 < 0.01). The correlation coefficient between SEP N20 grades and patients' ADL grades was r2 = 0.5015, P2 < 0.01. It was concluded that upper extremity median nerve SEP could be used as a sensitive electrophysiological predictor to clinically assess hemiplegic hand function. SEP N20 might play a role in predicting the ADL of the patients with hemiplegia to some extent, but could not be used as a sensitive predictor to directly observe and predict the ADL of the patients.