| Background Nowadays, blindness and vision impairment affect people’s quality of life and health seriously, and have been a public health and social issue which causes worldwide concern. There are three hundred and fourteen million people with vision impairment in the world, including45million cases for blindness. In China, the prevalence of blindness is between0.5%and0.6%, or7million cases, in which the prevalence of low vision for both eyes is0.99%, or12million cases. Currently, whether in China or in the world, cataract is still the first cause for vision loss and vision impairment. There are more than20million people with vision loss caused by cataract. The prevalence of cataract is about20%among farmers aged50years and above all over the country and there are about two million and nine hundred ten thousand people with vision loss caused by cataract. The blindness and vision impairment caused by cataract have seriously affected the people’s quality of life, and the need for an increasing cataract extraction with intraocular lens implantation has been one of the most expensive method for the public health.In1999, World Health Orgnization (WHO) and some Non-governmental Orgnization co-founded "vision2020" plan, which aims to strengthen co-operation all over the world to eliminate the avoidable blindness caused by cataract, trachoma, childhood blindness, low vision, ametropia and so on. Chinese government also eagerly responded to this summon and made a commitment. Various level of prevention and care blindness institutions have been founded by the end of1980s in Shandong province and a large scale of epidemiological survey was performed for blindness and low vision. Further, the plan for prevention and care blindness was well laid out. However, after more than20years’ development, the population and socio-economic conditions have been markedly changed. To efficiently implement the goal, lay out further guidelines and promote the development of prevention and therapy of blindness, it is necessary to reevaluate the prevalence of blindness and vision impairment. Hence, the present study will provide epidemiological data and policy basis for the prevention and therapy of blindness in Juancheng county.Objective A prevalence survey on the incidence, reasons of blindness and vision impairment, prevalence of cataract and cataract-caused risk factors as well as suigical coverage rate of cataract was carried out among farmers aged50years and above in Juancheng County, Shandong province. Furthermore, the related status of blindness and vision impairment was also investigated for the purpose of providing policy basis and epidemiological data in prevention and therapy of blindness and vision impairment in large populations.Methods During April and July in2008, a random cluster sampling was applied to select rural residents in Juancheng County. Four thousand eight hundred sixty six individuals were randomly selected to investigate vision, and examination of eyes was performed in the population aged50years and above. Visual acuity was performed according to the logarithm visual chart and the incidence of blindness, moderate and severe vision impairment was measured based on the new criteria of blindness and vision impairment made by World Health Organization in2009; meanwhile, the main reason analysis for eyes with vision impairment was also performed. The risk factors for cataract formation were evaluated by non-conditional Logistic regression according to cataract incidence and surgical coverage rates. A preliminary test was carried out prior to the normal field investigation, and repetitive test was also done to assure the quality of the field investigation. Furthermore, the relevant quality control was strictly followed for whole investigation to guarantee the credibility before, during and after the field investigation.Results Five thousand and two hundred eighty seven individuals aged50years and above were enumerated. Actual figures for examination were4866and the response rate was92.04%.1. Of all actual survey individuals, there were1108cases with blindness, moderate and severe vision impairment and the prevalence was22.77%. In which,86persons developed blindness for both eyes and the prevalence was1.77%; there were100persons with blindness for single eye and the disease rate was5.14%;314cases developed moderate or severe vision impairment (prevalence,6.45%);458cases were subjected to single eye vision impairment with moderate or severe degree (prevalence,9.41%); the prevalence was25.42%for female and19.21%for male, the prevalence for female was higher than that for male;Furthermore, the prevalence was gradually increased with the increase of age and the prevalence was10.08%for individuals aged50years and above,23.57%for individuals aged60years and above,50.08%for individuals aged70years and above,67.61%for individuals aged80years and above. There were significant differences among all age groups. The prevalence in healthy group based on self-assessment was21.75%and was30.20%in normal group, the prevalence in healthy group is lower than in normal group; the prevalence was21.62%in group without systemic disease whereas29.32%in group with systemic disease, and the prevalence in group with systemic diseases was higher than in group without disease; the prevalence for persons with illiteracy was24.30%and was10.83%for ones with literacy, and the prevalence in the former was higher than in the latter. The prevalence for persons with an average annual income less than1000yuan, more than1000yuan, more than 2000yuan and more than3000yuan was18.51%、25.08%、19.94%、18.64%, respectively, and an significant difference was observed for each annual income persons. Taken together, the prevalence of blindness and vision impairment was related to gender, age, education level, physical condition, healthy status and economic situation.2. The top five leading to blindness and moderate, severe vision impairment were cataract(41.97), ametropia(26.76%), macular degeneration(13.46%), optic atrophy(3.42%),amblyopia(3.40%) and corneal opacity/scar(3.40%), respectively. Cataract is still the first disease which leads to blindness and vision impairment.3. The cataract prevalence was39.8%for the individuals aged50years and above, in which the prevalence was37.1%for male and41.8%for female, the disease rate for the former was higher than that for the latter, and there existed significant difference between two groups; in the meantime, the cataract prevalence was13.6%for the crowd aged50years and above,49.6%for the crowd aged60years and above,87.2%for the crowd aged70years and above,94.4%for the crowd aged80years and above, respectively. With the increment of age, the cataract prevalence was apparently increased and there was marked difference among all age groups. The prevalence in healthy group based on self-assessment was37.8%and54.6%in normal group, the prevalence in normal group is higher than in healthy group and there existed significant difference; the prevalence was55.5%in group with systemic disease whereas37.0%in group without systemic disease, and there was significant difference; the prevalence for persons with illiteracy was41.7%and25.3%for ones with literacy, and the prevalence for the former was higher than that for the latter and there existed significant difference. Meanwhile, the prevalence in persons with an average annual income less than1000yuan, more than1000yuan, more than2000yuan and more than3000yuan was30.2%、44.1%、36.5%、32.7%, respectively, and an significant difference was obtained for each annual income group. The result of multivariate logistic regression analyses indicated that gender, age, education level and economic income were the main reasons for cataract formation.4. There were856people with the blindness or moderate, severe vision impairment, the cataract suigical coverage rate was17.59%. In which81persons developed both eyes blindness induced by cataract, and the suigical coverage rate was1.66%;203persons with single eye blindness and the suigical coverage rate was4.17%;250persons with moderate or severe vision impairment for both eyes and suigical coverage rate was5.14%;322persons with moderate or severe vision impairment for single eye and the suigical coverage rate was6.62%; The cataract suigical coverage rate was19.47%for female and15.07%for male, and the suigical coverage rate for female was higher than that for male. The cataract suigical coverage rate was increased with the increment of age, and the cataract suigical coverage rate was4.10%for the people aged50years and above,18.36%for the people aged60years and above,47.02%for the people aged70years and above,64.79%for the people aged80years and above, respectively. There existed marked difference among all groups. The suigical coverage rate in healthy group based on self-assessment was16.5%and25.6%in normal group, the suigical coverage rate in normal group was higher than in healthy group and there existed significant difference; meanwhile, the surgical coverage rate of cataract without systemic disease was16.25%and25.31%for the cataract patients with systemic disease, and there existed statisical difference, the surgical coverage rate for the former was lower than that for the latter. The suigical coverage rate for persons with illiteracy was18.92%and7.22%for persons with literacy, and the operation rate for the former was higher than that for the latter and there existed significant difference. Meanwhile, the suigical coverage rate for persons with an average annual income less than1000yuan, more than1000yuan and more than2000yuan was12.3%,20.0%,15.0%, respectively, and an significant difference was found for each annual income group. The result of one-factor analysis indicated that gender, age, education level, physical condition, healthy status and economic situation, were the main reasons for cataract suigical coverage rate.Conclusions1. The prevalence of blindness and moderate, severe vision impairment was22.77%among farmers aged50years and above in Juancheng County. In which, the prevalence of blindness with both eyes was1.77%and the prevalence of blindness with single eye was5.14%. The prevalence of vision impairment with both eyes was6.45%, and the prevalence of moderate, severe vision impairment with single eye was9.41%; Taken together, the prevalence of blindness and vision impairment was related to gender, age, education level, physical condition, healthy status and economic situation.2. The top five leading to blindness and moderate, severe vision impairment were cataract (41.97), ametropia (26.76%), macular degeneration (13.46%), optic atrophy (3.42%), amblyopia (3.40%) and corneal opacity/scar (3.40%), respectively. Cataract is still the first disease which leads to blindness and vision impairment.3. The prevalence of cataract was39.8%among farmers aged50years and above in Juancheng County. The prevalence of cataract was related to gender, age, education level and economic income status. Taken together, the prevalence of cataract for female was higher than that for male, and the older for the age, the higher for the cataract prevalence; the lower for the education level, the higher for the cataract prevalence; the lower for the annual economic income, the higher for the cataract prevalence.4. The suigical coverage rate was17.59%for the farmers aged50years and above in Juancheng County. In which the suigical coverage rate for both eyes blindness was1.66%, the rate of single eye blindness was4.17%and the rate of both eyes with moderate or severe vision impairment was23.00%and rate of single eye with moderate or severe vision impairment was12.68%, respectively. Gender, age, education level, physical condition, healthy status and economic situation. were the main influencing factors for cataract suigical coverage rate.5. Blindness and vision impairment are still serious problems in Juancheng County, and cataract is a key task in prevention and therapy of blindness from now on. For further preparation of prevention and therapy of blindness, it is advised that relevant measures should be taken in elevating surgical rate, getting the support from provincial items, asking for help of technological help from provincial hospitals, raising awareness of prevention and therapy of blindness, caring disadvantaged mass, uniting social strength and so on. |
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