[Problems in planning and conducting an ophthalmic population-based epidemiology survey].

Nowadays, the number of ophthalmic population-based epidemiology survey is increasing in China But some distinct shortcomings of the planning and conducting steps, such as wrong concept of the relationship between statistic correlation and risk factor, unnecessary large sample size, inappropriate sampling method, informal design of questionnaire, no pilot study, improper field study, incorrect data input and sort, no quality control, etc., are presented in some surveys, resulting in the poor reliability. Valuable epidemiology results could be obtained only after elucidation of these problems and using a standard design.