AIM: To compare the optometric examination results of myopic young children between those diagnosed in the period from 1998 to 2000 and those diagnosed in the period from 2008 to 2010; and to find out the causes of myopia and factors that worsen the condition, and suggest methods of its prevention and treatment.

METHODS: This study was a retrospective case study. We randomly selected sample from out-patient department register of cases and divided them into two main groups, ‘ten year before group'(TYBG)(1998/2000 year cases)and ‘ten years later group'(2008/2010 year cases)(TYLG). Each group was further subdivided into three sub-groups by age: under-six years old children group(CG), seven-twelve years old primary-school group(PSG)and thirteen-eighteen years old middle-school group(MSG). The optometric examination results were statistically analyzed.

RESULTS: The difference of the mean dioptre between the TYBG and TYLG was strongly statistically significant, also forward-lead trend of age when children suffered from myopia was found(P<0.01). There was a significant increase of dioptre among PSG and MSG in TYLG compared to TYBG(P<0.01). After analyzing the relationship between dioptre and age, this study showed an increase of the proportion of myopia patients from 35.2% to 50.0% in PSG in ten years interval. This proportion decreases in MSG and remains stable in CG. All cases had been divided into slight myopia, medium myopia and high myopia, depending on their own myopia dioptre. The biggest difference of myopia dioptre were seen in MSG where the proportion of medium myopia patients increased 11.4% and high myopia patients increased 7.9% in TYLG.

CONCLUSION: Our study shows that the age of getting myopia was forward lead, the dioptre increases by 1.00 degree and the prevalence of myopia is increasing gradually. This situation may due to the modern life style and changes of living standard of the population. Therefore, prevention of myopia should concentrate more on younger children at kindergarten and primary school stage students.