Abstract
Purpose :
To evaluate the pattern of age of onset of high myopia (HM) and associated factors in myopic Singapore children.
Methods :
In the Singapore Cohort of the Risk factors for Myopia (SCORM), school children aged 7 to 9 years were followed up till 16 years of age. HM was defined as spherical equivalent (SE) of ≤ -5.0D in the worst eye and age of onset of HM determined at yearly eye examinations whereby cycloplegic refraction and axial length measures were performed. Elapsed time of progress from myopia to HM was calculated as age of onset of HM minus age of onset of myopia. Questionnaires were used to assess nearwork, outdoor time and family history. Multivariable adjusted Cox regression models were used to identify factors associated with age of onset of HM and time from myopia to HM.
Results :
Of the 1979 children, 1049 (53.0%) had myopia at the first visit, and 297 (15.0%) more developed HM by the last visit. The mean age (SD) of onset of myopia and HM were 8.1 (1.5) and 11.0 (2.1) years old, respectively. The mean elapsed time from myopia to HM was 4.4 (1.8) years. In a Cox regression model, earlier onset of myopia (hazard ratio [HR] 0.52, p<0.001), less time outdoors (HR 0.89, p < 0.003), and more books read per week (HR 1.05, p<0.004) were associated with earlier age of onset of HM (shorter time from birth to HM). Cox regression analysis revealed that Chinese ethnicity (p<0.001), earlier onset of myopia (p<0.001), less time outdoors (p=0.002), more books per week (p=0.03), and parental myopia (p=0.02) were associated with shorter time from myopia to HM.
Conclusions :
In Singapore children, mean age of onset of HM is 11 years and mean age of onset of myopia is 8.1 years. Age of onset of myopia, nearwork and time spent outdoors influence age of onset of HM, as well as the time from myopia to HM. Preventive efforts should be targeted at delaying age of onset of high myopia by increasing time outdoors in young children.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.