EARLY SIGNS OF MYOPIA IN CHINESE SCHOOLCHILDREN

We looked for the earliest signs of the onset of myopia in 194 emmetropic (-0.25 to +0.75 D) eyes by following them for 1 to more than 2 years. Visual acuity examination, cycloplegic retinoscopy, and A-scan ultrasonography were performed at intervals of 6 to 12 months. Of the 194 eyes 64 became myopic during the observation time. Our results show that during the progression from emmetropia to myopia the change in visual acuity is not a good indicator of the onset of myopia. When visual acuity decreased to below 6/6 (20/20) cycloplegic retinoscopy showed that most of the 64 eyes had become truly myopic and A-scan ultrasonography revealed a significant increase in vitreous chamber depth and axial length as compared to the non-myopic eyes. in the early stage of myopia development the anteroposterior diameter of the eye elongates: However, changes in anterior chamber depth and lens thickness did not differ between the myopic and non-myopic group. Our results suggest that routine ocular refraction should be conducted in addition to the school vision screening. For those who have visual acuity 6/6 (20/20) and ametropia of -0.25 D or more minus we would like to be able to prevent or at least retard the development of myopia.