Abstract
Purpose :
To describe 20-year secular trends in visual impairment (VI) prevalence and its association with myopia in Chinese school children.
Methods :
For the first time ever, we used nationwide representative individual level data to investigate the myopia situation in China. Time series of five successive cross-sectional surveys conducted from 1995 to 2014. Participants included 1,085,003 children aged 7–18 years from all 26 provinces and four municipalities of mainland China, excluding Tibet. Unaided distance visual acuity (VA) for each eye was measured by certified optometrists using a retro-illuminated logarithm of minimum angel of resolution (LogMAR) chart with tumbling-E optotypes (Precision Vision, Denver Colorado). We followed the definitions for population surveys set by the International Council of Ophthalmology (ICO) in cooperation with the World Health Organization (WHO): mild VI being 6/7.5>unaided distance VA≥6/18, moderate and severe VI being unaided distance VA<6/18, and the presence of VI was defined as the unaided distance VA<6/7.5 in the worse eye. Myopia was diagnosed by noncyclplegic subjective refraction using spherical lenses.
Results :
Among students aged 7-18 years, the prevalence of total visual impairment increased from 35.1(95%CI: 34.9, 35.3) in 1995 to 55.0(95%CI: 54.8, 55.3) in 2014. The prevalence of mild VI increased from 14.3% in 1995 to 16.5% in 2014 (P trend test<0.001). The prevalence of moderate and severe VI increased from 20.8% in 1995 to 38.6% in 2014 (P trend test<0.001). In all survey years, VI prevalence tripled in the 16-18 age group compared to the 7-9 age group. Higher prevalence of visual impairment was found in girls (58.3% in 2014) and children living in urban areas (59.9% in 2014), although rural areas showed a more rapid increase in prevalence (28.3% in 1995 to 50.2% in 2014) than urban areas (41.7% in 1995 to 59.9% in 2014). The prevalence of myopia increased in all age groups over the two decades and increased as children got older. The prevalence of myopia highly correlated that of VI prevalence from 1995 to 2014 (total r=0.990, p<0.001; female r=0.990, p<0.001; male r=0.991, p<0.001; rural r=0.992, p<0.001; urban r=0.988, r<0.001).
Conclusions :
There has been a rapid but regionally variable rise in the prevalence of visual impairment associated with uncorrected myopia across China. Without further intervention, future exacerbation of the myopia crisis is extremely likely.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.