Abstract
Purpose:
Close work is an important and major part of people’s daily activity, thus quality of life would be limited once near vision impairment (NVI) occurs. However little is known about the incidence of NVI or its risk factors by far. We conducted a population-based longitudinal study to investigate the 2-year incidence of NVI and related risk factors in an adult Chinese population.
Methods:
Participants aged 35 years or older were recruited using cluster random sampling from Yuexiu District, Guangzhou, China in 2008. The mean age of the 1817 (79.6% of the eligible) participants was 53.3±13.0 years. All participants were invited for the 2-year follow-up and both visits included binocular near visual acuity (NVA) measurement and noncycloplegic auto refraction test along with a brief questionnaire. NVA was measured at 40cm using a logMAR near vision tumbling E chart. Subjects with uncorrected binocular NVA≤20/40 were corrected to obtain best-corrected NVA. Logistic regression analysis was used to assess the relationship of age, gender, education level, baseline uncorrected NVA and spherical equivalence (SE) with the incidence of NVI.
Results:
Data were available for 1595 (88.7%) of 1798 survivors (99.0%) in the follow-up. The mean age was 55.2±12.5 years, of whom 54.8% were female. Participants did or did not return for the follow-up didn’t differ in age, sex or education level at baseline. The 2-year incidence of binocular uncorrected NVI (uncorrected NVA≤20/40, UCNVI) and best-corrected NVI (best-corrected NVA≤20/40, BCNVI) were 23.7% (95% confidence interval [CI] 20.4-27.2%) and 3.5% (95%CI 2.6-4.5%), respectively. Logistic regression analysis showed that older age (OR=1.15, P<0.001) and worse baseline uncorrected NVA (OR=11.91, P=0.024) were significantly associated with higher incidence. After adjusting for age and baseline corrected NVA, female gender (OR=1.58, P=0.035), but not education level or SE was associated with higher incidence of UCNVI. Likewise, more myopic RE (OR=1.20, P=0.002) and lower education level (OR=1.61, P=0.001) was associated with higher incidence of BCNVI.
Conclusions:
The 2-year incidence of NVI is high in this population and people with older age or worse baseline NVA are at higher risk of developing NVI. Longer time follow-ups are needed to learn more about the incidence of NVI and related risk factors for preventive strategies.