Refractive errors in an elderly Chinese population in Taiwan: the Shihpai Eye Study.
OBJECTIVE
Few epidemiologic data are available on refractive status in elderly Asians. The purpose of the study was to determine prevalence and risk factors associated with refractive errors in a metropolitan elderly Chinese population in Taiwan.


METHODS
A population-based survey was conducted in the Shihpai district of Taipei, Taiwan. A total of 2045 residents aged 65 years or more were randomly selected and invited to complete a comprehensive questionnaire and undertake a detailed ocular examination, including best corrected visual acuity and measurements of refractive error, using autorefraction. Of the subjects, 1361 (66.6%) participated in the ocular examination. Spherical equivalent (SE) was calculated in diopters (D), and data from right eyes were reported.


RESULTS
The age- and sex-adjusted prevalence rates were determined for myopia (SE<-0.5 D, 19.4%; SE<-1.0 D, 14.5%), high myopia (SE<-6.0 D, 2.4%), hyperopia (SE>+0.5 D, 59.0%; SE>+1.0 D, 44.2%), astigmatism (cylinder<-0.5 D, 74.0%; cylinder<-1.0 D, 45.3%), and anisometropia (SE difference between right and left eyes>0.5 D, 45.2%; SE difference>1.0 D, 21.8%). The prevalence of myopia, astigmatism, and anisometropia significantly increased with age (all P<0.01). The prevalence of hyperopia tended to decrease with age. There was no gender difference in prevalence rates in any type of refractive error, except that women had a higher rate of hyperopia (SE>+1.0 D) than men (P=0.004). Multivariate regression analysis showed that myopia was weakly associated with higher educational level. The severity of lens nuclear opacity was positively associated with the rates of myopia and negatively associated with the rates of hyperopia.


CONCLUSIONS
The prevalence of myopia in this elderly Chinese population is not much higher than in similarly aged elderly white populations, compared with a much greater difference in prevalence among younger Chinese versus white people. This suggests that changing environmental factors may account for the increased prevalence of myopia in younger cohorts of Chinese.
Department of Ophthalmology, School of Medicine, Institute of Clinical Medicine, National Yang Ming University, Taipei, Taiwan. cycheng@ms16.hinet.net
Ching-Yu
CY
Cheng
Wen-Ming
WM
Hsu
Jorn-Hon
JH
Liu
Su-Ying
SY
Tsai
Pesus
P
Chou
D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000208:ethnology; D005260:Female; D015577:Geriatric Assessment; D006299:Health Services for the Aged; D006306:Health Surveys; D006801:Humans; D008297:Male; D015995:Prevalence; D012030:Refractive Errors / Q000208:ethnology*; D017678:Sex Distribution; D011795:Surveys and Questionnaires; D013624:Taiwan / Q000453:epidemiology