Six-year changes in refraction and related ocular biometric factors in an adult Chinese population

• Published in: PloS one 2017-08, Vol.12 (8), p.e0183364-e0183364
• Main Authors: Han, Xiaotong, Guo, Xinxing, Lee, Pei Ying, Morgan, Ian G, He, Mingguang
• Format: Article
• Language: English
• Subjects: Acuity; Adult; Adults; Age; Aged; Aging; Analysis; Anterior chamber; Asian Americans; Asian People; Astigmatism; Astigmatism - diagnosis; Astigmatism - ethnology; Astigmatism - physiopathology; Biology and Life Sciences; Biometrics; Biometry; Biometry - methods; Cataracts; China; Cohort analysis; Confidence intervals; Cornea; Cornea - physiology; Cornea - physiopathology; Cylinders; Epidemiology; Female; Follow-Up Studies; Geriatrics; Humans; Interferometry; Laboratories; Laser interferometry; Linear Models; Longitudinal Studies; Male; Medicine and Health Sciences; Middle Aged; Myopia - diagnosis; Myopia - ethnology; Myopia - physiopathology; Older people; People and Places; Population; Population studies; Population Surveillance - methods; Prospective Studies; Refraction; Refraction, Ocular - physiology; Refractive errors; Research and Analysis Methods; Studies; Surgery; Surveys and Questionnaires; Time Factors; Vision Tests - methods; Vision Tests - statistics & numerical data; Visual acuity; Visual Acuity - physiology; Visual impairment; Visual perception
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0183364

To investigate longitudinal changes in refraction and biometry in Chinese adults. Population-based prospective cohort study. 1817 subjects aged ≥ 35 years were randomly recruited from Yuexiu district, Guangzhou, China in 2008. Of which 1595 (87.8%) were reexamined in 2010 and 1427 (78.5%) were reexamined in 2014. Non-cycloplegic automated refraction and visual acuity test were performed at baseline and the 6-year follow-up examination for all participants. In addition, 50% of the participants were randomly selected for axial length (AL), anterior chamber depth (ACD) and lens thickness (LT) measurements using non-contact partial coherence laser interferometry. Lens power (LP) was calculated with the Bennett's equation. A total of 1300 participants were included in current analysis (2008 mean [SD] age, 51.4 [10.6] years; 54.5% women). Mean change in spherical equivalence (SE) was +0.24 (95% confidence interval [CI], +0.19 to +0.30), +0.51 (95% CI, +0.46 to +0.57), +0.26 (95% CI, +0.15 to +0.38) and -0.05 (95% CI, -0.21 to +0.10) diopters (D) for individuals in the age groups of 35 to 44, 45 to 54, 55 to 64 and 65+ years at baseline, respectively. Corneal power, AL and LT increased while ACD and LP decreased during the follow-up. Baseline SE and changes in biometric factors could explain 97.2% of the variance in longitudinal SE change while LP solely could explain 65.2%. Six-year mean change in cylinder power was -0.16 (95% CI, -0.19 to -0.13) D, the axis of astigmatism changed from "with-the-rule" to "against-the-rule" in 16.4% of the participants and to "oblique" in 0.9%. This study confirms a hyperopic shift in the elderly before 65 years old and a myopic shift thereafter. Longitudinal refraction change could be well explained by corresponding biometry changes, especially LP. There is also a shift to "against-the-rule" astigmatism for the adult population.