Normal macular thickness measurements using optical coherence tomography in healthy eyes of adult Chinese persons: the Handan Eye Study

Abstract

Purpose: To describe macular thickness measured by optical coherence tomography (OCT) in healthy eyes of adult Chinese persons.

Design: Population-based cross-sectional study.

Participants: Chinese adults aged 30+ years who were residents of Handan, North China.

Methods: The Handan Eye Study is a population-based study of eye disease in Chinese persons. Eligible residents underwent a comprehensive ophthalmic examination including OCT (Stratus OCT, Carl Zeiss Meditec Inc., Jena, Germany). Fast macular thickness scans were performed over maculae within 6 mm in diameter, divided into 3 regions (central, inner, and outer, with a diameter of 1, 3, and 6 mm, respectively) and 9 quadrants (1 in the central region and 4 each in the inner and outer regions). Retinal thickness (means and standard deviations) was calculated by OCT mapping software, presented for foveal minimum, central macula (within 1 mm diameter), and inner and outer regions divided by 8 quadrants.

Main outcome measures: Macular thickness measured by OCT.

Results: Of the 6830 participants (90.4% response rate) examined, 2230 eyes of healthy subjects with high-quality OCT scans were selected (32.7% of participants; mean age, 46.4+/-9.9 years, 58.4% were women). The mean foveal minimum, central, inner, and outer macular thicknesses were 150.3 (18.1) microm, 176.4 (17.5) microm, 255.3 (14.9) microm, and 237.7 (12.4) microm, respectively (overall differences, P<0.001). The mean foveal volume was 0.139 (0.014) mm(3), and the mean total macular volume was 6.761 (0.516) mm(3). In the inner region, the nasal quadrant was thinner than the superior and inferior quadrants, and in the outer region, the nasal quadrant was the thickest (P<0.001). Age was positively correlated with foveal (beta coefficient = 3.582) and central macular (beta coefficient = 2.422) thicknesses. The foveal minimum, central, inner, and outer macular thicknesses were significantly greater in men than in women. Fasting plasma glucose was negatively correlated with central macular thickness (2.416 mm reduction per millimole/liter increase in glucose), and axial length was positively correlated with central macular thickness (2.138 mm increase per millimeter increase in axial length).

Conclusions: Normal macular thickness measurements using OCT in a large population-based sample of adult Chinese persons aged 30 to 85 years were generally thinner in the foveal and central macular areas than measurements reported in other populations. Age and axial length were positively correlated with macular thickness.