Macular thickness and its associated factors in a Chinese rural adult population: the Handan Eye Study

Purpose To describe the normal macular thickness and assess its associations. Methods The Handan Eye Follow-up Study was conducted between 2012 and 2013. Macular thickness was scanned by spectral-domain optical coherence tomography (OCT). The built-in software generated a retinal thickness (RT) map, which was divided into three regions (central, internal and external regions) and nine quadrants (one in central and four in internal and external regions each). Results For 5394 subjects in the Handan Eye Follow-up Study, 4793 received OCT examination, 2946 of whom (accounting for 61.46% of the total subjects, mean age 58.91±10.95, 55.6% were women) were included for analysis. The mean RT in central macula, inner and outer rings were (237.38 µm±23.05 µm), (309.77 µm±18.36 µm) and (278.29 µm±14.38 µm), respectively (overall difference, p＜0.001). In inner ring, the RT in temporal was thinnest, followed by nasal, superior and inferior. In outer ring, the RT in superior was thinnest, with the next subfields being temporal, inferior and nasal, respectively. The RT in central macula, inner and outer rings were significantly thicker in men than in women. Multivariate linear regression analysis showed that in central macula, RT increased in subjects younger than 60 years and thinned above the age of 60. In inner and outer rings, RT thinned along with age (p＜0.001). Conclusions This study finds that RT in central macula is the thinnest, followed by the outer ring, the RT in the inner ring is the thickest. Age and gender are related to RT. These associated factors need to be considered when explaining RT.