High myopia and its associated factors in JPHC-NEXT Eye Study: a cross-sectional observational study

Abstract Background The increasing prevalence of high myopia has already been noted. It is important to know the factors associated with high myopia to prevent complications. In the present study, we investigated the epidemiological characteristics of high myopia and determine its related factors among a Japanese adult population. Methods JPHC-NEXT Eye Study was performed in Chikusei-city, located in a rural area in mid-east Japan in 2013-2015. A cross-sectional observational analysis was conducted to investigate prevalence and related factors of high myopia through this study. A total of 6,101 participants aged ≥40 years who have no history of ocular surgeries were included in this study. High myopia was defined as a spherical equivalent refraction of ≤ -6.00 diopters (D) based on the American Academy of Ophthalmology. Potential high myopia-related factors included intraocular pressure (IOP), corneal structure, corneal endothelial cell density, age, height, body mass index, heart rate, blood pressure, glutamic-oxaloacetic transaminase (GOT), glutamate pyruvate transaminase (GPT), gamma-glutamyl transpeptidase (GGTP), total cholesterol (T cholesterol), triglyceride, high-density lipoprotein cholesterol (HDL cholesterol), low-density lipoprotein cholesterol (LDL cholesterol), blood glucose (glucose), Hemoglobin A1c (HbA1c), creatinine, and current history of systemic and ocular disorders. The odds ratios of high myopia associated with these factors were estimated using the logistic regression models adjusted for the associated factors. Results The prevalence of high myopia was 3.8% among the men and 5.9% among the women with a significant difference. Age was inversely associated with high myopia. We also found a positive association between IOP and high myopia. Other factors were not associated with high myopia for either men or women. Conclusions In this community-based sample, age was inversely, and IOP was positively associated with high myopia in both the men and the women.