Purpose: To report baseline information for a medical university cohort with the aim of exploring related factors for adult myopic progression. Methods: This study included Chinese freshmen students from a medical school in Guangzhou, China. All participants underwent detailed eye examinations, including cycloplegic refraction, ocular biometry and swept source optical coherence tomography. Choroidal thickness (CT) measurements were performed at nine locations in the macular area. Eye care habits and physical activities were measured by questionnaire. Results: The mean age of the study population (N = 307) was 18.8 ± 2.3 years, and 46.3% were male. The prevalence of myopia and high myopia was 92.8% and 21.1%, respectively. In emmetropia (spherical equivalent, SE -0.49D to +0.5D), mild to moderate myopia (SE -0.50D to -5.99D) and high myopia groups (SE <-6.00D), the average subfoveal CT was 300.3 ± 62.1 μm, 219.3 ± 65.4 μm and 194.0 ± 59.7 μm, respectively. In all eyes, the temporal CT was the thickest among all of the locations in the macular area, and the CT was thinnest nasally. Gender, axial length (AL), anterior chamber depth (ACD) and intraocular pressure (IOP) were the strongest related factors for subfoveal CT in mild to moderate myopia, while AL was the only significant determinant for subfoveal CT in highly myopic eyes. Conclusions: The prevalence of myopia was high in Chinese medical students. Macular CT was generally thinner in highly myopic eyes. Our study provided baseline information for the medical school cohort, including CT, AL, ACD, IOP and eye care habits.
Keywords: Chinese; Myopia; choroidal thickness; medical students; risk factors.