We designed this study to identify the epidemiological characteristics and trends of various types of ocular trauma in the population of the Republic of Korea. We conducted a nationwide, populationbased, cross-sectional study using the Korean national Health insurance claims database for January 2010 to December 2018. We compiled the monthly numbers of patients diagnosed with hyphema and those who received open reduction surgery due to orbital blowout fracture (Bof), primary closure of the cornea or sclera (pccS), or intraocular foreign body (iofB) removal. We obtained annual and monthly incidence rates, and differences according to age, sex, yearly trends, and seasonal variations. The incidence rate (per 100,000 person-years) was high in the order of hyphema (18.43), BOF (11.58), PCCS (1.99) and IOFB removal (0.39). Male predominance was evident in all types of major ocular trauma, but the age distribution varied with the type: hyphemas were most prevalent at 10-14 years of age, BOFs at 25-29 years of age, and open globe injuries (OGIs) at age 60 and older. Although all types of trauma showed significant seasonality, hyphemas (amplitude: 174.81) and BOFs (23.17) showed higher amplitudes compared to OGIs (PCCS: 11.96; IOFB removal: 6.72). While the incidence of blunt trauma injuries, including hyphemas and orbital BOFs, decreased steadily from 2010 to 2018, that of OGIs showed no remarkable change. Ocular trauma is an important cause of visual impairment 1-3 , and the World Health Organization has reported that globally 55 million people experience serious ocular trauma every year 4. Depending on the type and severity of the trauma, not only the cost for treatments could be high, but also it could remain irreversible poor visual impairments following the injury 5. Additionally, blindness under the age of 20 is predominantly due to ocular trauma and its socioeconomic cost is very large 2, 6-8. The eyeball injury is classified as either closed globe injury or open globe injury (OGI) 9-11. The OGI, defined as full thickness wound in cornea or sclera, is classified as rupture and laceration. Corneal or scleral laceration is further classified as perforation, penetrating injury, and intraocular foreign body (IOFB) 9. Usually, the OGIs require primary closure of the cornea or sclera (PCCS) or surgery of IOFB removal. Epidemiological studies identifying trends or causes of ocular trauma are essential for establishing appropriate prevention measures. However, previous reports have limitations such as targeting a specific type of ocular trauma 12 , analyzing only emergency visits 1, 2 , small populations 3 , or including a limited number of institutions 11. In the present study, we sought to identify the epidemiological features of major types of ocular trauma, including closed globe injuries such as hyphemas and orbital blowout fractures (BOFs) and OGIs, based on the Korean National Health Insurance (NHI) claims database. Results Hyphema. From 2010 to 2018, the average annual incidence (per 100,000 person-years) of hyphe...