In patients who visit an emergency room with ocular symptoms, point-of-care ultrasound can quickly identify several emergency diseases. While training of eye ultrasound skills is useful for emergency physicians, hands-on education is risky in pandemic situation such as coronavirus disease 19 (COVID19). As a solution to this, non-face-to-face education via online has been on the rise. The investigators hypothesized that even an online education is enough to perform basic eye ultrasound by emergency physician.

Since the eye is an superficial organ, it has excellent access to ultrasound. Also, the eye has a liquid-filled structure (vitreous body), it is suitable for obtaining some important findings with bedside ultrasound. In patients who visit an emergency room with ocular symptoms, point-of-care ultrasound can quickly identify several emergency diseases. While training of eye ultrasound skills is useful for emergency physicians, hands-on education is risky in pandemic situation such as COVID19. As a solution to this, non-face-to-face education via online has been on the rise. The investigators hypothesized that even an online education is enough to perform basic eye ultrasound by emergency physician.

Inclusion Criteria for doctors:

• Those who have received basic ultrasound education but have not received ocular ultrasound education
• Residents and interns working in the emergency room
• Those who voluntarily agree to participate in the research through the recruitment announcement

Inclusion Criteria for standard patients:

• Adults over 18 years of age without eye-related symptoms
• Those who do not have unusual findings in the eye when scanning by ultrasound
• Those who voluntarily agree to participate in the research through the recruitment announcement

Exclusion Criteria for standard patients:

• Those with a history of ophthalmic diseases
• Those who have a history of ophthalmic surgery such as lens implantation