Ultrasound is an imaging technique that uses sound waves to improve visualization of the back of your eye (retina). Ultrasound is often used to evaluate the retina and vitreous gel that fills the eye when they cannot be visualized during an eye exam. Your doctor will hold a small probe on the outside of your eye lid while your eyes are closed, and he/she may ask you to look in different directions. Ultrasound imaging of the eye does not hurt and only takes a few minutes. It can provide valuable information to help your doctor make an accurate diagnosis and appropriate treatment plan.