B-scan ultrasonography is a form of ocular ultrasound which uses the reflection of sound waves and produces a cross-sectional image of the internal structures of your eye. An ultrasound is used to evaluate the inside of an eye when a condition may limit what the doctor can see by just looking at the eye. B-scan ultrasound can see through corneal scarring or swelling, advanced cataracts and vitreous hemorrhage-which is bleeding inside the eye. They may be helpful in the diagnosis of tumors, foreign bodies, ocular inflammation and retinal detachments.