A B-scan is an ultrasound device that emits high frequency sound waves to provide a cross-sectional, two-dimensional view of eye tissue that is not visible in other ways. These sound waves are reflected by eye tissues and orbital structures and converted into electrical pulses, which are displayed on a printout as bright spots on a black background.
To perform a B-scan examination, the doctor applies a topical anesthetic and then moves a hand-held instrument called a transducer over the eye. As the instrument is oriented in various directions, it provides different views of the inside of the eye which can be recorded with a camera. If you have a vitreous hemorrhage, your doctor will be unable to examine the retina visually, so he or she must rely on the B-scan to detect any abnormalities.