Vitreous hemorrhage is the leakage of blood into the vitreous humor, the clear, gel-like substance that fills the space between the lens and the retina. This event can cause symptoms ranging from a sudden shower of floaters to a profound and immediate loss of vision. When bleeding occurs, it can prevent a doctor from performing a complete eye examination. In these situations, ocular ultrasound becomes a primary diagnostic tool, allowing for a non-invasive look at the structures in the back of the eye.
Why Ultrasound is Used for Vitreous Hemorrhage
An eye filled with blood presents a significant challenge for an ophthalmologist. Standard examination tools, like an ophthalmoscope, rely on a clear path to see the retina, the light-sensitive tissue at the back of the eye. When a vitreous hemorrhage is dense, it makes a direct view of the retina impossible, similar to trying to see the bottom of a muddy pond. The blood obscures details, preventing the identification of the bleeding’s source or any associated damage.
This is where B-scan ultrasonography becomes indispensable. Ultrasound technology uses high-frequency sound waves to generate an image of the eye’s internal structures. These sound waves can travel through the blood that light cannot penetrate, reflecting off different tissues to create a detailed, two-dimensional picture. This allows specialists to “see” through the hemorrhage to assess the health of the retina and other structures, which is fundamental for determining the cause of the bleeding.
The ability to bypass the opaque blood is the principal reason for using ultrasound. Without this technology, doctors would have to wait for the blood to clear on its own, a delay that could allow a serious underlying condition, such as a retinal detachment, to cause irreversible vision loss.
The Ocular Ultrasound Examination
The ocular ultrasound examination is a straightforward and non-invasive procedure. The most common method used is a B-scan, which provides a cross-sectional view of the eye. The process is performed with the patient either sitting upright or lying down, and it does not require any preparation like fasting or pupil dilation.
To begin the test, a technician will apply a small amount of water-based gel to the probe or directly onto the patient’s closed eyelid. This gel helps ensure a solid connection so that the sound waves can travel effectively from the probe into the eye. The probe, a small, handheld device, is then gently placed against the eyelid to capture the images.
The entire examination is painless and relatively quick, often completed within minutes. Patients may be asked to look in different directions—up, down, left, and right—while the probe is in place. This movement allows the specialist to view all parts of the retina and observe how the contents within the eye shift, providing additional diagnostic clues.
What the Ultrasound Reveals
The hemorrhage itself appears on the scan as low-reflective dots or web-like echoes floating within the vitreous cavity. By having the patient move their eye, a technique called kinetic echography, the sonographer can observe the movement of these echoes. This helps to confirm the presence of blood and can sometimes suggest how long it has been there; older, clotted blood may move less freely.
The scan can detect a posterior vitreous detachment (PVD), a common age-related condition where the vitreous gel pulls away from the retina. A PVD appears on the scan as a thin, mobile line. While a PVD itself is not always an emergency, its presence in combination with a vitreous hemorrhage increases the likelihood of a more serious issue.
An ultrasound can identify a retinal tear or a full retinal detachment. A retinal detachment shows up as a brighter, more reflective, and typically less mobile membrane that remains tethered to the optic nerve. The scan can also identify less common causes of bleeding, such as tumors or issues with blood vessels.
How Ultrasound Results Guide Treatment
The findings from the ocular ultrasound directly determine the subsequent course of action, dictating both the urgency and the type of treatment required.
If the ultrasound reveals only blood in the vitreous without any accompanying structural problems like a retinal tear or detachment, the management approach is often conservative. In these instances, the doctor may recommend a period of observation, allowing the blood to settle and clear on its own. The patient might be advised to keep their head elevated to help the blood pool in the lower part of the eye, clearing the central axis of vision.
Conversely, if the ultrasound identifies a retinal detachment, the situation is treated as a medical emergency requiring prompt surgical intervention. The standard procedure is a vitrectomy, a surgery to remove the blood-filled vitreous gel and repair the detached retina. This immediate action is necessary to prevent permanent vision loss.