The vitreous is the gel-like substance that makes up approximately two-thirds of the eye’s volume and is located in between the lens in the front of the eye and the retina in the back of the eye. In normal, healthy vitreous gel, there are no blood vessels; but diseases such as diabetic retinopathy can lead to the development of new blood vessels which can grow into the vitreous gel. These blood vessels are often fragile and susceptible to leaking blood and fluids.
A vitreous hemorrhage occurs when one of these blood vessels ruptures and causes bleeding within the vitreous gel, causing visual symptoms. Normal blood vessels may also rupture, although less common, as a result of force from a retinal tear or detachment. Patients with vitreous hemorrhage usually notice a sudden, significant increase in the number and size of floaters blocking their vision. Severe bleeding can also cause vision to appear blurry, cloudy or hazy.
When symptoms occur, it is important for patients to seek prompt medical attention. Dr. Brown will examine your eye along with your medical history to determine the cause of the hemorrhage and then recommend an appropriate treatment. Treatment for a vitreous hemorrhage may include vitrectomy, cryotherapy, laser photocoagulation, or intravitreal injections.
Retinal Vein Occlusion
Blood and nutrient circulation to and from the surface of the retina is mostly done through one vein and one artery. If these passages or any of the smaller branches connected to them are blocked, blood flow to the retina can become seriously disrupted. Blockage of one of these passages is known as occlusion, and can result in sudden vision loss.
The retinal vein carries blood away from the body, and may cause blood to build up and hemorrhage if it is blocked. Retinal vein occlusion, also known as venous stasis retinopathy, can also cause swelling, bleeding and growth of abnormal blood vessels which can in turn lead to other serious eye diseases.
This condition is most common in men and women over the age of 50, although the risk continues to increase with age. Other risk factors may include high blood pressure, high cholesterol, diabetes, smoking, glaucoma and, rarely, blood clotting and inflammatory conditions.
Although there is no cure for retinal vein occlusions, there are several treatment options available to help minimize risks, treat symptoms, and prevent further vision loss. Vascular endothelial growth factor (VEGF) is a chemical that is produced in the eye in patients with retinal vein occlusions and other eye diseases. VEGF can cause blood vessels to leak, causing swelling in the retina. This swelling is called macular edema.
Medications that block VEGF can slow or stop the leakage. This often results in improved vision and a better prognosis for future vision. Avastin, Lucentis and Macugen are medications that can effectively block VEGF. Laser photocoagulation and steroid medications may also be used to help improve the retinal edema. The best treatment for each patient depends on the severity and location of the blocked vein. Dr. Brown will discuss with you the recommended treatment strategy for your specific situation.
Flashes and Floaters
Flashes and floaters are symptoms of the eye that commonly occur as a result of age-related changes to the vitreous gel. When we are born, the vitreous is firmly attached to the retina and is a thick, firm substance without much movement. But as we age, the vitreous becomes thinner and more watery, and tissue debris that was once secure in the firm gel can now move around inside the eye, casting shadows on the retina.
Flashes in vision occur as a result of pressure on the retina in the back of the eye, and causes patients to see flashing lights or lightning streaks. Floaters occur when fibers move across the vitreous and into your field of vision, causing patients to see specks, strands, webs or other shapes as the fibers cast shadows on the retina. These spots are most visible when looking at a plain, light background.
Although flashes and floaters are common, especially as we age, it is important to see Dr. Brown if you experience them, as they may indicate a retinal tear or hole. Dr. Brown can distinguish between harmless flashes and floaters, and those that may require treatment for an underlying condition. Most flashes and floaters will become less noticeable with time as patients adjust their vision. Although these floaters are harmless, it is important to continue to receive regular eye exams to ensure that any permanent changes to your vision do not occur.
Located at the back of the eye, the retina is attached to the vitreous, the gel-like substance that makes up for most of the eye’s volume. Although the vitreous begins as a thick substance with a firm shape, the consistency of the gel changes and becomes thinner and more watery as we age. A change in the shape of the vitreous can cause it to pull away from the retina and leave a tear. A retinal tear leaves the retina unprotected and can allow fluid to travel between the retina and the wall, which may lead to retinal detachment.
Retinal tears may occur in patients with myopia (nearsightedness), as the condition may cause the vitreous to pull away from the retina. Although a retinal tear does not cause pain, patients may experience flashes or floaters in their field of vision, a reduction of vision, a shadow or curtain forming in the peripheral vision, or other vision changes. It is important to see Dr. Brown at the first sign of a retinal tear.
Early detection of a retinal tear can often prevent the retinal from detaching through prompt treatment. A retinal tear is usually treated with a laser to burn the area around the tear, causing it to scar and seal the retina to the tissue underneath it. This prevents fluid from flowing through the tear and leading to retinal detachment. Treatment for a retinal tear is usually effective in relieving symptoms and preventing retinal detachment from occurring.