Retinal vein occlusion is a common eye problem.  A major cause of retinal vein occlusions is arteriolosclerosis or the thickening of the blood vessel walls.  Thickening of the walls of your blood vessels occurs in response to increased blood pressure.  This arteriolosclerosis leads to a compression of the ocular veins which course under the arteries.  This compression leads to partial occlusion of the vein, development of a blood clot, and damage to the blood vessel wall.  When blood cannot drain properly, it leads to bleeding and leakage of fluid from blocked blood vessels.  Oxygen delivery to the retina is reduced and problems such as blurred vision, blind spots, bleeding in the eye, or a painful type of glaucoma can ensue.

What causes a retinal vein occlusion?

Risk factors for retinal vein occlusion include age (your risk increases 10-fold from age 40 to age 65), hypertension, high cholesterol, diabetes, or elevated eye pressure. In the rare cases where retinal vein occlusion is not explained by these factors, lab work must be done to search for other, uncommon medical conditions that lead to an increased tendency for blood to clot.

What does RVO mean?

Ophthalmologists use different terminology to describe retinal vein occlusions, depending on where the blockage in the eye occurred.  A BRVO, or branch retinal vein occlusion, occurs in one of the smaller veins in the eye.   A BRVO may only affect one-quarter or one-half of the retina, leaving other parts of the retina to function normally. In contrast, a CRVO, or central retinal vein occlusion, affects the main venous drainage of the eye.  Typically, a central retinal vein occlusion is more severe than a BRVO, and patients experience worse vision and develop more complications due to the poor blood flow patterns that result due to the blockage of the main drainage of the eye.

What is your ophthalmologist looking for?

When a retinal specialist looks inside your eye, he can see vessels which are wider and curvier than normal.  This finding indicates your vessels may have increased pressure due to an outflow problem which occurs in any vein occlusion.  The doctor will see many hemorrhages occurring within the retinal layers.  In addition, a swollen optic nerve and swelling in the central retina are often found.  Additional testing (e.g. optical coherence tomography and fluorescein angiogram) done by your retinal specialist can further determine the level of retinal swelling and show how the vein occlusion has affected the blood flow to the eye.

Here is a patient who has suffered a branch retinal vein occlusion.

Diabetic retinopathy is a serious public health issue.  

Diabetic retinopathy is the leading cause of blindness in people of working age in developed countries.  In 2012, nearly 30 million Americans were diagnosed with diabetes per the American Diabetes Association.

Diabetic retinopathy is the visible manifestation of longstanding diabetes in the retina.  

Changes in the eye caused by diabetes are due to a combination of the longevity of disease duration and degree of blood sugar control.  Diabetes will affect the eyes of nearly all patients with sufficient duration of uncontrolled disease.  If left untreated, diabetic retinopathy can result in eye pain over time and can even result in permanent vision loss or blindness.

As with many eye problems, symptoms may not manifest until late in the disease.  Common symptoms include:

• Decreased vision
• Floaters
• Blind spots
• Distortion
• Eye pain
• Loss of vision
• Poor color vision
• Poor night vision

The number one risk factor for the development of diabetic retinopathy is the duration of diabetes.

In short, the longer you have diabetes, the more likely you are to develop bleeding in the retina.  Other factors include poor blood sugar control, poor blood pressure control, high cholesterol, pregnancy, and barriers to healthcare access.

Diabetes causes damage to the small blood vessels in the eye.  

This leads to poor blood flow in the eye.  A low oxygen state triggers a series of biochemical and cellular events that can cause damage to the eye over time.

Diabetic retinopathy progresses through a series of very predictable stages. 

Diabetic retinopathy begins as a “non-proliferative” disease, meaning that hemorrhages begin to form in the retina and small vascular abnormalities form within the retina.  If left untreated, the diabetic retinopathy becomes increasingly more severe, until it eventually enters a proliferative stage.

This proliferative stage is identified by the development of abnormal, new blood vessels.  These blood vessels can lead to hemorrhaging with the gel in the middle of the eye (vitreous hemorrhage), scar tissue formation on the retina, retinal detachment, or a painful type of glaucoma (neovascular glaucoma).  The abnormal vessels can be treated with a laser procedure called pan-retinal photocoagulation (PRP).  If left untreated, an eye will become blind and painful over time. Ophthalmologists and retina specialists like to identify and treat the disease before it gets to the “proliferative” stage.

Patients can help prevent diabetic retinopathy by getting a yearly dilated eye exam. 

Eye exams help with early detection and prevention.  The American Academy of Ophthalmology recommends an eye exam at the time of diagnosis of diabetes then yearly for Type 2 diabetics.  Intensive blood sugar control both reduces the risk of progression and slows progression in most patients.

Treatment options include close observation, laser, or injections of medications like Avastin, Lucentis, and Eylea into the eye.  Ophthalmologists commonly work with primary care doctors and endocrinologists in patients at high risk for vision loss.

For further reading, check out the American Academy of Ophthalmology’s Preferred Practice Patterns regarding diabetic retinopathy.

It is very important for diabetics to have their eyes checked annually for any signs of diabetic retinopathy.  Call today if you are due for your yearly eye exam – 941-777-5000.