Best Disease

What is Best disease?

Best disease is an inherited disease that affects the retinas of your eyes. It causes the macula, which is the central part of the retina, to degrade. This means that you can have problems with your central vision, or seeing things that are right in front of you. Best disease may not affect peripheral (side) vision.

Other names for Best disease include vitelliform macular dystrophy or vitelliform dystrophy. Dystrophy is the medical name for the degeneration of an organ.

There’s a form of vitelliform macular dystrophy that doesn’t start when you’re young but instead happens when you get older, usually from 40 to 60 years of age. This is the adult-onset type of the disease.

How common is Best disease?

It’s not clear how many people actually inherit Best disease. One study indicates that Best disease happens in an estimated 1 in 16,500 to 1 in 21,000 people. Another estimate puts the figure at about 1 in 15,000 people and yet another puts the figure at 1 in 10,000 people.

What are the stages of Best disease?

Best disease can go through six stages. They are:

• Stage I - Previtelliform: You probably don’t have symptoms. You haven’t yet developed any of the yellow material underneath your retina.
• Stage II - Vitelliform: This word (vitelliform) means “shaped like an egg.” At this stage, the yellow material is collecting in an egg-like shape. Your vision may still be fine.
• Stage III - Pseudohypopyon: The yellow material may develop into a cyst under the retina.
• Stage IV - Vitelliruptive: The material may begin to damage the cells of the retina and you may notice changes in vision.
• Stage V- Atrophic: The yellow material goes away, but it leaves scars and damaged cells. Some researchers consider this to be the final stage of Best disease.
• Stage VI - Choroidal neovascularization or CNV: Some researchers consider CNV to be the final stage of Best disease, while others think that CNV is a complication of the disease. CNV happens in about 20% of people who have Best disease. Neovascularization refers to new blood vessels that grow in the choroid. The choroid is the layer of tissue between the retina and the sclera (the white part of your eye). Those blood vessels may leak and cause your vision to get worse.

What are the symptoms of Best disease?

You’ll probably find out about Best disease after an eye exam. Sometimes there are no signs and symptoms. When there are, signs and symptoms may include:

• Blurred vision.
• Problems with central vision but not with side vision.
• Seeing things that appear to be shaped oddly, like wavy lines instead of straight lines. This is called metamorphopsia.
• Severe vision loss.
• Different levels of vision or vision loss in each eye.

What causes Best disease?

A genetic condition causes Best disease.

Best disease is an autosomal dominant condition. This means that only one parent needs to have an altered gene to pass it on. It also means that half of the children of a parent with an autosomal trait will get that particular trait. In this case, the trait is Best disease.

The gene that’s affected in Best disease is the gene that can be affected in some types of retinitis pigmentosa, a group of inherited eye diseases.

How is Best disease diagnosed?

In many cases, a healthcare provider will find Best disease when you’re between five and 10 years old or by the time you’re 20 years old.

An eye care specialist will first take a medical history and do an eye exam. They may also ask for imaging tests and measure how thick your choroid is. Tests may include:

• Fluorescein angiography: This is an imaging test that uses dye to show blood vessels.
• Optical coherence tomography: This type of noninvasive imaging test uses reflected light to create pictures of the back of your eye.
• Color fundus photography: This type of imaging shows your retina, the related blood vessels and the optic nerve head.
• Ophthalmic electrophysiology: This term describes a series of eye tests that measure electrical activity.
• Genetic tests: These tests will give the provider information about your genes.

The eye care provider may also want to speak to family members or examine their eyes.

How is Best disease treated?

There’s no cure for Best disease at this time.

Managing Best disease depends on the symptoms and stage of the condition. Once it’s diagnosed, you’ll need to keep a regular schedule of eye appointments so any changes can be found early.

In early stages, you might not need any treatment. You may need treatment for other conditions, such as corrective lenses for refractive errors. People with Best disease often have farsightedness. If you have cataracts, you may need cataract surgery.

If you have choroid neovascularization and you’ve developed a choroid neovascularization membrane, the provider may suggest the following to stop the growth of new blood vessels:

• Anti-vascular endothelial growth factor agents: These are medications injected into the vitreous cavity of your eye. They’re intended to stop new blood vessels from growing.
• Laser therapy: This treatment uses lasers to close off the blood vessels.
• Photodynamic therapy: This treatment combines a laser and a drug that’s activated by light to damage the blood vessels and stop leaking.

Your provider may also suggest you use low vision aids like magnifying devices and other helpful tools.

Researchers are working on treatments or preventatives that use genetic material. Gene therapy is experimental.

How can I reduce my risk of developing Best disease?

You can’t stop yourself from developing Best disease. If you have the genetic background to pass on Best disease, you may be interested in genetic counseling.

What can I expect if I have Best disease?

Best disease isn’t fatal, but it’s not curable, either. You won’t go blind from Best disease, but you may have low vision.

How do I take care of myself?

Certain types of foods may help with eye health. Consider eating fish a few times per week and consuming leafy green vegetables along with other types of fruits and vegetables and nuts.

If you have Best disease, you should have regular healthcare appointments, including regular eye care appointments. Let the care provider know about any changes in your vision or your health. You may want to ask questions like:

• Can you recommend a genetic counselor to help me decide about having children?
• Am I eligible to participate in a clinical trial?
• Can you recommend an optometrist that specializes in low vision?
• Is gene therapy an option for treatment?

What is the difference between Best disease and Stargardt disease?

Both Stargardt disease and Best disease are genetic disorders that affect the macula. But they’re caused by changes in different genes.

Stargardt disease may lead to yellow or white flecks in your retina. Best disease may cause a large yellow oval to appear because a cyst forms under your macula.

A note from Cleveland Clinic

Living with a condition that causes low vision brings its own challenges. However, there are many resources that can make things easier if you have Best disease. Ask a healthcare provider for recommendations for services.