Best disease

How is Best disease diagnosed?

Best disease can be diagnosed by looking for lesions that resemble egg yolks at the back of the eye, seen in the vitelliform stage. There are other tests available to confirm the diagnosis.

• OCT is useful for localizing the lesion and determining its thickness, which may reveal lipofuscin and fluid buildup in the RPE.
• Autofluorescent imaging can detect the build-up of fatty deposits in the back of the eye.
• Best disease can also be detected in patients through an electrophysiological test called an EOG. An EOG test measures the health and activity of the RPE cells in the back of the eye. EOG recordings are used to calculate Arden ratios, which are generally 1.5 or lower in patients with Best disease.
• The ERG test is also used in the diagnosis of patients with the Best disease. It is used to measure retinal function.
• Another way to diagnose the Best disease is by genetic testing.

What are the different stages of Best disease?

Best disease progresses through six stages. They are discussed below:

Stage I - Pre Vitelliform

At this point, you are likely to not be experiencing symptoms and you have not yet developed the yellow material below your retina.

Stage II - Vitelliform

This term vitelliform means shaped like an egg. At this stage, yellow material is forming an egg-like shape. You may still have good vision.

Stage III - Pseudohypopyon

It is possible that the yellow material that was forming under the retina at stage 2 will develop into a cyst.

Stage IV - Vitelliruptive

Your retina may begin to be damaged by the yellow material, and your vision may be affected.

Stage V- Atrophic

As the yellow material disappears, it leaves scars and damaged cells behind. This stage is considered to be the final phase of Best disease by some researchers.

Stage VI - Choroidal neovascularization or CNV

There are some researchers who believe that CNV is the final stage of Best disease, while there are others who believe that it is a complication of it. About 20% of people with Best disease develop CNV. Choroid neovascularization refers to the development of new blood vessels. Those blood vessels may leak, causing your vision to deteriorate.

Treatment and prevention of best disease

Unfortunately, as of now, there is no effective medical or surgical treatment for Vitelliform macular degeneration. There is currently research being conducted on gene therapy for the treatment of different types of inherited macular dystrophies. By replacing the faulty gene with a new functioning gene, gene therapy aims to correct the problem. The research is in the beginning stages and may take a while before it could potentially become a useful treatment, however this kind of research is a positive step in the right direction.

Clinical Trials using gene therapy for Best’s disease

One of the most exciting trials is in the field of gene therapy used for treating Best’s disease. Research was done at the University of Pennsylvania and the University of Florida that demonstrated the efficacy of treating best disease through gene therapy in Dogs. The approach taken has also been used in the FDA approved retinal gene therapy for Leber’s congenital amaurosis. The hope is that this approach that has been shown to work in both dogs and in other FDA approved treatments for retinal disease, will also translate into an effective treatment for Best’s disease. Clinical trials are underway, and your low vision optometrist or ophthalmologist will inform you if the treatment becomes available.

Prevention

Head trauma may increase the risk of developing the Best disease. Therefore, If you're at risk for a head injury, it's a good idea to take extra precautions, such as avoiding contact sports and wearing a helmet while cycling.

Anti-VEGF injections

Laser therapy and anti-VEGF injections can be used to treat new blood vessels. It may not lead to a significant improvement in sight, but treating blood vessels can prevent the macula and eyes from further damage.

Diet and smoking

There is evidence that smoking accelerates other forms of macular disease, so stopping smoking might help delay progression of Best disease as well. Currently, no research has indicated that diet can help to slow the progression of the Best disease. A diet high in fresh fruit and vegetables, however, may be beneficial for maintaining eye health.