Dry Macular Degeneration – What is Drusen?

Drusen deposits associated with dry macular degeneration are typically yellow in colour.  The presence of drusen does not necessarily indicate the development of dry macular degeneration, but there is a strong correlation between the two.  The presence of drusen substantially raises ta person’s risk of developing either form of the eye disease – dry or wet macular degeneration.

Age related macular degeneration is a progressive eye disease that attacks the central vision.  With dry macular degeneration, the most common form of this eye disease affecting approximately 90 percent of those diagnosed, the loss of vision is associated with the accumulation of drusen in the retina.  Drusen deposits on the macula cause atrophy which halts the functioning retinal cells resulting in vision loss.

Drusen is thought to be associated with the metabolic processes occurring throughout the body.  As cells perform their tasks they produce by-products which are carried throughout the body.  Most of these by-products are disgarded, it is thought that some deposit and accumulate in the eye forming drusen.

Drusen deposits may be scattered or concentrated, depending on the stage of dry macular degeneration a person is at.  In the early stages of dry macular degeneration, the accumulation and deposits of drusen may be small.  There is little or no impact on vision and the person typically will not have any symptoms indicating a problem or signaling the beginnings of macular degeneration.  As the deposits of drusen grow in accumulation, medium size deposits form and symptoms develop such as blurred vision.  People will generally require more light and will often indicate a loss of vision that is more pronounced in the centre of the eye.  This is typically when most patients are diagnosed with dry macular degeneration.

Once the eye disease progresses to where it is considered advanced dry macular degeneration, retinal damage has occurred and there is an inability of the light sensitive cells in the retina to process light.  The drusen deposits at this stage may be very large and very concentrated, resulting in more blurry vision which gets larger and larger and darker with time.

There is no known treatment for macular degeneration but the progression of drusen deposits have been shown to be slowed with antioxidants and zinc supplements in the diet.

A controversial treatment called rheopheresis is being explored for a treatment of dry macular degeneration.  Rheophersis is a treatment that is similar to kidney dialysis where teh blood is filtered to remove the by-products associated with the metabolic processes of the body.  This treatment hopes to remove the elements thought to be depositing in the eye and forming drusen.  Clinical trials are currently underway to determine if this treatment is a viable option for treating dry macular degeneration and for removing the drusen deposits.

Rheopheresis has been shown to be effective in slowing the progression of dry macular degeneration in limited trials.  However, this treatment for dry macular degeneration is only currently available in Canada and Germany.

Laser treatment for the removal of drusen has been shown to be ineffective.  This is partially due to the fact that atrophy has already occured and the function of the cell has already been loss prior to the removal of the drusen.

People diagnosed with dry macular degeneration must have regular eye exams to monitor the drusen deposits and the progression of the eye disease.  Dry macular degeneration can progress into the more serious form of wet macular degeneration.