What is Macular Degeneration?

Macular degeneration  (AMD) is a disease associated with age that gradually destroys the sharp, central vision.  This is the vision we use for driving and reading.  In some cases the lost of vision can be so slight or gradual that the person does not notice it.  In other cases there can be fast progression.
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AMD is a leading cause of vision in people over 60.  There are two types of AMD, wet and dry.

What is the Macula?

The macula is the center part of the retina that contains the highest density of light senstive cells. This area of the retina gives us our reading and driving vision.

What is Dry AMD?

In Dry AMD the central light senstive cells slowly break down and are lost.  The retina gradually thins out and visional  function can decrease.

What is Wet Macular Degeneration?

Wet AMD occurs when abnormal blood vessels grow from behind the retina under the macula.  Those blood vessels are fragile and frequently leak fluid or blood under the retina.  This can cause sudden loss of vision.

An early symptom of wet AMD is that straight lines appear wavy. Dry AMD can change to wet AMD.

What are Drusen?

Drusen are yellow deposits under the retina.  The relations between drusen and macular degeneration is unknown but an increase in size or number of drusen is associated with macular degeneration. We examine the retina carefully for drusen and look for a change in drusen.

How is Dry AMD Treated?

Once Dry AMD reaches an advanced state no treatment can prevent vision loss.  However taking antioxidants and zinc can significantly reduce the risk of advanced AMD.  The Age-Related Eye Disease Study (AREDS) found a specific high dose vitamin formula that decreases the risk of AMD [ Insert Vitamin Pages] Can diet alone or a daily multivitamin reduce the risk of AMD? No, the level of antioxidants and zinc are considerably higher in the AREDS formula.

How Is Wet AMD Treated?

One of the most exciting developments in Ophthalmology has occurred recently.  Lucentis (ranibizumab) from Genetch has been shown to effectively treat wet AMD. Vision is maintained in 95% of patients who have undergone treatment and improved vision in 40%.

This is much better than past results with lasers or other medications.  Lucentis also has been shown to work in all types of wet AMD.  In the past many cases of wet AMD were classified as occult and laser was ineffective.  Lucentis does not help dry AMD or improve vision if scar tissue has formed in the retina.

How Does Lucentis Work?

In the late 1970’s scientists sought to fight cancer by cutting off the cancer’s blood supply. Cancer cells and normal cells when under stress by such things as hypoxia inflammation, or hormones secrete a vascular endothelial growth faster (VEGF) to cause blood vessel growth.  There are a large number of vascular endothelial growth factors – VEGF-A, VEGF-B-C and D and placental growth factors.VEGF is also an enhancer of vascular permability and this will cause tissue edema or swelling.Anti-VEGF proteins have been synthesized and can block some of the VEGF proteins and thus decrease blood vessel growth and edema. Lucentis can block VEGF-A.These proteins were first approved for use in colon cancer and are widely used today.  They are now used in the eye to dry-up abnormal blood vessels and decrease edema.

How Are These Medications Given?

Unfortunately these medications can not be taken by mouth because the protein  would not be absorbed.
The medication needs to be injected in the eye.  The usual course is monthly for 48 months.  Lately some doctors are administering monthly for four months then every three months afterwarnds for 48 months.
This medication could be given intravenously and indeed this has been done and shown to work.  But side effects are higher this way. There is increased blood pressure and increased clotting when anti-VEGF proteins are given this way.