Macular Diseases
What is the macula?
 The macula is an oval area in the retina on the back of the eye where the
photoreceptors are most dense and where the light is focused. The center of
the macula is called the fovea. The macula is responsible for the central
(or reading) vision. The macula has the greatest concentration of
photoreceptor cells, and when the eye is directed at an object, the part of
the image that is focused on the fovea is the image most accurately seen.
What is macular degeneration?
In the western world, age-related macular degeneration (AMD) is the
leading cause of legal, irreversible blindness among people 50 years of age
and older.
- Dry macular degeneration (atrophic AMD) is the most common
form of macular degeneration and
can progress to cause severe central vision loss. This disease
progresses slowly and most people usually maintain some central
vision in at least one eye. The condition always starts as "dry" AMD. "Dry" AMD
refers to the slow degenerative process that occurs without any formation
of abnormal
blood vessels. The
recent Age-Related Eye Disease Study (AREDS) demonstrated that
the progression of "dry" AMD could be slowed with vitamin supplementation.
This study demonstrated the benefits of taking Vitamin C, Vitamin
E, beta carotene, and zinc along with copper. Several vitamin
preparations
containing the appropriate amounts of these vitamins are currently
available and we encourage patients with AMD to discuss these
various
vitamin preparations with their eye care specialist. Previous
studies have also suggested that green leafy vegetables may be
beneficial and smoking may
be detrimental to patients with AMD.
- "Wet" macular degeneration (exudative or neovascular AMD) is caused by blood
vessels growing under the retina in the macula. "Wet" AMD always arises from
pre-existing "dry" AMD. These blood vessels leak fluid, protein, lipid and blood.
Eventually, if untreated scar tissue forms under the macula and central vision
is destroyed. There are several treatments approved for "wet" macular degeneration.
Click here more information about macular degeneration at Bascom Palmer Eye Institute
What are the symptoms of macular degeneration?
There is no pain associated with dry or wet AMD. The most common symptom
of dry AMD is slightly blurred or fuzzy vision requiring greater
illumination to see greater details. Also, an inability to recognize faces
at a distance may develop.
As dry AMD progresses, a blurred spot develops in the center of vision. With
time, the spot may get bigger and darker, reducing central vision. Often,
when dry AMD is limited to one eye patients do not complain of visual
changes because of the ability of the other healthy eye to see clearly,
allowing for driving, reading, recognizing faces and seeing fine details.
Symptoms of wet AMD may be that straight lines, such as sentences on a
page, appear wavy; rapid loss of central vision; and a blurred or blind
spot in the center of vision.
How is macular degeneration diagnosed?
If an ophthalmologist suspects a patient of having AMD, he or she may:
- perform a visual acuity test to measure vision at a distance
- perform a dilated pupil examination to see the inside of the eye with
an ophthalmoscope to check for drusen (tiny yellow deposits on the
retina which are the most common early signs of AMD)
- ask the patient to look at an Amsler grid
with a pattern of straight
horizontal and vertical lines. To the person with AMD, the lines appear
wavy, distorted or missing or a black spot may appear in the center of
the grid.
- perform a fluorescein angiography. During this test, a dye is
injected into the arm and quickly travels throughout the blood system.
Once the dye reaches the blood vessels in the back of the eye,
photographs are taken of the eye. The dye allows the ophthalmologist to
detect blood vessels that are abnormal and leaking dye.
What are the current treatment options for macular degeneration?
Bascom Palmer Eye Institute’s faculty has led the way in every treatment for the wet form of age-related macular degeneration (AMD). Various treatments are currently available and offer promise for the wet form, the more devastating form of AMD and the leading cause of blindness in people over age 50 in developed countries. Vision improvement is only possible if the wet form of AMD is treated at an early stage. If vision loss has been long standing and if there is no evidence of blood vessels growing and leaking in the eye, then these treatments are unlikely to result in any vision improvement.
Regardless of the treatment therapy followed, patients with advanced dry macular degeneration should check the vision in each eye, one at a time, at least once a day. By staring at the central point on an
Amsler grid,
patients can help monitor their vision regularly and can detect distortions in vision. These distortions represent the earliest stages of wet macular degeneration.
Pegaptanib (Macugen). Retina specialists from Bascom Palmer Eye Institute participated in international clinical trials which led to the FDA approval of Macugen to treat the wet form of AMD. Macugen was the first approved treatment that targeted the vascular endothelial growth factor (VEGF). Patients with wet AMD have high levels of VEGF protein in their affected eyes. VEGF is a protein that
causes the abnormal blood vessels to grow, leak, bleed and damage a part of the retina known as the macula resulting in loss of central vision that prevents driving, reading, recognizing people, and other important tasks that contribute to a high quality of life. Studies published in the New England Journal of Medicine showed that inhibition of the VEGF protein by Macugen was able to prevent the growth of these abnormal blood vessels and preserve vision. However, most patients continued to lose some vision even if they received Macugen.
Bevacizumab (Avastin). Bascom Palmer retina specialist Philip Rosenfeld, M.D., Ph.D. pioneered the off-label use of Avastin to treat the wet form of AMD. Now used by retina specialists throughout the world for its effectiveness and economical advantage over other treatments, Avastin was the first treatment in clinical practice that had the potential not only to stop further deterioration in vision from wet AMD, but bring about significant improvement in vision for patients with wet AMD. Avastin is currently approved by the FDA for the treatment of metastatic colorectal cancer. In Bascom Palmer’s clinical experience, the results which were published in the journals Ophthalmology and Retina, significant vision
improvement was observed in over 35% of patients treated with Avastin and some improvement could be seen within only one week of treatment.
Ranibizumab (Lucentis). In June 2006, the U.S. Food and Drug Administration (FDA) approved Lucentis for the treatment of the wet form of AMD. Like Macugen and Avastin, Lucentis is injected directly into the eye. Lucentis and Avastin are both manufactured by Genentech, Inc. and both are derived from the same monoclonal antibody against VEGF. Lucentis was engineered specifically for the eye and tested in rigorous Phase III trials. Lucentis is a smaller molecule that was designed to have better penetration into the retina. Like Avastin, Lucentis can improve visual acuity with over 35% of patients experiencing significant improvement. Bascom Palmer Eye Institute was involved in every clinical phase of Lucentis development. Rosenfeld was a principal investigator and is first author on publications from the Phase I, Phase II, and Phase III trails that resulted in FDA approval for Lucentis. Lucentis is now
commercially available and the firstline therapy for those patients able to afford the treatment.
The proper treatment for the wet form of age-related macular degeneration is best determined by a retina specialist after thorough examination of the eyes.
Despite all these advances to treat the wet form of AMD, we still do not have effective therapies for the vast majority of patients with dry AMD. For this reason, the best option for many of our patients is to receive low vision training. Whether it is vision loss for conditions such as AMD, glaucoma or diabetes, low vision aids help patients perform normal activities of daily living and lead independent lives. To help facilitate this training, Bascom Palmer Eye Institute has a Low Vision Center to assess patients' remaining vision and prescribe appropriate low vision aids.
Do vitamins have an impact on the development of macular degeneration?
The National Eye Institute, one of the federal governments National Institutes of Health,
sponsored a major clinical trial called the Age-Related Eye Disease Study whose results were
published in the October 2001 issue of Archives of Ophthalmology. Scientists found that high
levels of antioxidants and zinc may reduce the risk of losing vision in the future from
age-related macular degeneration. Click here for greater details, including the dosage
formulation and information for smokers.
What about macular degeneration research?
Much work needs to be done to slow the progression of both dry
and wet AMD, and even restore vision in patients with this disease.
All of our treatments, so far, are designed to treat the vision loss associated with wet AMD and slow the progression of the disease. None of the therapies really treat the underlying cause of AMD. While we do not yet know the cause, we do know this is a disease with a strong genetic basis. For this reason, Bascom Palmer Eye Institute is trying to find the genes responsible for AMD in the hope of someday developing a cure. To achieve this goal, we need the help of any family where one or more family member is affected with AMD. We are years away from developing a successful therapy based on genetic information, but the basis for this therapy begins with the genetic research currently underway and the help of families with AMD
What is a macular hole?
 As people age, the vitreous gel in the eye shrinks and pulls away from
the retina. Usually this occurs without consequence, however, in some
cases where the vitreous is attached to the macula, it can result in the
formation of a macular hole. Fluid may leak under the edges of the hole,
causing a microscopic retinal detachment, which results in blurring and
distortion of vision.
What are the symptoms of a macular hole?
A macular hole can cause blurred or distorted vision. A hole that goes
all the way through the macula can result in significant loss of central
vision.
How is a macular hole diagnosed?
An ophthalmologists who suspects a macular hole may:
- perform a visual acuity test to measure vision at a distance
- perform a dilated pupil examination to see the inside of the eye with
an ophthalmoscope
- perform a fluorescein angiography. During this test, a dye is
injected into the arm and quickly travels throughout the blood system.
Once the dye reaches the blood vessels under the retina, a color
photograph is taken of the eye. The dye allows the ophthalmologist to
detect blood vessels that are leaking dye.
What are the treatment options for a patient with a macular hole?
Current treatment options for macular holes are limited to vitrectomy
with an internal tamponade. The most commonly used procedure involves
using a long-acting gas. During the surgery, the ophthalmologist will
remove the vitreous gel from the eye so that it is no longer pulling on
and distorting the macula. The vitreous gel is replaced with a bubble
containing a mixture of air and gas or even silicone oil can be used. The
long-acting gas acts as an internal, temporary bandage that holds the edge
of the macular hole in place as it heals, though it prohibits the patient
from traveling by air for at least six weeks. Under extenuating
circumstances a shorter acting gas or the silicone can be used to possibly
reduce or eliminate the prohibition of air travel. They physicians at
Bascom Palmer believe the shorter acting gas and silicone oil do not offer
quite as high success rates, but they are substantially successful. In
order to maximize the effect of the repair, the patient is usually
required to remain in a face down position for one week postoperatively to
allow the bubble to press against the macula and seal the hole. While
Bascom Palmer physicians believe that strict, continuous positioning
enhances success rates, substantially high rates are obtained even in
patients who are unable to maintain this position. The bubble will
gradually be reabsorbed by the eye within a few weeks following surgery.
As the bubble is reabsorbed, the vitreous cavity refills with a naturally
produced fluid.
Currently, it is customary to peel the internal limiting membrane during
surgery, as this may remove an impediment to healing the hole, and
possibly even stimulate healing. This issue is controversial and studies
of its efficacy are ongoing.
What advantage does Bascom Palmer offer for patients with a macular hole?
Bascom Palmer Eye Institute surgeons were among the first to perform
macular hole surgery, dating back to 1991. Much of the framework of
knowledge of pathogenesis, diagnostic methodology, and classification was
laid at this institute. Because of this early experience, we continue to
perform treatment on a high volume of patients. This allows us to make
observations and conclusions regarding the most effective treatment
modifications relatively rapidly.
What research in being conducted in the United States and at Bascom
Palmer Eye Institute on macular holes?
Research is currently aimed at efforts to improve the 90+% success rate
even more, and in a more convenient way to the patient. This is through
ongoing surveillance of success in clinical series. Bascom Palmer Eye
Institute conducts such series similarly to many other study centers in
the country.
Who are the Macular
Specialists at Bascom Palmer Eye Institute?
Thomas Albini, M.D.
John G. Clarkson, M.D.
Janet L. Davis, M.D.
Sander Dubovy, M.D.
Harry W. Flynn, Jr., M.D.
Jaclyn L. Kovach, M.D.
Geeta Lalwani, M.D.
Wen-Hsiang Lee, M.D.
Andrew A. Moshfeghi, M.D.
Timothy G. Murray, M.D., M.B.A., F.A.C.S.
Philip J. Rosenfeld, M.D., Ph.D.
Stephen Schwartz, M.D., M.B.A.
William E. Smiddy, M.D.
Other Macular Disease Resources
AMD Alliance International
American Academy of Ophthalmology
Eye Resources on the Internet
Foundation Fighting Blindness
Macular Degeneration Partnership
National Eye Institute
Prevent Blindness America
Research to Prevent Blindness
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