Other Diseases and Glaucoma
Chat Highlights
September 7, 2005

On Wednesday, September 7, 2005, Dr. Elliot Werner a glaucoma specialist at Wills, and the glaucoma chat group discussed "Other Diseases and Glaucoma."

Moderator:  Welcome, Dr. Werner. Several people have asked for a discussion of other diseases and glaucoma.  Let's start with age-related macular degeneration (AMD).  Is there a relationship between AMD and glaucoma?

Dr. Elliot Werner:  Probably not, but both are common in older people, so we often see them in the same patient.  They have different underlying causes and mechanisms, so they are probably unrelated.  Glaucoma, for example, is more common in African-Americans.  AMD is more common in whites, and is the leading cause of blindness in the United States and many European countries.

Moderator:  Isn't AMD more common in older people?

Dr. Elliot Werner:  Yes, AMD is a common cause of vision loss in older people.  *Macular degeneration affects the retina in the center, the macular, the part that is responsible for our best vision.  The cells of the retina die due to abnormal circulation, and result in loss of central vision.

P:  What is the treatment for a glaucoma patient who has AMD?

Dr. Elliot Werner:  AMD does not have any really good treatments.  Recent advances include phototherapy and Macugen, which is a drug that is injected directly into the eye to inhibit the progress of macular degeneration.  If someone has both diseases, each disease would be treated more or less independently of the other.

P:  How high are the risks of a retinal tear from injecting Macugen into the eye?  I assume the risk would be the same as with any other type of injection into the eye.

Dr. Elliot Werner:  I'm not sure, but with all the Macugen being used now, the incidence of retinal tears or detachments must be very low since you hardly ever hear of them.  Infection is probably a greater risk from the injection.

P:  What is the difference between the wet and dry forms of macular degeneration?

Dr. Elliot Werner:  Wet AMD has bleeding or hemorrhaging in the retina. Dry AMD does not.  The dry form can progress to the wet form.  The wet form is worse and more destructive of vision.  The neovascular wet form of the disease is responsible for most (90%) of the severe loss of vision.

P:  What are the first signs of macular degeneration?

Dr. Elliot Werner:  Distortion of vision and blurring, especially for tasks requiring fine central vision, such as reading.

P:  Are glaucoma patients more likely to have macular degeneration in their lifetime, and are macular degeneration patients more likely to have glaucoma?

Dr. Elliot Werner:  Probably not.  The two diseases are largely independent.

P:  How often does dry macular degeneration become wet macular degeneration?

Dr. Elliot Werner:  Not often.  Most AMD is dry and remains dry.  Dry AMD is characterized by slow loss of vision that varies in severity from person to person.  Wet AMD is usually characterized by more rapid and profound loss of central vision.

P:  It's said that a diet rich in green vegetables can help AMD.  By the time a person is diagnosed with AMD, isn't it too late to try that approach?

Dr. Elliot Werner:  Certain dark green veggies, such as spinach, contain lutein. Lutein has been shown to reduce the risk of AMD and to slow its progress.  It's usually easier and more effective to take the lutein as a dietary supplement, but it is effective in early AMD as well as a preventive.

Moderator:  Wasn't there a pretty definitive study showing that supplements high in anti-oxidants do slow the progression of dry macular degeneration significantly?

Dr. Elliot Werner:  True, there are some commercially available vitamin supplements that contain lutein and the other antioxidants shown to be useful in slowing the development of AMD. **

[Editor's Note:  The formulation used in the AREDS was supplied by Bausch & Lomb Pharmaceuticals. Bausch & Lomb's product is marketed as PreserVision and is widely available in most all pharmacies.]

P:  Are drusen indicative of AMD?

Dr. Elliot Werner:  Drusen are little spots that appear in the retina.  They represent degenerative deposits in the retina and are a sign of early macular degeneration, but not everyone with drusen develops significant vision loss.

P:  Is AMD or glaucoma more likely to cause loss of sight?

Dr. Elliot Werner:  Significant loss of functional vision is probably more likely in AMD than in glaucoma.  In North America, AMD is a more prevalent cause of visual disability than glaucoma in the white population.

P:  What are the concerns for glaucoma patients who also have macular degeneration?

Dr. Elliot Werner:  The concern is that they have two potentially blinding diseases.

P:  Is macular degeneration passed down from one generation to the next?

Dr. Elliot Werner:  That's hard to say, because the patients are usually old, and it is hard to get good family histories, but many cases of AMD seem to be hereditary.  Exposure to sunlight during life is another important cause of AMD.

Moderator:  What is diabetes and is it more common in people with glaucoma?

Dr. Elliot Werner:  Diabetes is a disease characterized by an inability of the body to properly metabolize sugar.  Whether or not glaucoma is more common in diabetics is somewhat controversial.  Most recent evidence suggests that it is not, but again, you've got two very common diseases that often co-exist in the same patient.

P:  Is a person with diabetes more likely to get glaucoma?

Dr. Elliot Werner:  The evidence in the medical journals is contradictory on that one, so no one really knows.  A certain severe form of secondary glaucoma, called neovascular glaucoma, is found in patients with severe diabetic retinopathy.

P:  Is a person with glaucoma more likely to get diabetes?

Dr. Elliot Werner:  Probably not. The relationship doesn't seem to go the other way.

P:  Can diabetes be detected even in someone taking Cosopt, which I thought I read can mask the results?  I consume a lot of sugar, which I hear can make my system get out of whack.

Dr. Elliot Werner:  Beta blockers can alter sugar metabolism and make detecting and managing diabetes a bit more problematical, but modern techniques and good internists know that and can work around it.

P:  Because I have ICE (irido corneal endothelial syndrome) and glaucoma, I always think that the two go together.  Do most ICE patients get glaucoma?

Dr. Elliot Werner:  Yes, most ICE patients develop a form of glaucoma.  Glaucoma is one of the cardinal features of ICE syndrome, not a separate disease.

P:  Is there any new research on the relationships between herpetic viruses and ICE syndrome?

Dr. Elliot Werner:  I am aware of only one study done about 20 years ago showing a relationship.  Subsequent research has not confirmed that.  Most researchers working in the field are skeptical.

P:  Do you see any correlation between the age that an ICE patient's symptoms begin and the aggressiveness of the disease?  I mean, if the patient is young, is ICE more aggressive?

Dr. Elliot Werner:  Only to the extent that ICE tends to progress over time, so the younger the patients, the longer they will live and have ICE.

P:  Do you have any idea of why ICE advances?  I know it doesn't start until the 30 to 50 age range, but I'm wondering whether environmental or health problems are a factor in bringing it on earlier.

Dr. Elliot Werner:  ICE is a great mystery.  No one knows the answers to your questions.

P:  I know there are not many answers to questions about ICE, which is probably one of the most frustrating parts of the disease.  My understanding is that ICE is rare enough not to be studied or researched.  Would you say that's true?

Dr. Elliot Werner:  There is a fair amount of information about ICE in the literature, but it is mostly the pathology of the condition and the response to various treatments.  The kind of epidemiological (i.e., that which deals with the incidence, distribution, and control of disease in a population) information you want is not available and difficult to come by.

P:  Is a person with high blood pressure or heart disease more likely to get glaucoma?

Dr. Elliot Werner:  That's another controversial question.  There is some evidence that people with vascular diseases are more likely to get normal-tension glaucoma (NTG), but not primary open-angle glaucoma (POAG).

P:  Does hypothyroidism (underactive thyroid) have a bearing on the development of glaucoma?

Dr. Elliot Werner:  Hypothyroidism probably does not.  Again, however, there is some evidence that hypothyroidism is associated with glaucoma.  One of the problems here is that older people tend to have a number of things wrong with them.  It is often very difficult to sort out what is related and what is just coincidence.  By the way, the five major risk factors for glaucoma are intraocular pressure, age, race, myopia, and family history.

P:  Why do some people with myopia develop glaucoma?

Dr. Elliot Werner:  The reason is not completely understood, but probably has to do with an underlying abnormality of the structural proteins of the eye that affect its growth and development.

P:  How myopic do you have to be for myopia to be considered a risk factor?

Dr. Elliot Werner:  Generally, more than -5, but any degree of myopia has a small effect on risk.

P:  I have NTG and my father had glaucoma.  I have three near-sighted (myopic) nephews in their 30s, and all have had LASIK.  Am I being an alarmist in urging them to have a dilated eye exam?  Their mothers, my sisters, do not have glaucoma.

Dr. Elliot Werner:  No, you are being very sensible.  You should continue to urge these high-risk nephews to be checked regularly.

P:  Would untreated high blood pressure contribute to the progression of glaucoma even if it might not have caused it in the first place?

Dr. Elliot Werner:  It might by causing poor circulation and ministrokes, but, again, the evidence is not very strong.

P:  Inflammation in the body seems to be a cause of many woes, such as arthritis. Does inflammation also aggravate glaucoma?

Dr. Elliot Werner:  Ocular inflammation, such as scleritis or uveitis, can cause a form of glaucoma.  There is some evidence that patients with NTG have abnormal inflammatory responses and autoimmune reactions.  Garden variety POAG does not seem to be related to inflammation.

P:  What are some examples of abnormal inflammatory responses and autoimmune reactions?

Dr. Elliot Werner:  Mostly, those are laboratory studies done on the blood and white blood cells of these patients.  The clinical significance of this is unknown.  For example, there is an increase in what are called heat shock proteins in NTG patients.

P:  What kinds of vascular disease are associated with NTG?

Dr. Elliot Werner:  Small vessel disease, such as arteriosclerosis and strokes.

P:  Because of Hurricane Katrina, many glaucoma patients are lacking their glaucoma medication.  Besides the risk of intraocular pressures rising to dangerous levels, isn't there also a greater chance of eye infections in those who have trabeculectomies and got that fetid water in their eyes?

Dr. Elliot Werner:  Yes. I'm sure the health effects -- ocular, physical and psychological -- of this disaster will be profound.

P:  I have glaucoma related to juvenile rheumatoid arthritis (JRA).  I have taken my two sons for full eye exams.  The last time, the ophthalmologist did not feel it was necessary to check the intraocular pressure of my nine year old son or put him through the stress.  With my eye history, should I insist on having his pressure checked?

Dr. Elliot Werner:  The intraocular pressure can be measured in most nine year olds with a little coaxing and parental cooperation.  I would have at least tried to measure the IOP.

Moderator:  Thanks so much, Dr. Werner. It's always a pleasure to have you with us.

Dr. Elliot Werner:  So long. I've enjoyed this evening.

[Editor's Notes]

*The average age of patients with the wet form of macular degeneration, which is responsible for most of the severe loss of vision, is in the mid-seventies, and rarely occurs before the age of 50. (See: http://www.macular-degeneration.org/theamster.htm )

** The Age-Related Eye Disease Study (AREDS) - sponsored by the Federal government's National Eye Institute - has found that taking high levels of antioxidants and zinc can reduce the risk of developing advanced age-related macular degeneration (AMD) by about 25 percent. (See: http://www.macular-degeneration.org/theamster.htm )

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