Glaucoma Around the World

Chat Highlights
February 2, 2005

Norma Devine, Editor

On Wednesday, February 2, 2005, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Glaucoma Around the World."

Moderator:  The topic tonight is "Glaucoma around the World."

P:  Dr. Wilson, what are some of the differences in the prevalence and types of glaucoma around the world?

Dr. Rick Wilson:  Compared to Caucasians in America and Europe, African-Americans have three times the risk of glaucoma.  Africans have four times the risk.  Most of that glaucoma is primary open- angle, but there is about the same amount of angle-closure glaucoma in the two groups.  In China, the proportion of angle-closure glaucoma to open-angle glaucoma is just the opposite of what we see in America.  The Japanese have more normal-tension glaucoma than open-angle glaucoma.  The Inuit in Alaska and Greenland have high rates of angle-closure glaucoma.

P:  Do Scandinavians have a higher incidence of pigment-dispersion glaucoma?

Dr. Rick Wilson:  The Scandinavians have a higher proportion of pseudoexfoliative glaucoma.  Pseudoexfoliation is also prevalent among Mongolians, South African blacks, and Mediterranean peoples.

P:  Are the differences in glaucoma around the world based on race, geography, socio-economics, or other factors?

Dr. Rick Wilson:  The different kinds of glaucoma are based on race, whereas the severity often has to do with access to care, education, and other socio-economic issues.  Angle-closure glaucoma causes more blindness than open-angle glaucoma because it usually leads to higher pressures and faster damage.

P:  Are these differences among ethnic groups statistically significant?

Dr. Rick Wilson:  Yes, very much so.  African-Americans are 14 to 17 times more likely than Caucasians to go blind from glaucoma between the ages of 45 and 65.

P:  During a chat in November 2003, you said that many patients in India with angle-closure glaucoma are treated as if they had open-angle glaucoma, because the doctor did not gonioscope them or was unable to do so.  Does that also happen in China and Japan?

Dr. Rick Wilson:  Yes.  I worked with ORBIS in Shenyang, China, for a week in September, and it was amazing how poorly they differentiated the treatments between open-angle and closed-angle glaucoma.  They grossly underutilized the quite adequate laser they had there for doing peripheral iridectomies.

P:  Do Africans in Africa have a higher rate of primary open-angle glaucoma at an earlier age?

Dr. Rick Wilson:  Yes.  As I just mentioned, the rate for African-Americans is three times greater than that for Caucasians, whereas the rate for Africans in Africa is four times greater.  Even African-Americans are usually diagnosed 10 years earlier than Caucasians.

P:  Are native Americans more like the Inuit?

Dr. Rick Wilson:  Although I have Indian blood through my Dad, I don't know the answer.  I would guess that American Indians are much more like Caucasians than the Inuit.

P:  Is there any geographical tendency for given types of glaucoma here in north America?

Dr. Rick Wilson:  All the tendencies seem to be racial rather than geographic.  Hispanics, for example, as compared with Caucasians, have an increased risk of glaucoma after age 60.

P:  Recently I read something about an increased incidence of glaucoma in California.  There's some speculation that may be due to long-term, heavy computer use. Any thoughts on that?

Dr. Rick Wilson:  I've never seen a single study that proved any deleterious effects of computer usage on the eyes.  Carpal tunnel syndrome, back problem, etc., but not real eye problems other than "eyestrain."

P:  My daughter had her DNA tested for the glaucoma gene.  The tests found a common type that is known to exist in Turkey and in people of English ancestry.  The other type was unknown.  Are there other regions with specific genetic traits for glaucoma?

Dr. Rick Wilson:  That is not my forte, but I think a gene indigenous to Hungary has been found.

P:  I seem to recall reading that among Scandinavians pseudoexfoliative glaucoma is not only the most prevalent form of glaucoma, but also has a high rate of occurrence.  If that is so, is there any connection with the significant rate of pernicious anemia (inability to process vitamin B-12) among Scandinavians?

Dr. Rick Wilson:  I've never heard that.  We still don't know the cause of pseudoexfoliation.  It is interesting in that it is a whole-body, basement-membrane disease, but only the eye seems to be significantly damaged by it.

P:  Do the tendencies tend to all be racial rather than geographic, except for pseudoexfoliation glaucoma?

Dr. Rick Wilson:  Pseudoexfoliation is not an exception.  If you look at the Scandinavians in Minnesota, they have a high rate like their ancestors, but live among other Caucasians with the normal rates of glaucoma and pseudoexfoliation.

P:  Could sunlight, pigmentation, and weather be factors?

Dr. Rick Wilson:  Pigmentation seems to be a factor in how different peoples respond to certain medications.  It also makes a difference in the severity of their scarring after surgery for glaucoma.

P:  What countries are contributing the most to the advancement of treatments for glaucoma?

Dr. Rick Wilson:  The U.S., England, and South Africa, which furnished the ophthalmologist who invented aqueous shunts (Anthony Molteno) and another who developed the Baerveldt shunt (George Baerveldt.) Israel is making strides in vaccination against glaucoma, and I expect great things regarding stem-cell research out of Singapore, Korea, England, and Israel.  Russia helped in the development of the intraocular lens (IOL) and refractive surgery.  Hans Goldmann from Switzerland invented the way we measure eye pressure (tonometer) and the visual field (perimeter), and Frans Fankhouser developed the Nd:YAG laser.

P:  What kind of vaccination against glaucoma are the Israelis working on?

Dr. Rick Wilson:  A vaccination that initiates an immune response that increases the patient's resistance to glaucoma damage.

P:  Nyogel/Nyolol Gel®, a glaucoma medication, is now being sold in Israel by Promedico.  The gel includes low concentrations of timolol, is applied once a day, and is said to remain effective for 24 hours.  Do you know if Nyogel will become available in the U.S., and if it is as effective as the prostaglandins?

Dr. Rick Wilson:  We have Timoptic XE and Timolol GFS , both of which develop or include a gel and last 24 hours, as does the newest beta-blocker, Istalol.  Beta-blockers are not as effective as prostaglandins as first-line therapy.

Moderator:  Thank you once again, Dr. Wilson.

Dr. Rick Wilson:  Everyone have a wonderful week.  Thanks for your attention.

End of highlights for Febuary 2, 2005.

On February 9, Dr. Wilson discussed "Glaucoma and Congenital Cataracts" in the Chat room. Click here for highlights of that meeting.

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