Race and Glaucoma
Chat Highlights
June 9, 2004

Norma Devine, Editor

On Wednesday, June 9, 2004, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Race and Glaucoma."

Moderator:  Dr. Wilson, is it known why blacks are more likely than whites to develop glaucoma, and why the prevalence of normal-tension glaucoma (NTG) is high among Japanese?  

Dr. Rick Wilson:  I think the concept is that different groups of people have different inherited characteristics that may predispose them to one type of glaucoma more than another.

P:  Are there any races that are rarely or never affected by glaucoma?

Dr. Rick Wilson:  Not that I can think of.  Certainly, open-angle glaucoma is less common in Chinese, but this lesser prevalence is balanced by the greater risk of angle-closure glaucoma in that group. The same would be true for the Inuit in Greenland.

P:  Which type of glaucoma seems to be race related?

Dr. Rick Wilson:  Angle-closure glaucoma is the type of glaucoma that is most race related.  The Inuit, more than the Chinese, more than the rest of us, have a higher rate of angle-closure glaucoma.  The Japanese are much more prone to normal-tension glaucoma (NTG).  Scandinavians and black South Africans are among the groups that are more prone to pseudoexfoliative glaucoma.

P:  Do treatments for glaucoma vary according to race?  For instance, does one race do better with lasers than with filtering surgery?

Dr. Rick Wilson:  According to one study, African-Americans do better with laser first, before surgery, whereas Caucasians do better going straight to trabeculectomy.

P:  Do second- and third-generation Japanese living in North America have the same rate of NTG as Japanese in Japan?

Dr. Rick Wilson:  I think so, but I'm not sure.

P:  In Japan, is the higher incidence of NTG there inherited or environmental (diet, etc.)?

Dr. Rick Wilson:  The tendency seems to be inherited.

P:  It is said that being an African-American is a risk factor for glaucoma.  Is being an African in Africa also a risk factor, outside of differences in screening and treatment opportunities?

Dr. Rick Wilson:  Absolutely.  I have been told by Nigerian ophthalmologists that 10% of Nigerians have glaucoma.  Of that 10%, 91% are unilaterally blind and 34% are bilaterally blind.  Glaucoma often occurs at a younger age in America and in Africa.

P:  Are the Nigerians blind because their glaucoma is particularly severe or because of lack of health care?

Dr. Rick Wilson:  Both.  When I was working in Ghana, it was not unusual for me to find people coming in for screening who had 5% of each nerve already destroyed, and IOPs in the upper 50's.  That would be unusual in America.

P:  Is the glaucoma gene test (Ocugene test) used much in screening populations in the U.S. and abroad?

Dr. Rick Wilson:  No, because it detects only a small proportion of those genetically prone to glaucoma.

P:  Being black is defined as a risk factor for glaucoma, but how is "black" defined in that context?

Dr. Rick Wilson:  The term is usually self-defined, and that is increasingly difficult to sort out.  Tiger Woods is a case in point.

P:  Is the long-term prognosis for glaucoma different for certain races or ethnicities?  

Dr. Rick Wilson:  African-Americans do less well with surgery.

P:  When conducting research, do you factor in race in all research?  Is there a certain number of blacks, whites, Hispanics, Asians, etc., in each study?

Dr. Rick Wilson:  We do try to obtain a representative sample when we do the studies.

P:  Do you do any research where just one group is tested? 

Dr. Rick Wilson:  I, personally, am not doing any now, but such research is done if there is a good control group with which to compare it.  

P:  Which racial groups have different characteristic glaucoma patterns?

Dr. Rick Wilson:  Just the ones I have mentioned:  Inuit, Chinese, Japanese, African-Americans.  Actually, older Hispanics have an increased prevalence of glaucoma, though the characteristics are a little different from those of Caucasians.

P:  Do certain races do better with certain eye medications?

Dr. Rick Wilson:  Thinner corneas allow more drug to enter the eye.   African-Americans, on average, have thinner corneas. The increased absorption of medication from drops, however, is counterbalanced in the case of beta-blockers by the thicker pigmented layer of the iris, which absorbs more of the medication.

P:  Do you know the outcome of the glaucoma study on the Caribbean island of St. Lucia? 

Dr. Rick Wilson:  Sixteen percent of those with untreated glaucoma ended up unilaterally blind over ten years.

P:  Why were they blind in only one eye?

Dr. Rick Wilson:  The researchers were measuring the time to blindness in one eye, which is obviously shorter than in two eyes.  That was just the end point of the study the researchers chose.  

Moderator:  Thank you, Dr. Wilson.

Dr. Rick Wilson:  You're welcome.  Goodnight, everyone.

End of highlights for June 9, 2004.

On June 16, Dr. Wilson discussed "Uveitis and Glaucoma" in the Chat room. Click here for highlights of that meeting.

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