Eye Drops May Delay or Prevent Glaucoma in African Americans at Higher Risk
Eye drops that reduce elevated pressure inside the eye can delay
or possibly prevent the onset of glaucoma in African Americans at
higher risk for developing the disease, researchers have found.
This makes it more important to identify African Americans at higher
risk for developing glaucoma so they can receive prompt evaluation
for possible medical treatment. These results are reported in the
June 2004 issue of Archives of Ophthalmology.
Scientists found that daily pressure-lowering eye drops reduced
the development of primary open-angle glaucoma in African Americans
by almost 50 percent. Primary open-angle glaucoma is the most common
form of glaucoma and one of the nation's leading causes of vision
loss. Of the African American study participants who received the
eye drops, 8.4 percent developed glaucoma. By comparison, 16.1 percent
of the African American study participants who did not receive the
eye drops developed glaucoma. The study was funded by the National
Eye Institute (NEI) and the National Center on Minority Health and
Health Disparities (NCMHD), two components of the Federal government's
National Institutes of Health.
The results of this study, called the Ocular Hypertension Treatment
Study (OHTS), are a followup to initial results released two years
ago. In those findings, researchers discovered that treating people
with elevated eye pressure could delay or prevent the onset of glaucoma.
At that time, results for the subgroup of African Americans trended
in the same direction, but were not conclusive.
Primary open-angle glaucoma affects about 2.2 million Americans
age 40 and over, half of whom are not aware they have the disease.
Vision loss from glaucoma occurs when the optic nerve is damaged.
In most cases, elevated eye pressure, also called ocular hypertension,
contributes to this damage. This causes gradual loss of peripheral
(side) vision. As the disease progresses, the field of vision gradually
narrows and blindness can result. Glaucoma has no early symptoms,
and by the time people experience problems with their vision, they
usually have a significant amount of optic nerve damage. However,
if detected early, glaucoma can usually be controlled and serious
vision loss prevented. Comprehensive dilated eye examinations are
recommended at least once every two years for African Americans
over age 40 and all people over age 60.
"This is the first study to recruit large numbers of African
Americans to examine the benefit of pressure-lowering eye drops
to prevent or delay the onset of glaucoma," said Paul A. Sieving,
M.D., Ph.D., director of the NEI. "The results underscore that
African Americans over age 40 should receive a comprehensive dilated
eye exam at least once every two years to see if they are at higher
risk for glaucoma."
These results do not imply that every African American with high
eye pressure requires treatment, according to Eve Higginbotham,
M.D., chair of the Department of Ophthalmology at the University
of Maryland Medical Center and first author of the journal article.
"When determining treatment, doctors should take into account
several risk factors, including specific anatomical characteristics
of the optic nerve and the cornea," Dr. Higginbotham said.
"While African Americans participating in the study were more
likely than others to have these specific physical characteristics,
the study results underscore the importance of measuring these ocular
risk factors rather than relying solely on the race or ethnicity
of the individual."
Dr. Higginbotham suggested that before determining treatment, the
doctor and patient should also discuss the patient's health status
and life expectancy, and the burden of daily treatment, including
cost, inconvenience, and possible side effects.
Elevated eye pressure results when the fluid that flows in and
out of the eye drains too slowly, gradually increasing pressure
inside the eye. It is estimated that between three and six million
people in the U.S. are at increased risk for developing primary
open-angle glaucoma, representing between four and seven percent
of the population above age 40. In this study, ocular hypertension
was defined as pressure of 24 mm Hg or greater in at least one eye.
The OHTS studied more than 1600 people, including 408 African Americans,
40-80 years of age who had elevated eye pressure but no signs of
glaucoma. Half were assigned daily pressure-lowering eye drops,
and the other half were assigned to observation (no medication).
In the medication group, the number of African Americans participants
developing glaucoma was significantly lower (8.4 percent) compared
to the observation group (16.1 percent).
"The study also confirms that the risk for developing glaucoma
is higher among African Americans compared with others," said
Michael Kass, M.D., of the Washington University Department of Ophthalmology
and Visual Sciences and chair of the study. "A number of risk
factors may be contributing to the increased prevalence of visual
impairment from glaucoma in African Americans. These include a family
history of glaucoma; earlier onset of the disease compared to other
races; later detection of the disease; and economic and social barriers
Glaucoma is a leading cause of blindness in African Americans,
said John Ruffin Ph.D., director of the NCMHD. "Glaucoma is
almost three times as common in African Americans than Whites,"
Dr. Ruffin said. "However, if glaucoma is detected and treated
early in its progression, it can usually be slowed and serious vision
loss can be delayed."
Dr. Ruffin said Medicare covers an annual dilated eye examination
for people at higher risk for glaucoma. This important preventive
benefit defines higher risk as people with diabetes; those with
a family history of glaucoma; and African Americans aged 50 and
In addition to support from the NEI and NCMHD, the Ocular Hypertension
Treatment Study was supported by Research to Prevent Blindness and
Merck Research Laboratories. The study was conducted at 22 clinical
centers across the country. A list of study centers and principal
investigators is attached.
The National Eye Institute (NEI), the Federal government's lead
agency for vision research, is part of the National Institutes of
Health (NIH) under the U.S. Department of Health and Human Services.
NEI-supported research leads to sight-saving treatments and plays
a key role in reducing visual impairment and blindness.
The NIH's National Center on Minority Health and Health Disparities
(NCMHD) conducts and supports research, training, information dissemination
and other programs aimed at reducing the disproportionately high
incidence and prevalence of disease, burden of illness, and mortality
experienced by certain American populations, including racial and
ethnic minorities and other groups with disparate health status,
such as the urban and rural poor.
Attachment 1: Background:
Ocular Hypertension Treatment Study (African-American Results)
Attachment 2: Ocular
Hypertension Treatment Study: Current Principal Investigators & Study