BUSINESS WIRE
Studies Among Highlights of March 2008 Issue of Ophthalmology
SAN FRANCISCO--(BUSINESS WIRE)--Are cataract rates on the decline? Should glaucoma patients seeking
alternative therapies trust what they find online? Are seatbelts still
important to protect eyes in auto accidents, now that most cars have
airbags? What’s the connection between hearing
loss and one form of glaucoma? These are among the topics explored in
the March 2008 issue of Ophthalmology, the journal of the
American Academy of Ophthalmology.
Are Cataract Rates Declining? Findings of the Beaver Dam Eye Study
The population-based Beaver Dam Eye Study was designed by Barbara E. K.
Klein, MD, MPH, and colleagues to determine through long-term
observation whether there were differences among age cohorts regarding
rates of cataract prevalence and surgery, as well as type of cataract.
Five-thousand residents of Beaver Dam, Wisconsin, were examined for the
three most common forms of cataract—nuclear,
cortical and posterior sub-capsular—at
baseline in 1990 and five, 10 and 15 years later. Results were analyzed
by age group and gender for this population, which was 99 percent white.
The rates of all three cataracts increased with age for all cohorts and
are described in the study in detail by age cohort and gender.
An interesting decline in prevalence of nuclear cataract—the
type characterized by hardening of the center of the eye’s
lens—was found when participants were
considered in five-year age and birth cohorts (excluding the 75+ group,
which had too few participants). Even after adjusting for expected
higher prevalence at older ages, the study found that prevalence
declined in each successive birth cohort. The authors suggested that
this decline may be related to negative health habits shared by people
in the older cohorts and to more positive health habits in the younger
cohorts. The researchers write: “Possible
protective exposures include a decrease in smoking and increase in
exposure to healthy lifestyle habits.” Rates
of cataract surgery also increased in the 15-year time period, as
surgical techniques and outcomes improved significantly and more people
elected cataract surgery at earlier points in the disease process.
Glaucoma Patients Seek Complementary and Alternative Therapies Online
About 117 million people in the United States use the internet to access
conventional and complementary/alternative medical (CAM) information.
Among glaucoma patients an estimated 5.4 percent use CAM therapies, and
many rely on the internet to learn about and purchase services and
products. A research team led by Dr. Daniel George Ezra assessed 21
high-traffic CAM-for-glaucoma web sites to determine the most
prevalently recommended therapies, the factual basis of the information
presented, and potential commercial bias. Only one site was approved by
the Health on the Net Foundation, the United Nations-accredited guide to
reliable online medical information, but the study judged 11 sites “excellent”
based on a standardized rating system. Thirteen sites were found to have
expressed opinions without factual substantiation, and two sites were
rated “high risk”
to patients because they discouraged using conventional medicine.
Fourteen sites offered products and/or services for purchase.
The most frequently recommended CAM therapies were: vitamin C; the herbs
forskolin and ginkgo biloba; and nutrients alpha-lipoic acid,
rutin/flavinoids, and vitamin E. The authors concluded: “Medical
information conveyed over the internet is of variable quality...Many
sources contain advice on therapies that have no evidence base and may
put patients at risk.” They encouraged
ophthalmologists to become aware of CAM-for-glaucoma internet content so
they can help patients make informed choices.
Seatbelts Reduce Eye Injury Risk in Auto Accidents
Although airbags in automobiles have helped reduce overall injuries and
fatalities by 32 percent since they were introduced in the 1970s, airbag
deployment sometimes causes eye injuries, with an estimated incidence of
5 percent. A 2007 study led by Sunil K. Rao, MD, evaluated how seatbelt
use correlated with eye injuries and the recovery of visual acuity in
auto accidents where airbags deployed. The study concluded that “the
use of seatbelts was associated with less severe ocular injuries and
better visual outcomes.” Reviewing medical
records of the Rhode Island Hospitals general eye clinic January 1997 to
August 2005, researchers selected 47 patients who were either the driver
or front-seat passenger in an auto accident with airbag deployment,
excluding accidents with rollover or ejection. Patients had been
questioned by clinic staff regarding seatbelt use, eyewear use, and
airbag status.
Injuries were ranked as mild, moderate, or severe using a standardized
scale: 49 percent of the patients had severe injuries, 23 percent
moderate, 26 percent mild, and 2 percent were not injured. Seventy-one
percent of those not restrained by seatbelts had severe injuries versus
31 percent wearing seatbelts. Forty-two percent of restrained patients
had only minor injuries. Visual acuity outcomes also depended on
seatbelt status, with unrestrained patients significantly more likely
than restrained to have 20/200 or worse vision at the three month
post-accident follow-up. None of the patients was wearing eyeglasses,
and none had previously had cornea transplant or refractive surgery;
these variables could influence results in future studies. The patients'
age, gender, accident type and alcohol status were not significantly
related to injury severity.
An Eye Disease or Systemic Disorder? Hearing Loss Study Adds to the
Evidence
Shahin Yazdani, MD, and his research team evaluated whether patients
with ocular pseudoexfoliation syndrome—the
most common cause worldwide of the form of glaucoma known as “secondary
open angle”—had a
higher incidence of hearing loss. In ocular pseudoexfoliation (also
called “exfoliation”)
syndrome, fibrous white deposits aggregate on the iris, lens and other
parts of the eye and can block fluid drainage; this blockage increases
intraocular pressure, which can damage the optic nerve. Similar
fibrillar deposits have been found in the heart, blood vessels, lung,
liver, kidneys and skin of patients with ocular pseudoexfoliation. In
addition, pseudoexfoliation has been associated with ischemic heart
disease, systemic hypertension, aneurysms, Alzheimer’s
disease, and age-related macular degeneration (AMD). The researchers
hypothesized that the hearing organs might also be affected after
noticing hearing disability in many pseudoexfoliation patients.
The case-control study enrolled 83 patients with ocular
pseudoexfoliation and 83 controls matched for age and gender. Hearing
loss was significantly more prevalent in patients with pseudoexfoliation
than controls—94 percent versus 69.9 percent.
Below-average hearing thresholds were also significantly more common in
ears of cases versus controls, 88.4 percent and 53.6 percent
respectively. As in past studies, no definitive correlation was found
between glaucoma and hearing loss. The authors conclude: “The
findings of the present study imply that this apparently ocular disorder
may truly be a manifestation of a systemic condition that affects
multiple organs throughout the body.”
Ophthalmologists are urged to consider the possibility of hearing loss
in patients with ocular pseudoexfoliation syndrome and guide them to
additional medical care as needed.
Eds: Full texts of the studies are available from the Academy’s
media relations department.
Broadcast eds: AMD B-roll footage is available from the Academy.
Please contact the Academy's media relations department for download
information.
About the American Academy of Ophthalmology
The American Academy of Ophthalmology is the world's largest association
of eye physicians and surgeons—Eye M.D.s—with
more than 27,000 members worldwide. Eye health care is provided by the
three “O’s”
– opticians, optometrists and
ophthalmologists. It is the ophthalmologist, or Eye M.D., who can treat
it all: eye diseases and injuries, and perform eye surgery. To find an
Eye M.D. in your area, visit the Academy's Web site at www.aao.org.