Adjunct Professor, Glaucoma,
Molecular Pharmacology
Glaucoma, one leading cause of
blindness in the United States and other industrialized
countries, affects almost 3 million Americans. Eighty
thousands of these individuals are legally blind. Though
a traditional diagnosis of glaucoma includes the measurement
of eye pressure, ophthalmologists now know that eye pressure
taken during an office visit is not an accurate indicator
of the disease. John H.K. Liu, Ph.D., Adjunct Professor
of Ophthalmology and Director of the Glaucoma Molecular
Pharmacology Laboratory at the Shiley Eye Center, has
proposed, “Perhaps, the nighttime eye pressure,
not the office eye pressure, is a better indicator for
evaluating the risk for glaucoma."
This innovative idea is derived from his research
at both UCSD and earlier as a faculty member at Harvard
Medical School. The research, now in its seventh year, studies
the nighttime eye pressure in glaucoma patients and determines
which anti-glaucoma eye drops work best at night as well
as during the day. The time influence of the 24-hour day
is being systematically investigated under highly controlled
laboratory conditions. Contrary to previous ideas, Dr. Liu
is able to demonstrate that more than ninety percent of
the ‘healthy’ eyes register their highest pressure
at night. In glaucoma patients, eye pressure is found to
be always higher than the normal level at night and during
the day.
The
24-hour recordings of eye pressure are obtained in a state-of-the-art
sleep laboratory located at the Stein Clinical Research
Building on the UCSD campus. Patients typically spend one
weekend in the laboratory and have their eye pressure and
cardiovascular parameters measured every two hours. At night,
researchers may use sophisticated night vision devices to
perform the measurements in a totally dark environment.
According to the data, various anti-glaucoma medications
show different potencies at nighttime in lowering eye pressure.
How eye pressure and other physiologic parameters change
over the 24 hours are important new information which can
help eye doctors better diagnose and treat glaucoma.
Current patient participants
fall into several ongoing research projects: glaucoma patients
on various medications, glaucoma suspects, and individuals
with high office eye pressure for years, but who have not
developed glaucoma. A new project to investigate whether
sleep apnea (breathing stops periodically during sleep)
could be a warning sign of developing glaucoma was launched
in early 2003.
