Be Heart-Smart
When Treating the Eye
Christopher J. Quinn, O.D.
Read about "Coronary Heart Disease in the United
States"
What’s your first choice of therapy for treating primary open angle
glaucoma? If you’re thinking beta-blockers, you’re in good company. Today’s
standard-of-practice for optometrists is to use a non-selective beta-blocker
as the first line agent in the treatment of POAG.
This approach made perfect sense 15 years ago when we had only three
topical agents to treat glaucoma. The two other agents were pilocarpine
and epinephrine. Because of pilocarpine’s side effects and epinephrine’s
high rate of allergic reactions, beta-blockers were the obvious choice.
But today we have more choices. These choices give us the opportunity
and the responsibility to be more selective before prescribing a lifelong
term of therapy. One consideration that merits your attention is the effect
that beta-blockers—even topically applied—have on blood lipid levels.
True, studies and experience have shown that non-selective beta-blockers
are dependable and effective in decreasing intraocular pressure. Side effects
are well recognized, and careful patient selection can avoid most problems.
However, recent research has focused attention on beta-blockers’ ability
to alter a patient’s serum lipid profile. Specifically, topical application
of non-selective beta-blockers has been shown to reduce high-density lipoprotein
(HDL) cholesterol levels (the “good” cholesterol component) and increase
serum triglycerides. Decreased HDL and increased triglycerides can increase
the risk of coronary heart disease and atherosclerosis. It’s thought that
beta-blockers may alter blood lipid levels by inhibiting the enzyme lipoprotein
lipase.
Ten years ago, researchers first described the effect of topical timolol
0.5% on patients with glaucoma and ocular hypertension.1 They
found a statistically significant decrease in serum HDL and an increase
in serum triglycerides. These authors predicted this change in blood lipids
increased the risk of coronary artery disease by 21%.
The results have been confirmed in subsequent studies. Most recently,
a comparative study of the effect of non-selective beta-blockers on blood
lipid levels showed no significant difference between timolol maleate (Timoptic),
carteolol hydrochloride (Ocupress) and metipranolol (Optipranolol) in their
effect on blood lipid levels.2 This is significant since previous
studies had indicated a potential benefit in the use of carteolol in its
effect on blood lipid levels.
These studies prove one important thing: We need to consider the effect
of our treatment on the patient’s general health as well as the local effect
in reducing IOP. Long-term therapy, particularly in patients who have elevated
cholesterol or other significant risk factors for coronary artery disease,
may work better with an alternative agent as the initial treatment of choice.
Today’s alternatives—including alpha-agonists, prostaglandin analogs
and carbonic anhydrase inhibitors—all can be effective in reducing IOP
while not interfering with patients’ serum lipid levels.
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1.Coleman et al. Topical timolol decreases plasma high-density lipoprotein
cholesterol levels. Arch Ophthalmol 1990 Sep;108(9):1260-3.
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2. Mirza GE et al. Comparison of the effects of 0.5% timolol maleate, 2%
carteolol hydrochloride, and 0.3% metipranolol on intraocular pressure
and perimetry findings and evaluation of their ocular and systemic effects.
J Glaucoma 2000 Feb;9(1):45-50.
Coronary Heart Disease in the United States
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CHD is the leading killer of American men and women.
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12 million Americans have a history of heart attack and/or angina.
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Each year 1.1 million have heart attacks—370,000 die—250,000 die within
1 hour.
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By age 60, every fifth man and 17th woman develops CHD (1986 Framingham
data).
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1999 estimated direct and indirect costs of heart disease are $99.8 billion.
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