about 15% -- enough to cause 22,000 extra cataract cases in the U.S.
each year, Canadian researchers suggest.
The study does not prove that antidepressants cause cataracts. And even if
the finding is confirmed, the risk to an individual taking antidepressants is
But these widely prescribed drugs may pose a vision risk in elderly
patients, suggest Mahyar Etminan, PharmD, and colleagues of the University of
British Columbia, Vancouver, Canada.
"This study showed for the first time that SSRI use may be associated with
an increase in the risk of cataracts," Etminan and colleagues conclude.
The researchers analyzed data collected from 18,784 cataract patients and
187,840 comparison patients between 1995 and 2004. All of the patients had
heart disease and had undergone treatment for blocked arteries. Their average
age was 73.
Only patients currently using antidepressants -- not those who had taken
them in the past and stopped -- were at increased risk of cataracts. Even so,
only 8.5% of cataract patients in the study had taken SSRI antidepressants at
Not all SSRI antidepressants were found to increase cataract risk, although
this may be because not enough people in the study were taking them for the
researchers to detect a risk. Risk was found for three different
- Luvox raised cataract risk by 39%.
- Effexor raised cataract risk by 33%.
- Paxil raised cataract risk by 23%.
- Overall, use of any SSRI antidepressant raised cataract risk by 15%.
Assuming that 10% of Americans take SSRIs, that the increased risk is 15%,
and that 1.5% of cataracts in the U.S. are caused by antidepressants, the
researchers calculate that SSRIs may cause 22,000 extra cases of cataracts each
How Antidepressants Might Cause Cataracts
How could antidepressants cause cataracts?
SSRI antidepressants work by increasing the amount of serotonin in the
brain. (Effexor is not strictly an SSRI, as it boosts norepinephrine as well as
Etminan and colleagues note that the lens of the eye has serotonin receptors
-- switches that activate cellular functions. Animal studies show that
serotonin can make the lens of the eye more opaque and lead to cataracts.
If the Etminan findings are confirmed, SSRI antidepressants would not be the
first drug to increase cataract risk. Oral and inhaled steroids and
beta-blockers have also been linked to cataract formation.
The Etminan study appears in the March 7 online issue of
Ophthalmology. Pfizer, the maker of Effexor, and Abbott, the maker
of Luvox, were contacted for comment but were unable to reply in time
By Daniel DeNoon
Reviewed by Laura Martin
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