Seeing Double? A Type of Antibiotic May be the Cause

09/04/09  Portland, Ore.

A 2009 study finds that a class of antibiotics known as fluoroquinolones, administered systemically to treat a broad range of bacterial infections, may cause double vision (diplopia) in some patients.

Researchers at the Oregon Health & Science University Casey Eye Institute launched the first investigation of this problem after the National Registry of Drug-Induced Ocular Side Effects at OHSU received multiple reports of diplopia associated with systemic fluoroquinolones. This antibiotic type has side effects not seen with other antibiotics, including tendon dysfunction, and it is possible that tendinitis in the muscles around the eyes could cause double vision. Fluoroquinolones treat infections including bacterial or chronic bronchitis, pneumonia, sinusitis, and some skin infections.

The results were published in the September issue of Ophthalmology, the journal of the American Academy of Ophthalmology.

The researchers, led by Frederick W. Fraunfelder, M.D., associate professor of ophthalmology in the OHSU School of Medicine, found 171 cases between 1986 and 2009 of fluoroquinolone use associated with double vision through a review of reports from the Food and Drug Administration, World Health Organization, and the National Registry of Drug-Induced Ocular Side Effects. The median patient age was 51.6 years, medication doses were within recommended levels, and the interval from starting medication to onset of double vision was 9.6 days on average.  Medication was discontinued in 53 patients, and diplopia resolved in all cases.

"Doctors need to be aware of this potential reaction when prescribing these antibiotics and consider stopping therapy if diplopia occurs," Dr. Fraunfelder said. He also said that special care should be taken with patients who are older than 60, have had renal failure, or are taking steroids, and that thorough ophthalmic and neurological exams should be done to rule out other causes of double vision.

About OHSU                          

Oregon Health & Science University is the state's only health and research university, and Oregon's only academic health center. OHSU is Portland's largest employer and the fourth largest in Oregon (excluding government). OHSU's size contributes to its ability to provide many services and community support activities not found anywhere else in the state. It serves patients from every corner of the state, and is a conduit for learning for more than 3,400 students and trainees. OHSU is the source of more than 200 community outreach programs that bring health and education services to every county in the state.

About the American Academy of Ophthalmology

AAO 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