Study Indicates Increase in
number of corneal ulcer cases!
number of corneal ulcer cases!
November 16, 2006 — A marked increase in incidence of fungal
and amoeba infections cultured in corneal ulcers of soft contact
lens users has been noted in surveillance data, researchers
reported at the 2006 joint meeting of the American Academy of
Ophthalmology and Asia Pacific Academy of Ophthalmology in
Las Vegas, Nevada.
According to lead investigator Eduardo C. Alfonso, MD,
professor of ophthalmology at the University of Miami in Florida,
the data reflect infections that are referred for clinical studies to
the ocular microbiology laboratory at the Bascom-Palmer Eye
Institute.
"Compared to the previous studies that we reported in 1978,
1980, 1986, and 2000, the current study shows a marked
increase in the number of nonbacterial pathogens that we have
been culturing in soft contact lens users," Dr. Alfonso said.
The retrospective review, which included data from 1459
cultures collected during 2004 and 2005, showed a 140%
increase in the recovery of Acanthamoeba (from 5 to 12
cases/year), and a 500% increase in recovery of fungal
pathogens (from 2 to 12 cases/year).
An outbreak of fusarium keratitis cases among contact lens
users was reported by Dr. Alfoso as well as by other
researchers earlier this year. On April 10, 2006, Bausch and
Lomb reported in a news release that a majority of the cases
investigated to date had occurred in contact lens wearers using
ReNu with MoistureLoc lens care solutions. The company
voluntarily initiated a global recall of that product on May 15,
2006.
"The only caveat is that we don't know what the total
denominator is for patients who wear contact lenses," Dr.
Alfonso told Medscape. "If we assume there has been no
difference in that number and we have this increase in the
number of patients with amoeba and fungal infections, then this
is a significant public health issue."
In current clinical practice, corneal ulcers associated with
contact lens use are commonly treated with broad-spectrum
antibiotics, often without first performing a culture. "Between
97% and 99% of corneal ulcers have been associated with
bacterial infections in this population," said Oliver D. Schein,
MD, MPH, professor of ophthalmology at the Wilmer Eye
Institute at Johns Hopkins University in Baltimore, Maryland.
"According to conventional wisdom, any lesion that does not
improve within 2 days of treatment warrants additional
attention."
However, this clinical behavior may no longer be acceptable if a
higher incidence of amoebae and fungi in corneal ulcers is
confirmed by broader studies, which Dr. Alfonso hopes to
encourage other organizations to perform.
"We're presenting at the Academy to raise a red flag," Dr.
Alfonso said. "Our current practice will not treat these types of
infections. If the pathogens are allowed to grow, there may be
detrimental effects to the patient's vision by the time the
clinician realizes that the infection is not responding
appropriately."
Dr. Alfonso's past research on fusarium keratitis was funded by
a grant from Research to Prevent Blindness.
2006 Joint Meeting of the AAO and APAO: Abstract PA062.
Presented November 13, 2006.
and amoeba infections cultured in corneal ulcers of soft contact
lens users has been noted in surveillance data, researchers
reported at the 2006 joint meeting of the American Academy of
Ophthalmology and Asia Pacific Academy of Ophthalmology in
Las Vegas, Nevada.
According to lead investigator Eduardo C. Alfonso, MD,
professor of ophthalmology at the University of Miami in Florida,
the data reflect infections that are referred for clinical studies to
the ocular microbiology laboratory at the Bascom-Palmer Eye
Institute.
"Compared to the previous studies that we reported in 1978,
1980, 1986, and 2000, the current study shows a marked
increase in the number of nonbacterial pathogens that we have
been culturing in soft contact lens users," Dr. Alfonso said.
The retrospective review, which included data from 1459
cultures collected during 2004 and 2005, showed a 140%
increase in the recovery of Acanthamoeba (from 5 to 12
cases/year), and a 500% increase in recovery of fungal
pathogens (from 2 to 12 cases/year).
An outbreak of fusarium keratitis cases among contact lens
users was reported by Dr. Alfoso as well as by other
researchers earlier this year. On April 10, 2006, Bausch and
Lomb reported in a news release that a majority of the cases
investigated to date had occurred in contact lens wearers using
ReNu with MoistureLoc lens care solutions. The company
voluntarily initiated a global recall of that product on May 15,
2006.
"The only caveat is that we don't know what the total
denominator is for patients who wear contact lenses," Dr.
Alfonso told Medscape. "If we assume there has been no
difference in that number and we have this increase in the
number of patients with amoeba and fungal infections, then this
is a significant public health issue."
In current clinical practice, corneal ulcers associated with
contact lens use are commonly treated with broad-spectrum
antibiotics, often without first performing a culture. "Between
97% and 99% of corneal ulcers have been associated with
bacterial infections in this population," said Oliver D. Schein,
MD, MPH, professor of ophthalmology at the Wilmer Eye
Institute at Johns Hopkins University in Baltimore, Maryland.
"According to conventional wisdom, any lesion that does not
improve within 2 days of treatment warrants additional
attention."
However, this clinical behavior may no longer be acceptable if a
higher incidence of amoebae and fungi in corneal ulcers is
confirmed by broader studies, which Dr. Alfonso hopes to
encourage other organizations to perform.
"We're presenting at the Academy to raise a red flag," Dr.
Alfonso said. "Our current practice will not treat these types of
infections. If the pathogens are allowed to grow, there may be
detrimental effects to the patient's vision by the time the
clinician realizes that the infection is not responding
appropriately."
Dr. Alfonso's past research on fusarium keratitis was funded by
a grant from Research to Prevent Blindness.
2006 Joint Meeting of the AAO and APAO: Abstract PA062.
Presented November 13, 2006.
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