For children with pink eye, antibiotic eyedrops do not resolve symptoms significantly faster than eyedrops that do not have antimicrobial properties ― suggesting that lubrication alone may have a beneficial “washout effect,” researchers in Finland have found.
The vast majority of cases of conjunctivitis resolve with time, and many cases are caused by viruses, according to Chantal Cousineau-Krieger, MD, an ophthalmologist with the National Eye Institute, Bethesda, Maryland. “They’ll get better on their own, even without treatment,” Cousineau-Krieger, who was not part of the study team, said.
The new trial shows that “whether you give someone antibiotics or just lubricating drops, they recover faster than if you do nothing,” she added. “If you give them just lubricating drops, they recover the same as if you gave them antibiotics.”
For the new study, Minna Honkila, MD, PhD, of Oulu University Hospital, and her colleagues conducted a randomized controlled trial that included 88 children aged 6 months to 7 years. Participants were about 3 years old on average, and 52% were girls.
Thirty children in the study received eyedrops containing the antibiotic moxifloxacin. They got better in 3.8 days on average. Twenty-seven children received placebo eyedrops, and they recovered in 4 days on average. The difference between the groups was not statistically significant, according to the researchers.
Another group of 31 children received no intervention. Their symptoms resolved in 5.7 days on average.
The difference between the moxifloxacin group and the no-treatment group (1.9 days) was statistically significant (P = .04), whereas the difference between the placebo group and the no-treatment group (1.7 days) was not (P = .10), the researchers found.
However, a separate analysis found that “both moxifloxacin and placebo eye drops significantly shortened the time to clinical cure relative to no intervention,” Honkila’s group reported in JAMA Network Open.
The rate of relapse of conjunctivitis within 14 days was higher for the children who received moxifloxacin drops (17%) than for those given the placebo drops (7.4%) or no treatment (3.2%), although the differences were not statistically significant, according to the researchers.
Data From Other Trials
The study authors also conducted a meta-analysis in which their findings were combined with results from three other studies. Together, the four studies included 584 children aged 1 month to 18 years.
In the meta-analysis, the use of topical antibiotics was associated with a significant reduction in the proportion of children with conjunctival symptoms on days 3 to 6 after starting treatment, relative to placebo (odds ratio, 0.59).
Pink eye in children is usually caused by bacteria, and “physicians often prescribe antibiotics for this ailment, although the evidence for their effectiveness in pediatric patients is limited and conflicting,” the researchers note. In one of the prior studies, for example, the placebo eyedrops “contained antiseptic agents as preservatives,” so participants in the placebo group may have received anti-infective therapy anyway.
In the new trial, the placebo eyedrops did not contain preservatives, and the investigators included a group that received no intervention, which allowed them to gauge the washout effect from the sham therapy. Participants in the antibiotic and placebo groups received one drop in each affected eye three times per day until conjunctival symptoms were absent for at least 24 hours.
The parents of all the children in the study were advised to remove any discharge from the child’s eyes at least three times a day.
But What About Daycare?
Lubrication tends to be the treatment for conjunctivitis that ophthalmologists prescribe the most. Primary care clinicians may be inclined to prescribe antibiotic eyedrops as a precaution, Cousineau-Krieger said.
Many schools and daycare centers have policies that state that children with pink eye can return after having received antibiotics for 24 hours, she said. That policy could be an additional source of pressure that leads primary care doctors to prescribe antibiotics.
But it is unclear that such policies are based on scientific evidence, and they may result in many people receiving antibiotics unnecessarily, she added.
The study was supported by the Alma and K. A. Snellman Foundation and the Foundation for Paediatric Research, Finland. The researchers have disclosed no relevant financial relationships.
JAMA Netw Open. Published online October 4, 2022. Full text