Most people who are diagnosed with pink eye often receive a prescription for antibiotic eye drops, but this might not be the proper treatment according to new research.

In fact, the eyedrops may even make the infection worse for some people who receive the medication. So, why aren’t the drugs effective? Nearly all pinkeye cases are the result of a virus, rather than bacteria, which antibiotics fight against, according to a study from the University of Michigan Kellogg Eye Center.

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“This study opens the lid on overprescribing of antibiotics for a common eye infection,” lead author Dr. Nakul Shekhawat said in a statement on ScienceDaily. “It shows that current treatment decisions for pink eye are not based on evidence, but are often driven more by the type of health care practitioner making the diagnosis and the patient’s socioeconomic status than by medical reasons.”

The study, published in the journal Ophthalmology, included data from more than 340,000 patients diagnosed with acute conjunctivitis, commonly known as pink eye. Out of all the patients, 58 percent were given prescriptions for antibiotic eye drops. Dr. Shekhawat and his colleagues found that the chances of a person filling their prescriptions depended more on their socioeconomic status rather than if they were at a high risk of developing a more serious infection. Those who filled their prescriptions tended to be white, younger, better educated, and more affluent than participants who didn’t fill theirs.

It was also revealed that most people in the study - about 83 percent - did not go to an eye care specialist for treatment, but rather a primary care provider, such as a family physician or urgent care provider. Compared to those seen by an ophthalmologist or optometrist, patients who saw family practice doctors, as well as other non-eye specialists, were two to three times more likely to fill their antibiotic eye drop prescriptions.

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“The proportion of patients who filled prescriptions for antibiotics was indeed much higher than we had expected,” co-author Dr. Joshua Stein, told TIME.

While most people don’t need antibiotic eyedrops to treat their pink eye, there’s rare cases when the infection is caused by bacteria and therefore, antibiotics will help. However, in most cases the infection doesn’t involve any treatment. Instead, general symptom relief is recommended. Doctors may suggest using artificial tears, cleaning eyelids with a wet cloth, and applying cold or warm compresses multiple times a day, according to Mayo Clinic. Additionally for those who wear contacts, it’s recommended to stop wearing them until your eyes are no longer irritated.

See also: What Happens If You Stop Antibiotics Early? Avoiding Antibiotic Resistance While Protecting Against Infection

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