People looking to a popular online symptom checker for answers about eye problems often get a wrong diagnosis, a small study suggests.

While some studies have already documented many ways that symptom checkers can mislead patients, less is known about how well they work specifically for eye conditions, the researchers note in JAMA Ophthalmology.

For the current study, they tested how often an online symptom checker offered by WebMD generated the correct diagnosis for 42 clinical vignettes similar to situations that patients might describe to doctors in person.

They wanted to see how often the symptom checker provided the correct diagnosis or at least generated the right diagnosis as one of the top three possible answers.