If you’ve been thinking about buying some of those blue light glasses to help you avoid straining your eyes, you may want to hold off for now.

Research that’s gone into blue light glasses has not proven they’re effectiveness, according to Dr. Nicole Bajic with the Cleveland Clinic.

While some people might think they notice a difference while wearing them, it could just be a placebo effect, she cautioned.

So what can you do to help with eyestrain instead? Cleveland Clinic officials recommend using the 20-20-20 rule. That’s where you take a break every 20 minutes, and then look at something 20 feet away for 20 seconds.

“For people who are, you know, doing extended work and they notice that things are not feeling so great, their eyes are feeling a little achy or they get headaches, you know, it could be a simple matter of just correcting their natural prescription,” Bajic said.

If you’re 40 years or older, you should be getting an annual eye exam, Bajic said. Anyone younger than 40 should speak with their physician.