When you purchase over-the-counter eye drops to treat allergies, dry eye, infections or glaucoma, the directions probably sound pretty simple. Believe it or not, many people make mistakes when using these drops. While they might not seem like a big deal, these errors can lower the effectiveness of the medication or pose risk to your vision.

Below are five common mistakes people make with OTC eye drops and ways to prevent them from happening to you.

1. Using More Eye Drops than You Need To

We often assume that using more of something will lead to faster or better results, but this isn’t the case with eye drops. In fact, it can have the opposite effect. For example, if you have dry or itchy eyes, you might think that using larger drops will provide faster relief. But putting too many drops into your eye causes drainage, reducing the amount of medication in your tear duct. Instead, pay attention to your technique and not the volume.

2. Blinking After Using the Drops

Unless the drop specifically tells you to blink, blinking is actually counterproductive. Many people assume that blinking spreads the drops across the eye, but this isn’t true. In reality, blinking causes some of the drop to leak from the eye, preventing maximum absorption. After applying the eye drops, close your eyes and press lightly on the corner of your eyelid to close the duct.

3. Mixing Eye Drops

Another frequent mistake is mixing eye drops. Some people take several different drops to manage their condition and they don’t space them out enough. Most eye specialists recommend a 30 minute window in between non-prescription and prescription drops. So, if you have prescription drops, use them in the morning and you have the rest of the day to put the others in.

4. Not Taking Out Contacts

Only certain types of drops can be applied with your contacts in. Otherwise, most drops require your contacts to be removed. The best time to use these drops is in the morning before you put your contacts in. You only have to wait a few minutes. It’s also best to use drops that specifically state “safe for contact lenses.” If you’re not sure, talk to your eye doctor about the best drops to use.

5. Not Seeing an Ophthalmologist

With the internet, many people Google their symptoms and become their own doctor. While the internet is a helpful source of information, we’re guessing that you’re not an eye doctor. How often you should see an eye specialist depends on your age and vision. Your doctor can also rule out other causes for your symptoms.

Even over-the-counter eye drops have their risks, so make sure you’re applying them correctly. And if you’re not sure what you should be using, schedule an appointment with your ophthalmologist. Grabbing the cheapest or first available option can actually worsen your eye condition.