Blurry Vision and Chronic Dry Eye
Reviewed by: HU Medical Review Board | Last updated: May 2023
Vision problems with dry eye can be frustrating. You know it is happening, but then the problem is gone quite literally with a blink of an eye. Even if you remember to tell your doctor that you have periodic blurry vision, your doctor may not find any clues to that on an exam.
This is a common problem in dry eye disease. Blurred or hazy vision that comes on suddenly and seems to disappear just as quickly is a problem experienced by many with dry eyes.1
Understanding the possible causes of your vision problems can help you talk to your doctor about what you are experiencing and take steps to improve your symptoms.
The role of the cornea in vision
The cornea is the thin, clear membrane covering the surface of your eye. The cornea serves 2 major purposes: protection and refraction (bending) of light for normal vision.2
The cornea relies on tears to maintain moisture. When the tears are working right, you blink and may not even notice your eye. When there is a problem with the moisture on the cornea, you can tell. It may feel like there is something in or on your eye.
What is the tear film?
The reason the cornea is good at allowing you to see is because of the tear film. The tear film is the perfect mix of oil on water, held onto the surface of the eye by mucus. The tears are continuously smoothed over the eye with every blink. Without the moisturizing tears on its surface, the cornea is not a polished lens. Instead, the cornea is rough like sandpaper. In addition to the cornea, the tear film is also involved in focusing light for normal vision.3
For someone with normal eye moisture, the corneal surface stays moist between blinks. This allows for easy, smooth blinking. In dry eye disease, the eye surface becomes dry between blinks. The rough corneal surface leads to light scattering and blurry vision that occurs with dry eyes. Blinking often happens less in dry eye disease, making the condition worse.3
Why does my vision fluctuate?
Researchers have studied how vision changes between blinks. In a study of 18 people with dry eye disease and 17 people without dry eyes, results showed that those with dry eye disease lose vision more than twice as fast as those without dry eye. Some of the people with severe dry eye symptoms lost vision within 2 seconds of blinking.3
Vision that comes and goes due to dry eye might seem like looking through a windshield during a rainstorm. The windshield seems clear 1 moment right after the wipers are finished sweeping, but then it quickly becomes blurry and difficult to see through as rain continues to fall on the windshield. Your blink is like the wipers on your windshield, clearing your vision once again. Because those with dry eyes have been shown to blink less, your vision can suffer, particularly in between blinks.1
How to talk to your doctor
You are not alone in your vision problems with dry eye. A big part of getting the answers and care you need is telling your doctor how you are feeling. Dry eye disease is long-term and seems to get worse over time. Talking to your doctor about how you feel will hopefully get you closer to the treatment you need.