When you blink, a film of tears spreads over the eye. This keeps the eye’s surface smooth and clear. The tear film is important for good vision.
Three Layers of Tear Film
The tear film is made of three layers:
- An oily layer
- A watery layer
- A mucus layer
Each layer of the tear film serves a purpose.
The oily layer is the outside of the tear film. It makes the tear surface smooth and keeps tears from drying up too quickly. This layer is made in the eye’s meibomian glands.
The watery layer is the middle of the tear film. It makes up most of what we see as tears. This layer cleans the eye, washing away particles that do not belong in the eye. This layer comes from the lacrimal glands in the eyelids.
The mucus layer is the inner layer of the tear film. This helps spread the watery layer over the eye’s surface, keeping it moist. Without mucus, tears would not stick to the eye. Mucus is made in the conjunctiva. This is the clear tissue covering the white of your eye and inside your eyelids.
Normally, our eyes constantly make tears to stay moist. If our eyes are irritated, or we cry, our eyes make a lot of tears. But sometimes the eyes don’t make enough tears, or something affects one or more layers of the tear film. In those cases, we end up with dry eyes.
Dry Eye Symptoms
Here are some of the symptoms of dry eye:
- You feel like your eyes are stinging and burning.
- Blurred vision, especially when reading.
- There is a scratchy or gritty feeling like something is in your eye.
- There are strings of mucus in or around your eyes.
- Your eyes are red or irritated. This is especially true when you are in the wind or near cigarette smoke.
- It is painful to wear contact lenses.
- You have lots of tears in your eyes.
Having a lot of tears in your eyes with dry eyes might sound odd. But your eyes make more tears when they are irritated by dry eye.
There are many ways to treat dry eye:
- Use protective eyewear to block dry air
- Humidify indoor air
- Avoid ceiling fans
- Position the computer screen below eye level
- Avoid exposure to smoke
- Use artificial tears
- Exercise the eyes at frequent intervals by blinking & closing the eyes
- Eat a diet rich in Vitamin A (liver, carrots, and broccoli)