Do your eyes well up as you walk out the door into the cold?
Watery eyes are common in winter, but you might be surprised at what causes you to tear up.
“Tears are a lot more complicated than most people realise,” Andrew Hogan, president of Optometry Australia, told ABC Radio Hobart.
Tears are divided into three types:
- Basal tears — the constant liquid that keeps your eyeballs from drying out.
- Reflex or reactionary tears — extra tears when you get something in your eye or they’re stimulated from an irritant, like chopping onions.
- Crying or weeping, also known as psychic tears — the tears of emotion. The purpose for these tears is unclear.
When your eyes get watery in the cold outside, those are reactionary tears.
“What’s happening when you walk outside and your eyes water is technically dry eye,” Mr Hogan said.
“Essentially your tears that you have coating the front of your eye, the tear film, evaporates really quickly because of, usually, wind.”
What tears are made of
- The liquid in your eyes is made up of three layers.
- The layer next to the eyeball is a mucus layer to help tears stick to the eyeball.
- The middle layer is saltwater, used to clean the eye.
- The top layer is an oil that keeps your vision clear by smoothing the liquid.
- Each layer is produced by a different gland, so it’s best to get dry eyes tested to find out which layer is the problem.
Dry eyes from a cold wind are not much of a problem, as long as the feeling does not last too long.
“Those tears are not very sticky, they’re very watery and they don’t really stay in the eye,” Mr Hogan said.
“They’re the sort of tears that are useful for washing a bit of sand out of our eyes, but they actually don’t moisturise our eyes very well.
“It becomes a cycle where the watery eye doesn’t moisturise the eye and the brain makes more wateriness to compensate and it never quite gets better.
“That’s why after you’ve had a good cry, your eyes are often red and feel a bit gritty, because they haven’t been moisturised.”
A common cause of ongoing dry eye is Meibomian gland dysfunction — the gland that makes the oil layer of tears.
Crying a lot actually leaves your eyeballs too dry by washing away the mucus and oil layers
“If your Meibomian glands don’t work properly, no matter how many tears you may make, your eye never quite feels properly moistened,” Mr Hogan said
Meibomian glands are like sweat glands and a blocked or infected one is what is known as a sty.
Mr Hogan said while you could not tell a person’s general health through their tears, dry eye was a common side effect of many health conditions and medications.
Eye drops are the most common way to treat dry eye, but there are different eye drops to fix different problems, so it is worth getting your eyes checked before buying off the shelf.
“There’s a lot of things it could be,” Mr Hogan said.
“It’s worth ducking in and getting someone to have a look at it, as it’s more than likely it’s something pretty easy to fix.”