Causes for dry eyes and remedies for the condition

Not only sitting before computers for a long time, even smoke and pollution can cause  watery, burning, irritated or red eyes, and most importantly dry eyes.

Dry eye is a common condition that happens when your eyes don’t produce enough tears or the tears evaporate too quickly. It can be uncomfortable, and cause some pain, redness, and a burning sensation in your eyes.

Some people might get up in the morning unable to open the eyes properly because of dry eyes. 

Some of the most common reasons for waking up with dry eyes are:

• your eyelids aren’t remaining tightly closed during sleep (Nocturnal lagophthalmos)
• you aren’t producing high-quality tears to lubricate your eyes
• you aren’t producing enough tears to lubricate your eyes

Nocturnal lagophthalmos is the inability to fully close the eyelids when sleeping. It’s thought to be caused primarily by the weakness of the 7th cranial nerve, also known as the facial nerve.

There are various causes for facial nerve weakness, including:

• skull or jaw trauma
• injury to the cerebellar artery, which delivers the facial nerve’s blood supply
• Bell's Palsy, a sudden but temporary facial muscle weakness

To protect and nourish the front surface of the eye, tears have three layers. These include the water, mucus, and oil layers.

The water layer hydrates the eye, while the oil layer prevents the water layer from evaporating. The mucus layer spreads the tears evenly over the surface of the eyes.

All three of these layers are needed to produce tears. If any of these layers aren’t produced at a great enough volume, tear quality drops.

Keratoconjunctivitis sicca is the most common form of dry eyes. It’s caused by an inadequate amount of water in the tears.

Tears are produced by glands around and in the eyelids. There are a number of reasons you might not be producing enough tears. These include:

. Age. Dry eyes are common with older age. Most people over age 65 encounter some dry eye symptoms.
.Medical conditions. Blepharitis (eyelid inflammation) can result in low tear production. Low tear production can also be the result of thyroid problems, diabetes, rheumatoid arthritis, or Sjögren’s syndrome.
.Medication side effects. Decongestants, antihistamines, antidepressants, and blood pressure medications can all negatively impact tear production.

Depending on your specific situation, any of the following treatment helps  :

• Artificial tear drops. You can purchase over-the-counter eye drops that can add lubrication to your eyes. Your doctor might suggest a heavier ointment for use during sleep.
• Punctal occlusion. This is a procedure in which your doctor will close the duct that drains tears from your eyes (punctum).
• Thermal pulsation. If the glands that produce the oil in your tears (meibomian glands) are blocked and causing dry eyes, your doctor might suggest a thermal pulsation system (LipiFlow). This system heats and massages the blockage to remove it.

Things you can do to minimize irritation and the risk of any longer term effects.

Environmental effects ...

The eye's surface is continuously exposed to the environment, except when our eyes are shut when we sleep.

Bushfire smoke contains dust, fumes (such as carbon monoxide and nitrogen oxides), and tiny particles called PM10 and PM2.5.

When the smoke comes into contact with our eyes, the fumes and small particles dissolve into our tears and coat the eye's surface. In some people, this can trigger inflammation, and therefore irritation.

The presence of a marker called matrix metalloproteinase-9, or MMP-9, indicates the eye is inflamed.

During periods of poor air quality from bushfires in the United States, MMP-9 was present in the eyes of more people than it ordinarily would be.

Longer term risks ...

We know very little about how pollution from bushfire smoke might affect our eyes over the longer term, or what damage repeated or chronic exposure might do.

But we do know people who live in areas with high levels of air pollution, such as China, are three to four times more likely to develop dry eye.

Dry eye is a condition where a person doesn't have enough tears or they are of such poor quality they don't lubricate and nourish the eye. We need high quality tears to maintain the health of the front surface of the eye and provide clear vision.

For people who already have dry eyes—often older people—poor air quality may increase the damage. The smoke and pollution may cause intense stinging and a feeling of grittiness to the point they can barely open their eyes.

While dry eye is a result of damage to the surface of the eyes, it's also possible pollutants entering the blood stream after we breathe them in could affect the blood supply to the eye. This in turn could damage the fine vessels within the eye itself.

Research has suggested high levels of air pollution in Taiwan may increase the risk of age-related macular degeneration, which could be an example of this.

Pollution and  smoke could be causing subtle damage to the eyes, even in people without any symptoms. So

• the best option is to avoid going outside when air quality is at is worst, where possible
• wearing sunglasses or glasses when outside if you need them might stop some of the dust carried in the wind from contacting the eye's surface (but it won't stop the tiny particles getting in)
• avoid wearing contact lenses if possible.

 If your eyes are irritated ...

• flush your eyes as often as you can, with over-the-counter lubricant eye drops if you have some on hand. If not, use sterile saline solution or clean bottled water
• if your eyes are itchy, flush them and then place a cool face washer over your closed lids
• don't rub your eyes, as this could make the irritation worse.

If your eyes are red and sore and these steps don't help, it's best to see an eye care professional.