If your ability to see things in sharp focus suddenly declines, and then it improves after blinking or using eye drops, you may have dry eye. This can happen in one or both eyes. The eyes need a continual and consistent film of tears for clear vision. Without high-quality tears to bathe, nourish, and protect the eye surface, your ability to see fine details clearly can decline.

Episodes of blurry vision due to excessive tearing are often a sign of dry eye syndrome. When the eyes produce too few tears, or the tears are not of the right quality, the lacrimal glands can over-compensate by flooding the eye with tears. In most cases, by the time this happens, dry eye has been going on for some time.

The skin condition rosacea also causes dry eye. People with rosacea experience flushing of the nose, cheeks and forehead. In about 60 percent of cases, the inflammation spreads to the white of the eye. Treatments for dry eye due to ocular rosacea differ from treatments for other forms of dry eye, which is why it is important to talk to a doctor if you think you have this condition.

One of the common causes of dry eye is blepharitis or meibomian gland dysfunction. This happens when the glands in the eyelid that release the oils and proteins in tears become blocked. The eyelids become inflamed and sometimes a crust may develop around the edges of the eye. Gentle cleansing with warm water can open the glands. It is important to talk to an eye care specialist if this condition persists.

If it feels like there is a sticky substance in your eye, you may have dry eye syndrome. Tears need a specific balance of lipids, water and mucus to keep the eye moist. When the glands that make tears do not produce the right balance of these components, the tears become unstable, resulting in that stringy feeling characteristic of dry eye caused by lacrimal gland dysfunction.

Pain, a burning sensation or difficulty opening the lids in the morning may be signs that you sleep with your eyelids slightly open. This condition, lagophthalmos, affects five to 10 percent of the population and is a common cause of dry eye. Treatments include thick ointments and protective goggles that keep the eyelids closed at night.

About 4 million Americans, mostly women, have Sjögren's syndrome, a systemic disease that affects the production of tears and saliva. Most people with Sjögren's syndrome experience dry eye. However, many people with the condition remain undiagnosed. If you have difficultly producing tears when distressed, speak to a doctor.

About half of all contact lens wearers experience dry eye. This can happen for a number of reasons. If your contact lenses feel scratchy or dry, or if your eyes are red and irritated, it could be time to switch to a different lens cleaning solution or switch to disposable lenses.

Decreased tolerance for reading, working at the computer or any activity that requires continual visual attention is a frequent symptom of dry eye. When people read or stare at a screen for long periods of time, they blink less frequently. This leads to digital eye strain, a condition that affects 65 percent of adults and leads to tired, inflamed and dry eyes.

If bright sunlight or fluorescent lighting irritate your eyes, it could be a sign of eye inflammation or an eye infection, two common causes of dry eye. Photophobia should be taken seriously because it also can be a sign of corneal scratching.