Dry Eye


Symptoms associated with dye eye are among the most common of all problems reported to eye doctors. Tears bathe the eye, washing out dust and debris and keeping the eye moist. They also contain enzymes that neutralize the microorganisms that colonize the eye.

View Video

How it works

Scientifically called the “pre-corneal tear film multi-layer structure”, the tears have a number of specific functions:

  • Provide water to maintain the hydration of the cornea and carry oxygen and nutritional support
  • Carry anti-bacterial and anti-viral cells to protect the exposed structures of the eyeball from infection
  • Carry off debris so it does not damage the sensitive tissue of the eye
  • Provide lubrication between the inside of the lids and the cornea

Chart showing a healthy eye vs one with dry eye

The tear film is composed of three separate layers, distributed according to weight, heaviest to lightest:

  • Mucus – lies against the eyeball
  • Water – the middle layer
  • Oil – covers the other two

The lacrimal gland, located in the eyelids above the eyeball, is the main producer of these components. In a properly functioning system, the three layers are produced in perfect balance, mixed and distributed across the eyeball with every blink. You are normally unaware of the tear film’s existence.

View Video

Occasionally though, something happens to disrupt the natural balance of components and our bodies try to compensate in the simplest manner: produce more tears. The problem is that these tears produced, quickly upon demand, are reflex tears (see below) and they simply run off the now destabilized tear film. The resulting dry spots on the cornea cause the eyes to get red and irritated, resulting in more discomfort, which causes more reflex tearing, further destabilizing the tear film: resulting in an endless loop of discomfort called dry eye.

Types of tears

The name “dry eye” can be a little confusing since one of the most common symptoms is excessive watering. In the picture to the right, notice the purplish Rose-Bengal staining. The white of the eye normally should not take up any stain. Even though there is no deficiency of tear production, the eye is dry because the tear film is very unstable and breaks easily. There may be increased evaporation of tears as well. The symptoms are of constant eye irritation. To understand better how this works, learn about the two different types of tears:

Lubricating tears are produced slowly and steadily throughout the day. Lubricating tears contain a precise balance of mucous, water, oil, nutrient proteins, and antibodies that nourish and protect the front surface of the eye.

Reflex tears, also called lacrimal tears, consist mostly of just water and salt and do not have much lubricating value. Reflex tears serve as a kind of emergency response to flood the eye when it is suddenly irritated or injured. Reflex tears might occur when you get something in your eye, when you’re cutting onions, when you’re around smoke, or when you accidentally scratch your eye. The reflex tears gush out in such large quantities that the tear drainage system can’t handle them all and they spill out onto your cheek. Still another cause of reflex tearing is irritation of the eye from lack of lubricating tears. Even if you have tons of reflex tears, if your eye is not producing enough lubricating tears, you have dry eye .


These symptoms alone may be enough for your doctor to diagnose dry eye syndrome:

  • Watery eyes
  • Feeling that there’s sand in your eyes
  • Eyes that itch and burn
  • Blurred vision following periods of reading TV, watching or using a computer
  • Red, irritated eyes that produce a mucus discharge


Common causes of dry eye include:

  • Age: glands in the eyelid produce oil that keeps tears from evaporating off the eye. We produce less of this oil as we age.
  • Gender: dry eye syndrome is more common in women, possibly due to hormone fluctuations, especially after menopause, or due to birth control pills
  • Diseases: including diabetes, Parkinson’s, lupus, rheumatoid arthritis, thyroid dysfunction, rosacea or Sjogren’s syndrome (a triad of dry eyes, dry mouth, and rheumatoid arthritis or lupus)
  • Related conditions: incomplete closure of the eyelids, eyelid disease and a deficiency of the tear-producing glands
  • Dehydrating irritants: such as smoking, alcohol, caffeine
  • Prescription medications: including some high blood pressure medications, antihistamines, diuretics, antidepressants, anti-anxiety pills, sleeping pills and pain medications. Over-the-counter medications including some cold and allergy products, motion sickness remedies, and sleeps aids
  • Environmental: hot, dry or windy conditions, high altitude, air-conditioning, chemical vapors, heating, and smoke
  • Intensive and prolonged near vision tasks: reading, using a computer, watching TV – due to the fact that the blink rate decreases
  • Contact lenses: a very common side effect. Recent research indicates that contact lens wear and dry eyes can be a vicious cycle. Dry eye syndrome makes contact lenses feel uncomfortable, and the rubbing of the lenses against the conjunctiva seems to be a cause of dry eyes, according to a report in the January 2001 Contact Lens Academy of Optometry Journal .
  • Eye surgery: some types of eye surgery can aggravate dry eye.
  • Inflammation: recent research suggests that dry eye may also be caused by inflammation due to an imbalance of “good” fats and “bad” fats and that eating a lot of omega-3 fatty acids (found in cold-water fish) may decrease your risk.


You should have an examination to determine whether you actually have dry eyes and if so which type. Around 80% of patients have dry eyes due to lack of tear volume (aqueous or water layer deficiency) and 20% have dry eyes by evaporation where plug treatment is inappropriate. For evaporative dry eyes a different treatment is prescribed. Many patients have both aqueous and evaporative components to their dry eye, so tests are needed. There are several methods used to test for dry eye:

View Video

  • Examining the eyes with magnifying instruments
  • Measuring the rate of tear production using thin strip of filter paper placed at the edge of the eye, called a Schirmer test
  • Checking the amount of time it takes for tears to evaporate between blinks. Tear evaporation rate is counted as the number of seconds after a blink before the tear film destabilizes and tear volume assessed by analyzing the “pool” of tears clinging along the edge of the lower eyelids. The dynamic flow of tears over the surface of your eye following a blink and the size of your tear ducts are also noted.
  • Checking for pinpoint scratches on the front surface of the eye caused by dryness using special, colored eye drops call fluorescein or Rose Bengal. A fluorescent yellow dye is painlessly introduced into the tears of each eye. Viewed with a microscope under blue light, any area on the surface of the eye damaged by dehydration glows brightly.


  • Artificial tears
  • Environmental
  • Punctal occlusion
  • Nutrition
  • Removing cause
  • In The Future

View Video

Artificial tears

The treatment of a dry eye involves re-establishing the normal relationship between the three tear layer components. The most common treatment is use of artificial teardrops , of which there are a number of brands and formulations – liquids, gels and ointments (most often recommended for nighttime use). The primary differences are: preservatives or non- preserved, and the level of viscosity (thickness), and lubricating (slipperiness) agents.

Many different brands of artificial tears are available over-the-counter. Lanolin-free ointments are preferable for those with allergy to wool. Unpreserved tears may be recommended for people whose eyes are sensitive to preservatives. The down side of preservative free products is their limited shelf life and the possibility of contamination from misuse (the tip of the dropper must not contact the eye or fingers). Single use containers solve most of these problems. Users must not allow the packaging to be exposed to extremes in temperature.

How to:

If your doctor recommends frequent use, this means every one or two hours. Proper application requires the placement of one drop into the sack created when you gently pull the lower lid out and away from the eyeball.

You then close your eyes slowly, open and blink once (to mix the drop with the natural tears) and then close the eyes for 30 seconds. This allows the artificial tears to form temporary attachments to the ocular surface, prolonging the beneficial effects.

This therapy is continued for three to five days (up to two weeks if severe symptoms), then the frequency is diminished – first using the drops every fours hours, then every six hours over the next week or so. You will find that there is a certain frequency of administering the drops that maintains comfort. Sometimes it is possible to slowly taper off the artificial tears completely. It appears that, if the underlying cause is mitigated, the use of tear replacements may stabilize the tear layer situation, allowing the body to resume normal tear film production.

It is not appropriate to prescribe tear replacement drops for use as needed or desired. By the time the person experiences dry eye symptoms, the tear film has already destabilized, the cornea surface has been impacted and the syndrome has been established. Proper treatment is designed to prevent this situation from occurring by intervening early on in the process and encouraging the body to create a more normal environment.

Restasis eye drops (cyclosporine in a castor-oil base) go one step further: they help your eyes to increase tear production. Restasis treatment is the first of its kind, and can be very useful in certain cases of dry eye syndrome. Restasis is a newer artificial teardrop that has been very effective in a number of patients.


When infection, inflammation of the eyelids or clogged oil glands contribute to dry eye, special lid cleaning techniques or antibiotics may be recommended. It may also help to avoid hot, dry or windy environments or to humidify the air in your home or office.

Punctal occlusion

Punctal occlusion is a medical treatment for dry eye that may enable your eyes to make better use of the few lubricating tears you do produce. Plugging the lacrimal (tear) ducts keep tears in your eye from draining away as quickly.

How this works:

There are four opening in the eyelid called puncta that drain tears from the eye into the nasal-lacrimal duct and ultimately into the throat. Plugs can be painlessly inserted into the puncta, and are normally not felt once inserted. These plugs can be temporary, made from a dissolvable collagen – excellent as a diagnostic aid. They can be semi-permanent, made of silicone. Or, the puncta can be permanently closed by cautery, a procedure useful as a more permanent treatment for a condition that cannot otherwise be mitigated (read more).


Sometimes special nutritional supplements are beneficial for dry eyes. Studies have found that supplements containing certain essential fatty acids – linoleic, gamma-linoleic, and omega-3 found in cold-water fish – can decrease dry eye symptoms.

Removing cause

If medications are the cause of dry eyes, sometimes switching to a different type of medication alleviates the dry eye symptoms while keeping the needed treatment. In some cases, the benefits of the drug must be weighed against the side effect of dry eyes.

Treating any underlying eyelid disease helps as well. This may call for antibiotic or steroid drops plus frequent eyelid scrubs with an antibacterial shampoo.

In The Future

Quite a few products are in clinical testing for possible dry eye treatment. For example, both trehalose (a carbohydrate) and castor oil solutions improved dry eye symptoms in small studies, and further testing is underway. As advancements are made, we will continue to update this section.

Cataract Lens Icon


Learn about cataracts and their treatment

Learn more about Cataracts
Crosshairs Icon

Laser Vision

LASIK, PRK, Implants, and other

Learn more about LASIK
Lightbulb Icon


Glaucoma, Macular Degeneration,
Medical Eye Exams, and other

LEarn More about Eye Conditions