This article is for informational purposes only and does not diagnose any conditions
Anyone can experience the symptoms of dry eye, and nearly half of all Americans have at one time or another. Dry eye symptoms occur most commonly in people over 50 years of age, and more often in women than men. According to the data collected by the American Academy of Ophthalmology, approximately 5 million people in the United States over age 50 have dry eye.
What are the symptoms of Dry Eye?
Symptoms of dry eye usually affect both eyes and may include:
Sensitivity to light (photophobia)
Stinging or burning sensation
Sticky or dry sensation
Pain or aching sensation
Eye fatigue or heavy feeling eyes
Foreign body sensation (gritty feeling or something in your eye)
Difficulty wearing contact lenses
Excessive tearing or mucus
The symptoms of dry eye can fluctuate and be more intense and uncomfortable in certain situations, environments, or times of day. Some people find that their symptoms may be worse on an airplane, in an air-conditioned room, a vehicle, or if they have been doing computer work or reading for long periods.
The symptoms of dry eye can be debilitating and cause decreased visual function and negatively impact workplace productivity and quality of life.
How can excessive tears be a symptom of dry eye?
It may seem odd, but excessive tear production or watery eyes can be a symptom of dry eye. Several of the other symptoms associated with dry eye such as the stinging or scratchy sensations, can signal the lacrimal glands (tear glands) to produce more tears as a natural response or reflex to the irritating stimuli. These tears are often very watery and do not contain adequate amounts of lipids (oils) or mucus which are the key components that keep tears on the eye surface longer and provide needed relief of symptoms.
Should I see a doctor for dry eye symptoms?
Treatments are available for dry eye that can help to temporarily alleviate the symptoms or address any underlying cause of more chronic (long term) dry eye.
If symptoms persist and eyes continue to feel irritated, tired, or painful, you should consult a physician or eye care professional that can examine your eyes and determine the cause of your dry eyes. They can discuss treatment options or lifestyle modifications that may provide relief, or they can make a referral for specialty care.
Although many symptoms of dry eye are subtle and can only be mildly irritating, there can be serious consequences to your eye health if symptoms become more severe or are constant over a long period of time. Chronic inflammation and infection can occur, as well as damage, ulceration, or scarring of the cornea (front surface of the eye) that can result in permanent vision loss.
It is well known that dry eye is a common occurrence after laser refractive surgery (LASIK) or cataract surgery and surgeons usually discuss different treatment options with patients after surgery.  Ongoing dry eye symptoms before eye surgery can also affect the vision outcomes of LASIK or cataract surgery. Dry eyes can cause large distortions (optical aberrations) when compared to normal eyes, which can lead to inaccurate calculations of the lens that is put in to replace lens removed during cataract surgery. 
What diseases or health conditions cause dry eye symptoms?
High Blood Pressure (hypertension) doesn’t usually cause dry eye by itself, but many high blood pressure medications can result in dry eye. Diuretics (e.g., “water pills”) are a common class of medication that are used to treat high blood pressure. Diuretics work by having the kidneys increase the amount of salt and water that pass through the body in the form of urine. The reduction in bodily fluid reduces the overall fluid going through the blood vessels, thereby lowering blood pressure. This reduction in overall fluid in the body can result in reduced tear production and symptoms of dry eye.
Diabetes can cause changes to occur in someone’s blood vessels and nerve tissue. Tear production is controlled by sensations from the corneal nerves, triggering the lacrimal glands to make more tears. Diabetes-related nerve damage and fluctuations in blood sugar can lead to reduced tear production and dry eye symptoms.
Aging naturally causes changes to hormone production and regulation. Hormones, including androgens, glucagon, and corticotrophin all influence the amount and quality of tears produced. People may experience reduced volume of tears or that the tears do not adhere to the eye surface (watery tears) because they do not contain enough mucus or lipids. Hormone replacement therapy or hormonal birth control pills can influence tear quantity, quality, and can also affect blink rate.
People with lupus often experience dry eye symptoms. Lupus is an autoimmune disease, which means that the immune system attacks healthy tissue by mistake instead of fighting germs and viruses. Inflammation that leads to pain and swelling can occur anywhere in the body, and when it impacts the eyes it can negatively impact lacrimal and meibomian glands, reducing the amount and quality of tears.
Sjogren’s syndrome is a chronic inflammatory disease that affects mostly females and causes dry eyes, dry mouth, joint pain, swelling, stiffness, swollen salivary glands, dry throat, coughing, and fatigue. Dry eye symptoms often develop before someone is diagnosed with Sjogren’s syndrome.
Arthritis commonly leads to inflammation in various parts of the body, including the eyes. Inflammatory conditions such as iritis (inflammation of the iris – colored part of the eye) and scleritis (inflammation of the white part of the eye), often develop with arthritis. Inflammatory cells and debris can build up in the lacrimal gland and alter the surface of the eye, causing dry eye symptoms which can be severe, leading to scarring and vision loss.
What are the clinical signs and symptoms that eyecare providers use to diagnose dry eye?
Eyecare providers have several tools and assessments available to help them to diagnose dry eye and determine the underlying cause. By determining the cause, it is more likely that an effective treatment can be initiated. Due to the fluctuation of symptoms that some people experience, diagnosis can be difficult, particularly in the early stages, because symptoms may be present without measurable clinical signs. Alternatively, patients in the later stages of dry eye disease may become desensitized to their symptoms caused by damage to the eye surface that has already occurred and claim to experience minimal symptoms, but their clinical examination is abnormal. This is more common in patients with chronic dry eye caused by a systemic disease or hormonal changes.
Ophthalmologists and optometrists will perform a thorough (comprehensive) eye examination. They will review the patient’s overall health (disorders, medications, etc.) and perform external examination of the eye to see if there are any structural abnormalities and if there is any infection or inflammation present.
Other diagnostic assessments may include:
Blink Frequency – Evaluation of the number of times someone blinks per minute. Blinking distributes tears over the eye surface and washes away potential irritants. A normal resting blink rate is estimated at 8-21 blinks per minute, but focussing on specific visual tasks, such as reading or working on the computer, can reduce blink rates 60% and cause symptoms of dry eye.  Medications, such as hormonal birth control, can also affect blink rate. Disorders related to dopamine levels can also decrease (Parkinson’s disease) or increase (schizophrenia) blink rates. 
Schirmer's test - Measures the quantity of tears produced to determine whether the eye produces enough tears to keep it moist. The test uses a small trip of blotting paper, placed under the lower eyelids. The strip is kept in place for 5 minutes and then the length of the moistened strip is measured. A result of 5mm or less shows a tear deficiency.
TBUT (tear break up time) – Assesses tear quality. TBUT shows how quickly tears evaporate from the eye surface. A drop of fluorescein dye is instilled on the eye surface and the patient is asked not to blink. While the dye is on the eye surface, a broad slit-lamp beam with a cobalt blue filter scans the tear film. The physician observes for changes or drying of the tear film. Dry spots appear as black spots or lines. The TBUT is measured as the number of seconds that elapse between the patient’s last blink and the appearance of the first dry spot on the tear film. Most normal eyes have a TBUT of 10 seconds or longer.
Corneal Staining - Using dyes on the cornea (the clear surface of the eye) – Fluorescein dye is used to assess the integrity of the cornea (outermost clear surface at the front of the eye) and conjunctival epithelium (the clear, thin membrane that covers the white part of the eye and inside surface of the eye lids). Normal cornea and epithelium do not stain, but if the mucus layer of the tear film is absent, the dye can penetrate and stain the epithelium. A drop of dye will be instilled onto the eye surface and observed for approximately 2 minutes.
Ocular protection index (OPI) – A score that combines tear film instability and blink rate. The OPI is calculated by dividing the TBUT by the blink interval (blink rate/minute divided by 60).
Dry eye can negatively affect quality of life
The symptoms of dry eye, including eye irritation, stinging, dryness, eye fatigue, and visual disturbances can significantly affect and negatively impact someone’s quality of life because of the discomfort and effects on vision. The National Eye Institute Visual Functioning Questionnaire-25 [NEI-VFQ-25]) is a questionnaire that assesses how eye-related disorders impact quality of life. Studies using the NEI-VFQ have shown that people with dry eye scored lower in all categories (subscales), including pain, driving, and general health, than people without symptoms. 
Studies have also shown a link between dry eye symptoms and severe psychological stress, depressive mood, and anxiety/depression problems. 
Costs associated with dry eye symptoms
Dry eye has a significant impact on a person’s life. Dry eye disease carries an economic burden to people and society, including direct costs associated with dry eye disease, such as the cost of eyecare provider visits and over the counter or prescription treatments, as well as indirect costs, such as loss of work days, or reduced work productivity. 
Direct costs associated with dry eye increase as the severity of symptoms increase. A study demonstrated that in the United states the annual average direct medical cost per person with mild, moderate, and severe dry eye symptoms was estimated at US $678, US $771, and US $1,267, respectively. 
Although the indirect costs of dry eye disease are difficult to estimate, there is no doubt that dry eye disease can have a significant impact on a person’s life as well as an overall impact on society.
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