Dry Eye Defined
What is “Dry Eye”?
Dry eye occurs when the eye does not produce tears properly, or when the tears are not of the correct consistency and evaporate too quickly.
In addition, inflammation of the surface of the eye may occur along with dry eye. If left untreated, this condition can lead to pain, ulcers, or scars on the cornea, and some loss of vision. However, permanent loss of vision from dry eye is uncommon.
Dry eye can make it more difficult to perform some activities, such as using a computer or reading for an extended period of time, and it can decrease tolerance for dry environments, such as the air inside an airplane.
Other names for dry eye include dry eye syndrome, keratoconjunctivitis sicca (KCS), dysfunctional tear syndrome, lacrimal keratoconjunctivitis, evaporative tear deficiency, aqueous tear deficiency, and LASIK-induced neurotrophic epitheliopathy (LNE).
What are the types of dry eye?
1) Aqueous tear-deficient dry eye is a disorder in which the lacrimal glands fail to produce enough of the watery component of tears to maintain a healthy eye surface.
2) Evaporative dry eye may result from inflammation of the meibomian glands, also located in the eyelids. These glands make the lipid or oily part of tears that slows evaporation and keeps the tears stable.
Dry eye can be associated with:
inflammation of the surface of the eye, the lacrimal gland, or the conjunctiva;
any disease process that alters the components of the tears;
an increase in the surface of the eye, as in thyroid disease when the eye protrudes forward;
cosmetic surgery, if the eyelids are opened too widely.
What is the cornea?
The cornea is the clear, dome-shaped outer surface that covers the eye in front of the iris, the colored part of the eye. The cornea helps protect the rest of the eye from germs, dust, and other harmful matter. The cornea bends, or refracts, light entering the eye, and accounts for most of the eye’s total focusing power. It also serves as a filter to screen out most of the damaging ultraviolet (UV) wavelengths in sunlight.
The cornea is a highly organized, clear structure made up of a group of cells and proteins precisely arranged in layers, but it has no blood vessels to nourish or protect it against infection. Instead, it receives its nourishment from the tears and the watery fluid (aqueous humor) that fills the chamber behind it.
Basic anatomy of the eye
What are tears, and how do they relate to dry eye?
Tears, made by the lacrimal gland, are necessary for overall eye health and clear vision. Tears bathe the surface of the eye, keeping it moist, and wash away dust and debris. They also help protect the eye from bacterial and other types of infections.
Tears are composed of three major components: a) outer, oily, lipid layer produced by the meibomian glands; b) middle, watery, lacrimal layer produced by the lacrimal glands; and c) inner, mucous or mucin layer produced by goblet cells located within a thin transparent layer over the white part of the eye and covering the inner surface of the eyelids. Tears are made of proteins (including growth factors), electrolytes, and vitamins that are critical to maintain the health of the eye surface and to prevent infection.
Tears are constantly produced to bathe, nourish, and protect the eye surface. They are also produced in response to emergencies, such as a particle of dust in the eye, an infection or irritation of the eye, or an onset of strong emotions. When the lacrimal glands fail to produce sufficient tears, dry eye can result.
Any disease process that alters the components of tears can make them unhealthy and result in dry eye.
What are the symptoms of dry eye?
Dry eye symptoms may include any of the following:
stinging or burning of the eye;
a sandy or gritty feeling as if something is in the eye;
episodes of excess tears following very dry eye periods;
a stringy discharge from the eye;
pain and redness of the eye;
episodes of blurred vision;
inability to cry when emotionally stressed;
uncomfortable contact lenses;
decreased tolerance of reading, working on the computer, or any activity that requires sustained visual attention;
NOTE: If symptoms of dry eye persist, please schedule a consultation with one of our eye care professionals. This will ensure that you receive an accurate diagnosis of the condition so you may begin treatment to avoid permanent damage. We here at Vision Source Yankee Eye Clinic and Vision Source Rosemount Eye Clinic strive to provide you with the best in personal and professional care.
What are the causes of dry eye?
Dry eye can be a temporary or chronic condition:
Dry eye can be a side effect of some medications, including antihistamines, nasal decongestants, tranquilizers, certain blood pressure medicines, Parkinson’s medications, birth control pills and anti-depressants.
Skin disease on or around the eyelids can result in dry eye.
Diseases of the glands in the eyelids, such as meibomian gland dysfunction, can cause dry eye.
Dry eye can occur in women who are pregnant.
Women who are on hormone replacement therapy may experience dry eye symptoms. Women taking only estrogen are 70 percent more likely to experience dry eye, whereas those taking estrogen and progesterone have a 30 percent increased risk of developing dry eye.
Dry eye can also develop after the refractive surgery known as LASIK. These symptoms generally last three to six months, but may last longer in some cases.
Dry eye can result from chemical and thermal burns that scar the membrane lining the eyelids and covering the eye.
Allergies can be associated with dry eye.
Infrequent blinking, associated with staring at computer or video screens, may also lead to dry eye symptoms.
Both excessive and insufficient dosages of vitamins can contribute to dry eye.
Homeopathic remedies may have an adverse impact on a dry eye condition.
Loss of sensation in the cornea from long-term contact lens wear can lead to dry eye.
Dry eye can be associated with immune system disorders such as Sjögren’s syndrome, lupus, and rheumatoid arthritis. Sjögren’s leads to inflammation and dryness of the mouth, eyes, and other mucous membranes. It can also affect other organs, including the kidneys, lungs and blood vessels.
Dry eye can be a symptom of chronic inflammation of the conjunctiva, the membrane lining the eyelid and covering the front part of the eye, or the lacrimal gland. Chronic conjunctivitis can be caused by certain eye diseases, infection, exposure to irritants such as chemical fumes and tobacco smoke, or drafts from air conditioning or heating.
If the surface area of the eye is increased, as in thyroid disease when the eye protrudes forward or after cosmetic surgery if the eyelids are opened too widely, dry eye can result.
Dry eye may occur from exposure keratitis, in which the eyelids do not close completely during sleep.
Who is likely to develop dry eye?
Elderly people frequently experience dryness of the eyes, but dry eye can occur at any age. Nearly five million Americans 50 years of age and older are estimated to have dry eye. Of these, more than three million are women and more than one and a half million are men. Tens of millions more have less severe symptoms. Dry eye is more common after menopause. Women who experience menopause prematurely are more likely to have eye surface damage from dry eye. Dry eye in the twin cities is a common condition. We have the tools to detect sickness and treat it at every stage. Schedule an appointment online (visionsource-yankee.com / visionsource-rosemount.com) or over the phone at (651) 452-0344 or (651) 423-3300. Alternatively, you could stop by our Eagan or Rosemount offices for a walk-in examination.