your eyes are red, sting or you have a foreign body sensation and itching in
the eyes - that may be a sign for Dry Eye Disease. The eyes may also be
sensitive to light or feel tired, even painful. Sometimes there may be tearing
too, a reflexive production of tears when the eye becomes irritated. Also
blurring of vision is possible.
Symptoms of dry eye are more frequent in females and elderly people. It is
estimated that more than 15% of people, who are 55 years or above, have some
kind of dry eye disease.
Dry eye disease
(equivalents are: keratoconjunctivitis sicca or just dry eye) occurs, when
there is a problem with the tear film that normally keeps the eyes moist and
lubricated: either tear fluid is no longer produced in sufficient quantity, the
quality of tear fluid has changed or tear fluid is evaporated to an exceptional
If tear fluid is
produced insufficiently, the underlying reason is normally a dysfunction of the
lacrimal gland (a gland which produces tears, lying within the orbit on the
outer portion of the upper eye). Increased evaporation of tear fluid may have
various causes, such as diseases of the meibomian glands (located at the rim of the eyelids),
disorders of lid aperture, low blink rate, etc.
The tear film keeps the eye moist, cleans the eye surface and provides protection from injury and infection. It is evenly distributed through the blinking of the eyelid, which happens about every 5 to 10 seconds. The tear film has three distinct layers, which all have their own purpose:
The lipid (oily) layer, produced by the meibomian glands, forms the outermost surface of the tear film. Its main function is the protection of the aqueous layer from evaporation. It also prevents the tears from spilling out of the eye and stabilises the tear film.
The aqueous (watery) layer makes up most of what we ordinarily think of as tears. This layer is produced by the lacrimal glands. It supplies the corneal epithelium with nutrients and atmospheric oxygen and has antibacterial effects. It also cleanses the ocular surface, washing away debris and bacteria.
This inner layer of the tear film consists of mucus produced by the conjunctiva. It considerably decreases the surface tension. Moreover, it permits the easy and even spread of the aqueous layer on the cornea, which is important for a sharp image on the eye.
Dry eye disease
has various causes, such as:
see an ophthalmologist for further examination. The doctor may color the
surface of your eyes with a dye to see, whether he can detect a typical
coloring on the cornea. Or he may use the Schirmer test (a paper slip is put on
the inside of the lower eyelids, which is wetted with tear fluid) to measure
the tear production of the eye. If the result clearly deviates from the
reference, the tear production is disturbed.
of treatment is to alleviate the symptoms of dry eye disease. Dry eyes are
treated usually with tear substitutes, which lubricate the surface of the eye. They
often have to be applied several times per day. Other treatments beside the tear substitutes may include ciclosporin, puntal plugs etc. If the use is chronic or frequent, you wear
contact lenses or are sensitive to the preservative used in most eye drops, you
should resort to preservative-free products.