Dry Eye Syndrome
Normal vision requires a moist healthy ocular surface. A sufficient quality of tears, a normal composition of the tear film, normal lid closure, and regular blinking are among the prerequisites to maintain a healthy ocular surface.
What is Dry Eye?
Dry eye is a disorder of the tear film due to tear deficiency or excessive tear evaporation which causes damage to the interpalpebral ocular surface (i.e. exposed eye surface) and is associated with symptoms of ocular discomfort. This definition of dry eyes was adopted by the National Eye Institute workshop on dry eyes.
The eye becomes dry either because there is not enough tears being produced or because there is abnormally high rate of evaporation of tears.
In the light of new knowledge about the roles of tear hyperosmolarity and ocular surface inflammation in dry eye and the effects of dry eye on visual function, The Dry Eye Workshop (DEWS) in 2007 adopted a revised definition of dry eyes. According to the DEWS definition, Dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface. Dry eye is recognized as a disturbance of the Lacrimal Functional Unit (LFU), an integrated system comprising the lacrimal glands, ocular surface (cornea, conjunctiva and meibomian glands) and lids, and the sensory and motor nerves that connect them (Link fo DEWS Report).
According to the DEWS report, prevalence of dry eye ranges from 5%-30% in people aged 50 years and older. Prevalence of moderate- to-severe dry eye lies closer to the lower estimate of the range, whereas prevalence of mild dry eyes lies closer to the higher estimate of the range. It is estimated that about 3.2 million women and 1.7 million men, for a total of 4.9 million Americans 50 years and older have dry eye. Tens of millions more have mild dry eyes that may be notable only when some adverse contributing factor is present, such as low humidity or contact lens wear.
Normal vision requires a moist healthy ocular surface. A sufficient quality of tears, a normal composition of the tear film, normal lid closure, and regular blinking are among the prerequisites to maintain a healthy ocular surface.
What is Dry Eye?
Dry eye is a disorder of the tear film due to tear deficiency or excessive tear evaporation which causes damage to the interpalpebral ocular surface (i.e. exposed eye surface) and is associated with symptoms of ocular discomfort. This definition of dry eyes was adopted by the National Eye Institute workshop on dry eyes.
The eye becomes dry either because there is not enough tears being produced or because there is abnormally high rate of evaporation of tears.
In the light of new knowledge about the roles of tear hyperosmolarity and ocular surface inflammation in dry eye and the effects of dry eye on visual function, The Dry Eye Workshop (DEWS) in 2007 adopted a revised definition of dry eyes. According to the DEWS definition, Dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface. Dry eye is recognized as a disturbance of the Lacrimal Functional Unit (LFU), an integrated system comprising the lacrimal glands, ocular surface (cornea, conjunctiva and meibomian glands) and lids, and the sensory and motor nerves that connect them (Link fo DEWS Report).
According to the DEWS report, prevalence of dry eye ranges from 5%-30% in people aged 50 years and older. Prevalence of moderate- to-severe dry eye lies closer to the lower estimate of the range, whereas prevalence of mild dry eyes lies closer to the higher estimate of the range. It is estimated that about 3.2 million women and 1.7 million men, for a total of 4.9 million Americans 50 years and older have dry eye. Tens of millions more have mild dry eyes that may be notable only when some adverse contributing factor is present, such as low humidity or contact lens wear.
Although most people equate dry eye disease with uncomfortable eyes, serious vision complications are a distinct possibility. If untreated severe dry eye disease may lead to desiccation of the corneal epithelium, ulceration and perforation of the cornea, an increased incidence of infectious disease, and, potentially, serious visual impairment and blindness. Therefore the diagnosis and adequate treatment of dry eyes is important.
There have been several recent developments of significance. It is now being realized that part of the problem in dry eye disease is a low grade (subclinical) inflammation. The use of anti-inflammatory agents (mild steroids or cyclosporine eye drops) may help these patients. The effect of androgen deficiency is also being studied since majority of dry eye disease suffers are females.
There have been several recent developments of significance. It is now being realized that part of the problem in dry eye disease is a low grade (subclinical) inflammation. The use of anti-inflammatory agents (mild steroids or cyclosporine eye drops) may help these patients. The effect of androgen deficiency is also being studied since majority of dry eye disease suffers are females.
What are the Symptoms of Dry Eye?
The usual symptoms include:
- stinging or burning eyes
- scratchiness
- stringy mucus in or around the eyes
- excessive eye irritation from smoke or wind
- excess tearing
- difficulty wearing contact lenses
Excess tearing from Dry Eye sounds illogocal, but if the tears responsible for maintenance lubrication do not keep the eye wet enough, the eye becomes irritated. When the eye is irritated, the lacrimal gland produces a large volume of tears that overwhelm the tear drainage system. These excess tears then overflow from your eye.
What is the Tear Film?
A film of tears, spread over the eye by a blink, gives the eye a glassy smooth optical surface. Without a healthy tear film, good vision is not possible.
The tear film consists of 3 layers:
The usual symptoms include:
- stinging or burning eyes
- scratchiness
- stringy mucus in or around the eyes
- excessive eye irritation from smoke or wind
- excess tearing
- difficulty wearing contact lenses
Excess tearing from Dry Eye sounds illogocal, but if the tears responsible for maintenance lubrication do not keep the eye wet enough, the eye becomes irritated. When the eye is irritated, the lacrimal gland produces a large volume of tears that overwhelm the tear drainage system. These excess tears then overflow from your eye.
What is the Tear Film?
A film of tears, spread over the eye by a blink, gives the eye a glassy smooth optical surface. Without a healthy tear film, good vision is not possible.
The tear film consists of 3 layers:
The oily layer, produced by the eyelid`s Meibomian Glands, forms the outermost surface of the tear film. Its main purpose is to smooth the tear surface and reduce evaporation of tears.
The inner layer consists of mucus produced by the conjunctiva, the paper-thin mucous membrane that covers the surface of the eyeball. Mucus allows the watery layer to spread evenly over the surface of the eye and helps the eye remain moist. Without mucus, tears would not stick to the eye.
What causes Dry Eye?
Tear production normally decreases as we age. Although dry eye can occur in both men and women at any age, women are most often affected. This is especially true after menopause.
Dry eye also can be associated with other problems. For example, people with dry eyey, dry mouth and arthritis are said to have Sjogren`s syndrome.
A wide variety of common medications, prescriptions and over-the-counter can cause dry eye by reducing tear secretion. Be sure to tell us the names of all the medications you are taking, especially if you are using:
- diuretics
- beta-blockers
- antihistamines
- sleeping pills
- medications for "nerves"
- pain relievers
Since these medications are often necessary, the dry eye condition may have to be tolerated or treated with "artificial tears."
People with dry eye are often more prone to the toxic side effects of eye medications, including artificial tears. For example, the preservatives in certain eye drops and artificial tear preparations can irritate the eye. Special preservative-free artificial tears may be required.
How is Dry eye diagnosed?
We usually are able to diagnose dry eye by examining the eyes. Sometimes tests that meansure tear production may be necessary. One test, called the Schirmer tear test, involves placing filter-paper strips under the lower eyelids to measure the rate of tear production under various conditions. Another uses a diagnostic drop (fluorescein or rose bengal) to look for certain patterns of dryness on the surface of the eye.
How is Dry Eye treated?
Artificial tears are available without prescription. There are many brands on the market, so you may want to try several to find the one you like best.
Preservative-free eye drops are available if you are sensitive to the preservatives in artificial tears. If you need to use artificial tears more than every 2 hours, preservative-free brands may be better for you.
Tears drain out of the eye through a small channel into the nose (which is why your nose runs when you cry). We may close these channels either temporily or permanently. The closure conserves your own tears and makes artificial tears last longer.
A tear plug is in place in the lower eyelid drainage duct. Natural tears are retained rather than drained away, allowing more natural lubrication for the eye.
What causes Dry Eye?
Tear production normally decreases as we age. Although dry eye can occur in both men and women at any age, women are most often affected. This is especially true after menopause.
Dry eye also can be associated with other problems. For example, people with dry eyey, dry mouth and arthritis are said to have Sjogren`s syndrome.
A wide variety of common medications, prescriptions and over-the-counter can cause dry eye by reducing tear secretion. Be sure to tell us the names of all the medications you are taking, especially if you are using:
- diuretics
- beta-blockers
- antihistamines
- sleeping pills
- medications for "nerves"
- pain relievers
Since these medications are often necessary, the dry eye condition may have to be tolerated or treated with "artificial tears."
People with dry eye are often more prone to the toxic side effects of eye medications, including artificial tears. For example, the preservatives in certain eye drops and artificial tear preparations can irritate the eye. Special preservative-free artificial tears may be required.
How is Dry eye diagnosed?
We usually are able to diagnose dry eye by examining the eyes. Sometimes tests that meansure tear production may be necessary. One test, called the Schirmer tear test, involves placing filter-paper strips under the lower eyelids to measure the rate of tear production under various conditions. Another uses a diagnostic drop (fluorescein or rose bengal) to look for certain patterns of dryness on the surface of the eye.
How is Dry Eye treated?
- Adding Tears
Artificial tears are available without prescription. There are many brands on the market, so you may want to try several to find the one you like best.
Preservative-free eye drops are available if you are sensitive to the preservatives in artificial tears. If you need to use artificial tears more than every 2 hours, preservative-free brands may be better for you.
- Conserving the Tears
Tears drain out of the eye through a small channel into the nose (which is why your nose runs when you cry). We may close these channels either temporily or permanently. The closure conserves your own tears and makes artificial tears last longer.
A tear plug is in place in the lower eyelid drainage duct. Natural tears are retained rather than drained away, allowing more natural lubrication for the eye.
- Other methods
Anything that may cause dryness, such as an overly warm room, hair dryers or wind, should be avoided by a person with dry eye. Smoking is especially bothersome.
Some people with dry eye complain of "scratchy eyes" when they wake up. This symptom can be treated by using an artificial tear ointment or thick eye drops at bedtime. Use the smallest amount of ointment necessary for comfort, since the ointment can cause your vision to blur.
Dry eye due to lack of vitamin A in the diet is rare but is more common in poorer countries, expecially among children. Ointments containing vitamin A can help dry eye if it is caused by unusual conditions such as Steven.Johnson syndrome or pemphigoid. Vitamin A supplements do not seem to help people with ordinary dry eye.