What is Dry Eye?
Dry eye syndrome occurs when the eye does not produce tears properly (quantity), or when the tears are not of the correct consistency and evaporate too quickly (quality). Inflammation of the surface of the eye and eye lids may occur resulting in 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 for computer or reading, excessive sensitivity to light, and occasionally a sandy/gritty feeling in the eyes. 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.
The Cornea and the Tears
The cornea is the clear, dome-shaped outer surface. It helps protect the rest of the eye from germs, dust, and other harmful matter. It receives its nourishment from the tears. Tears, made by the lacrimal gland, are necessary for overall eye health, clear vision, and used to wash away dust and debris. They also help protect the eye from infections. Tears are composed of three parts:
A) outer, oily, lipid layer produced by the meibomian glands
B) watery, lacrimal layer produced by the lacrimal glands
C) inner, mucous or mucin layer produced by goblet.
Tears are made of proteins, electrolytes, and vitamins critical to maintaining the health of the eye and to prevent infection. 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.
Types of Dry Eye
1) Aqueous tear-deficiency: the lacrimal glands fail to produce enough of the watery component of tears
2) Evaporative dry eye: 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 but not limited to:
- inflammation of the surface of the eye, the lacrimal gland, or the conjunctiva
- any disease that alters the components of the tears; Arthritis is one of the most common
- an increase in the surface of the eye, as in thyroid disease when the eye protrudes forward, or if the lid does not completely close specifically at night.
- After cosmetic surgery, if the eyelids are opened too widely.
- Widely considered the most common side effect of lasik surgery
Dry Eye Symptoms
- stinging or burning
- sandy or gritty
- excess tears
- 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, computer; eye fatigue.
Dry Eye Causes
- 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
- Diseases of the glands in the eyelids, such as meibomian gland dysfunction, can cause dry eye.
- Pregnancy, and hormone replacement
- Refractive surgery known as LASIK; cosmetic surgery of lids...
- chemical and thermal burns that scar the membrane lining the eyelids
- Infrequent blinking associated with staring at a computer or video screens.
- long-term contact lens wear
- Immune system disorders such as Sjögren's syndrome, lupus, and rheumatoid arthritis
- Thyroid disease or
- Incomplete lid closure during sleep.
Dry Eye Treatment
Dry eye can be managed as an ongoing condition. The first priority is to determine if a disease is the underlying cause. If so, then the underlying disease needs to be treated.
Warm compresses and lid massage may be used with a steamy hot wash cloth or flack seed pillow. This causes the glands along the lids to expresses their contents allowing them to aid in production of normal, healthy tears.
Cyclosporine (Restasis), an anti-inflammatory medication, is the only prescription drug available to treat dry eye. It decreases corneal damage, increases basic tear production, and reduces symptoms of dry eye. It may take three to six months of twice-a-day dosages for the medication to work. Short term use of corticosteroid eye drops that decrease inflammation is also used.
If contact lens wear is the problem, another type of lens or reduction of wear time may improve symptoms. If the condition is severe enough, contact lenses may be discontinued altogether.
Allow your eyes to rest when performing activities that require you to use your eyes for long periods of time. Instill lubricating eye drops while performing these tasks, especially pertaining to computer use.
Another option is to plug the drainage canals, where tears drain from the eye. Punctal plugs can be inserted. The plugs are made of silicone or collagen. In some cases, punctal cautery is used to permanently close canals.
In some patients with dry eye, supplements or dietary sources (such as tuna fish) of omega-3 fatty acids (especially DHA and EPA) may decrease symptoms of irritation. The use and dosage of nutritional supplements and vitamins should be discussed with your primary medical doctor.
Use artificial tears, gels, gel inserts, and ointments - available over the counter - as the first line of therapy. Avoid artificial tears with preservatives if continued issues or preparations with chemicals that cause blood vessels to constrict.