27 سنوات
Why my eyes are always dry ? even if I use natural tears ? is there an effective medicine?
9 سبتمبر 2014
If not properly managed, this condition can result 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 hinder the performance of some activities, such as using a computer or reading for a prolonged period of time, and it can reduce tolerance for dry environments, such as the air inside an airplane.
Other names for dry eye include dysfunctional tear syndrome, lacrimal keratoconjunctivitis, evaporative tear deficiency, aqueous tear deficiency, and LASIK-induced neurotrophic epitheliopathy (LNE).
There are two types of dry eye:
1) Aqueous tear-deficient dry eye: the lacrimal glands (the tear producing glands) do not produce enough of the watery component of tears to properly lubricate the eye surface and keep it in good health.
2) Evaporative dry eye: could happen in the context of inflammation of the meibomian glands, also located in the eyelids. These glands produce the lipid or oily part of tears that slows down evaporation and keeps the tears stable.
Tears, produced by the lacrimal gland, contain proteins (including growth factors), electrolytes, and vitamins that are essential to maintain an overall healthy eye and clear vision. Tears bathe the surface of the eye, keeping it moist, and wash out any dust particles or debris that may fall onto that surface. They also help protect the eye from infections.
Tears are made up of three major ingredients:
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 (these cells are found within a thin transparent layer over the white part of the eye and covering the inner surface of the eyelids).
Tears are produced at a baseline level to bathe, nourish, and protect the eye surface. They are also produced in response to certain triggers or noxious stimuli, 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.
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.
• stinging or burning of the eye;
• a sandy or gritty feeling as if there’s a foreign body in the eye (the feeling is especially prominent when you blink or close your eyes, as if you’re closing them onto an object);
• episodes of excess tears following very dry eye periods;
• discharge from the eye;
• pain and redness of the eye;
• episodes of blurred vision;
• heavy eyelids;
• 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;
• eye fatigue.
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Dry eye can be either a temporary or a chronic condition:
• Medications side effect, including antihistamines, nasal decongestants, tranquilizers, and anti-depressants.
• Skin disease: on or around the eyelids
• Diseases of the glands in the eyelids, such as meibomian gland dysfunction
• Pregnancy
• Hormone replacement therapy (in women)
• Post LASIK surgery, the refractive surgery; usually takes an average of three to six months to resolve, but may last longer in some cases.
• Chemical and thermal burns (due to occupational exposure) that scar the membrane lining the eyelids and covering the eye.
• Allergies
• Infrequent blinking, due to staring at computer or video screens
• Excessive or insufficient vitamins
• Homeopathic remedies
• Loss of sensation in the cornea associated with long-term contact lens wear.
• Some auto immune system disorders such as Sjögren's syndrome, lupus, and rheumatoid arthritis.
• Chronic inflammation of the conjunctiva, the thin transparent 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.
The approach to treatment id decided based upon the underlying cause(s). In order to identify the cause, you need to consult your ophthalmologist and optician.
Primarily, the possibility of an underlying pathological cause, such as Sjögren's syndrome or lacrimal and meibomian gland dysfunction, must be ruled out, in order to institute treatment it if need be.
Cyclosporine, an anti-inflammatory medication, is the only prescription drug available to treat dry eye. It reduces corneal damage, stimulates basic tear production, and alleviates symptoms of dry eye. It may require three to six months of twice-a-day dosages for the medication to work. Some patients with severe dry eye may benefit from a short term course of corticosteroid eye drops that function by counteracting inflammation.
If dry eye is secondary to a particular medication, your doctor may offer an alternative treatment with no such side effect profile.
If contact lens wear is the problem, you may need to use another type of lens or minimize the number of hours you wear your lenses. In the case of severe dry eye, you may have to ditch wearing contact lenses all together.
Another option is to plug the drainage holes, small circular openings at the inner corners of the eyelids where tears drain from the eye into the nose. This procedure is also known as punctal plugs, which can be inserted painlessly, and you usually do not feel they are present in your eye. These plugs are made of silicone or collagen, are removable, and are a temporary measure. In severe cases, permanent plugs may be considered.
In some cases, a simple surgery, called punctal cautery, is recommended to permanently close the drainage holes. This helps trap the limited volume of tears on the eye surface for a longer period of time before it gets drained out.
In some patients with dry eye, supplements or dietary sources (such as tuna fish) of omega-3 fatty acids (especially DHA and EPA) may help reduce the symptoms of irritation.
Meanwhile, you can do the following, in addition to the use of artificial tears (note that you ought to choose artificial tears without preservatives or chemicals that cause blood vessels to constrict if you need to apply them more than four times a day)
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• Wear glasses or sunglasses that fit close to the face (wrap around shades) or that have side shields, these can partially reduce tear evaporation from the eye surfaces.
• Use an air cleaner or a humidifier to filter dust and keep the air moist.
• Avoid dry conditions
• Give your eyes periods of rest when performing activities that require you to use your eyes for long periods of time, and frequently apply artificial tears while performing these tasks
• Minimize the use of contact lenses, especially when performing such activities.
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