Allergic diseases of eye, especially allergic conjunctivitis is very common.
The following forms of allergic eye diseases are present:
- Allergic conjunctivitis
- Atopic keratoconjunctivitis
- Spring-time conjunctivitis
- Contact dermatitis of eyelids and contact dermatoconjunctivitis
The first three forms comprise 84% of allergic disorders of eyes. Despite each disease has its characteristic anamnesis, clinical expression and histological signs, each one has allergic basis. In the patients with eye allergy all those diseases that have alike symptoms should be excluded: Staphylococcal infection, blepharoconjunctivitis, acute viral conjunctivitis, Chlamydial conjunctivitis, Herpetic and dry keratoconjunctivitis.
According to its anatomic characters conjunctiva actively participates in immune processes and is the main border between internal and external environment.
There are various immune competent cells (lymphocytes, neutrophils, plasma cells) in the conjunctiva, which take part in antigen processing and neutralization. There are two types of mast cells in conjunctiva, superficial tryptase containing cells and both tryptase and chymase containing mast cells (the later predominates in healthy conjunctiva and is not dependent on T lymphocytes).
In epithelial and subepithelial layer number of only tryptase containing mast cells increase during seasonal and non seasonal conjunctivitis. Also increases titer of inflammatory mediators (Histamine, Leukotrienes, PGD2, Tryptase, Carboxypeptidase A, Catepsin G and PAF). These factors determine clinical picture of allergic conjunctivitis, characterized by itching, conjunctival injection, lacrimation, soreness, photophobia etc.
Seasonal type is more prevalent and it can also be accompanied by allergic rhinitis. The reason is presence of seasonal aeroallergens (usually plant dust). 78% of the patients have high titers of specific Ig E . Duration of the allergic conjunctivitis seasonal type depends on the duration of allergic plants’ fruition.
Non seasonal type is less frequent. Mite dust, animal epidermis and bird feather is the main cause. Although this type of conjunctivitis has no seasonal variation , it may have seasonal exacerbations.
Hypersensitivity reaction during allergic conjunctivitis may have early and late phases both mediated by mast cells. Immediate hypersensitivity occurs in 20 minutes after allergen encounter and Tryptase and Histamine levels increase dramatically. Delayed phase develops 6 hours after allergen encounter, during which Histamine levels increase again but Tryptase and number of basophils doesn’t increase. Cellular infiltrate is made of mast cells, eosinophils, neutrophils and macrophages. Number of cell adhesion molecules (E-selectins, P-selectins etc) increase explained by participation of neutrophils and eosinophils in the delayed phase.
Drugs of various pharmacologic groups are used in treatment of allergic conjunctivitis, because of their superiorities toward one another. Antihistamine medications in pill and capsule forms are easy to take and very effective for accompanied allergic rhinitis. But antihistamine therapy need supplementation of other medications, because of antihistamine drug side effects (conjunctival dryness, systemic effects etc).
Local anti-histamines and sympathomimetics are effectively used minimizing systemic effects. In case of overdose they cause refractory drug induced conjunctivitis, persisting even after drug removal.
NSAIDs are effective for itching and pain, but they can’t be used in patients sensitive to Aspirin.
Corticosteroids are useful only for short-term treatment periods, they increase intraocular pressure and predispose to development of infective conjunctivitis and keratitis.
Mast cell stabilizing agents suppress early and delayed phases of allergic reactions and are safe with regard of side effects. They achieve clinical benefits after 2-5 days and maximal efficiency in 15 days.
EYECROL (sodium cromoglycate) is very successful in ophthalmology practice. It inhibits mast cell degranulation and interferes with release of allergic mediators.
4% sol of EYECROL is effective and well tolerable for patients. Start of treatment is recommended before beginning of the season. Regular use of the medication determines fast achievement of clinical benefits of the therapy. EYECROL can also be used immediately before inevitable encounter with the allergens (before entering house with pets).
EYECROL is also very effective for Dry eye Syndrome, eye strain, occupational disorders, long-time computer work.
Regarding EYECROL pharmacologic actions, it is very effective and safe medication for treatment and prophylaxis of allergic eye diseases.
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