Drugs acting on the eye
Drugs acting on the eye are used to treat a variety of disorders affecting the eye.
Many eye disorders can be treated by applying drugs directly to the eye in the form of eyedrops (see Using eyedrops) or ointments. Minor eye problems, such as dryness or irritation due to allergy, can often be relieved with over-the-counter remedies. Drugs for eye infections and for other serious conditions, such as uveitis or scleritis, in which the eye is inflamed, are available only on prescription.
|Anti-infective drugs: Aciclovir, Chloramphenicol, Ciprofloxacin, Gentamicin, Neomycin, Polymyxin B||Anti-inflammatory drugs: Betamethasone, Dexamethasone, Emedastine, Nedocromil sodium, Prednisolone, Sodium cromoglicate|
|Artificial tears: Carmellose, Hydroxyethylcellulose, Hypromellose, Polyvinyl alcohol||Mydriatics: Atropine, Cyclopentolate, Phenylephrine|
What are the types of drugs acting on the eye?
The main types of drug used to treat eye disorders are anti-infective drugs and anti-inflammatory drugs. Anti-infective drugs are commonly used to treat bacterial, viral, and, less commonly, fungal infections of the eye. Anti-inflammatory drugs are used to relieve the redness and swelling that may develop as a result of infection, allergic reactions, or autoimmune disorders (in which the immune system attacks the body's own tissues). Artificial tears are used to relieve dryness of the eyes (see Keratoconjunctivitis sicca). Mydriatrics dilate (widen) the pupil and are commonly used to treat uveitis.
There are two main groups of drugs used to treat eye infections. Antibiotics, such as chloramphenicol, may be used to treat bacterial infections such as conjunctivitis and blepharitis.
Antiviral drugs, such as aciclovir, are used to treat corneal ulcers that occur as a result of infection with herpes viruses.
Antibiotics are usually applied as eyedrops or ointment directly on to the site of infection in the eye. However, if a bacterial infection is severe, it may be necessary to take oral antibiotics as well as using eyedrops. Viral infections of the eye may be treated with both antiviral eyedrops and oral antiviral drugs.
When using antibiotic eyedrops or ointment, you may experience temporary stinging or itching. You may also notice a bitter taste as the eyedrops run down inside the tear ducts and into your nose and mouth. Medication in the form of eye ointment may have a longer-lasting effect than if applied as eyedrops. To reduce the risk of contaminating the eye, always wash your hands before applying the ointment and do not touch the affected eye with your fingers or the tube.
Corticosteroids are applied as eyedrops or as ointment squeezed just inside the eyelids. If you are predisposed to develop chronic glaucoma, in which the pressure of fluid in the eye becomes abnormally high, the use of corticosteroids may slightly increase your risk of developing drug-induced glaucoma. Corticosteroids are available on prescription and must be used under the supervision of a doctor.
Short-term inflammation caused by allergy is often treated with antihistamine or sodium cromoglicate eyedrops. Some antiallergy eyedrops, such as those used to treat eye irritation associated with hay fever (see Allergic rhinitis), are available over the counter. Antiallergy drugs may cause side effects such as blurred vision and headache.
Artificial tears drugs
Eyedrops containing chemicals to relieve dryness are available for people whose eyes do not produce enough natural tear fluid. Artificial tears form a moist film on the cornea (the transparent front part of the eye), soothing and rehydrating the surface of the eyes. You can buy artificial tear preparations over the counter. They may be applied as often as necessary.
These drugs are used to treat uveitis, an inflammatory condition affecting the iris (the coloured part of the eye) and the muscles that control focusing. If the iris becomes inflamed, there is a danger that it may stick to the lens of the eye. Most mydriatics, such as atropine and cyclopentolate, relax the ring of muscles in the iris, causing dilation of the pupil. Mydriatics may also be used to dilate the pupil during eye examinations and eye surgery.
Mydriatics are usually prescribed as eyedrops or eye ointment. While using a mydriatic drug, you may find that bright lights cause discomfort, and you may also have difficulty in focusing. These drugs can cause contact dermatitis and various other side effects, including dry mouth, constipation, and difficulty in passing urine. Certain mydriatics, such as phenylephrine, can also raise blood pressure and are therefore unsuitable for people who have high blood pressure (see Hypertension).
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