Medicinal products promoted, recommended or marketed for use as eye-drops or eye ointments are not available for general sale - they are all classified as pharmacy medicines. Ophthalmic complaints did not feature as one of the top 10 ailments for self-treatment recently. There are a number of eye disorders which may be treated by over-the-counter (OTC) preparations.
Conjunctivitis is the first condition that is discussed over here. This disorder is an inflammation of the mucous membrane that lines the eyelids and covers the anterior surface of the eye (excluding the cornea). Conjunctivitis may result from microbial infection or be allergic in origin. Both types are amenable to treatment with OTC preparations. It can be of two types:
1. Infective conjunctivitis: This can be bacterial, viral, chlamydial or fungal in origin. Staphylococcus species are the most common infecting bacteria, but others include streptococcus and haemophilus species.Viral infection may be caused by adenovirus and Herpes simplex virus. Chlamydial infection causes trachoma, which is the greatest cause of preventable blindness worldwide. Fungal conjunctivitis is rare but may be encountered in rural areas.
Sign and symptoms: Infective conjunctivitis is characterised by a diffuse redness of the conjunctiva with a purulent (bacterial) or watery (viral) discharge. Viral infections are commonly associated with upper respiratory tract infections and swollen pre-auricular nodes.
Most cases of infective conjunctivitis are self-limiting but can be treated with the antimicrobials. The aim of antimicrobial therapy is to achieve a concentration of the antimicrobial agent at the site of infection high enough to kill or stop the growth of the infecting organism.
2. Allergic conjunctivitis: Several types of hypersensitivity reactions in the eye are recognised. Those amenable to treatment with OTC medicines are of the immediate hypersensitivity type and include acute allergic conjunctivitis, seasonal or hay fever conjunctivitis and vernal keratoconjunctivitis.
In all cases, the disease process is thought to be initiated by allergens combining with immunoglobulin E which is bound to conjunctival mast cells. This interaction causes mast cell degranulation leading to the release of numerous chemical mediators, such as histamine. These mediators trigger the inflammatory cascade, resulting in vasodilatation, increased vascular permeability and oedema and give rise to the classical symptoms of allergic conjunctivitis.
Sign and symptoms: Hyperaemia (redness), Eyelid swelling, Puffy eyelids, Peripheral corneal vascularisation, Itching and burning, Lachrymation, Foreign body sensation, Stinging, Watery discharge, Photophobia,
Preparations used to treat allergic conjunctivitis contain mast cell stabilisers, antihistamines, sympathomimetics and astringents.
