Essential topical ocular diagnostic drugs for the family practitioner

Abstract

may also be used. Always be aware that the minims are preservative free and because fluorescein is a growth medium for bacteria, once opened the container should be discarded within 24 hours. A few blinks spread the now-visible tear film across the cornea. No systemic complications accompany the use of topical fluorescein, but soft contact lenses may be permanently stained because of its porous structure. This may be avoided by first removing contact lenses before instillation of the dye. Fluorescein dye is indispensable for the detection of corneal conditions such as abrations, ulcers, herpetic disease, contact lens overwear and dry eye syndrome. Anaesthetics Among the topical anaesthetics, the most widely used agents are proparacaine hydrochloride 0.5%, benoxinate 0.5% and tetracaine 0.5%. The instillation of 1 drop of these surfaceactive compounds renders the corneal epithelium insensate within 15 seconds. Reapplication will enhance the anaesthetic effect. Such anaesthesia is useful to make surface manipulations painless such as removal of corneal or conjunctival foreign bodies, performing tonometry or giving a subconjunctival injection. Use of an anaesthetic also facilitates the examination of a damaged cornea which otherwise might be difficult because of the pain and accompanying blefarospasm. Patients should be advised not to rub their eyes after receiving such drops to prevent them from inadvertently scratching their corneas. Never prescribe topical anaesthetics for repeated use by patients because they are toxic to the corneal epithelium; they inhibit mitosis and cellular migration and can lead to corneal ulceration and permanent corneal scarring.