Alcaine

A topical eye anesthetic is a topical anesthetic that is used to numb the surface of the eye. Examples of topical eye anesthetics are oxybuprocaine, tetracaine, alcaine, proxymetacaine and proparacaine. more...

Some topical eye anesthetics are also used in otolaryngology, like for example oxybuprocaine.

Use of topical eye anesthetics in ophthalmology

Topical eye anesthetics are used in ophthalmology in order to numb the surface of the eye (the outermost layers of the cornea and conjunctiva) for the following purposes:

• In order to perform a contact/applanation tonometry.
• In order to perform a Schirmer's test (The Schirmer's test is sometimes used with a topical eye anesthetic, sometimes without. The use of a topical eye anesthetic might impede the reliability of the Schirmer's test and should be avoided if possible.).
• In order to remove small foreign objects from the uppermost layer of the cornea or conjunctiva. The deeper and the larger a foreign object which should be removed lies within the cornea and the more complicated it is to remove it, the more drops of the topical eye anesthetic are necessary to be dropped onto the surface of the eye prior to the removal of the foreign object in order to numb the surface of the eye with enough intensity and duration.

Duration of topical eye anesthesia

The duration of topical eye anesthesia might depend on the type of the topical eye anesthetic and the amount of eye anesthetic being applied, but is usually about half an hour.

Abuse when used for pain relief

When used excessively, topical anesthetics can cause severe and irreversible damage to corneal tissues and even loss of the eye. The abuse of topical anesthetics often creates challenges for correct diagnosis in that it is a relatively uncommon entity that may initially present as a chronic keratitis masquerading as acanthamoeba keratitis or other infectious keratitis. When a keratitis is unresponsive to treatment and associated with strong ocular pain, topical anesthetic abuse should be considered, and a history of psychiatric disorders and other substance abuse have been implicated as important factors in the diagnosis. Because of the potential for abuse, clinicians have been warned about the possibility of theft and advised against prescribing topical anesthetics for therapeutic purposes.

Read more at Wikipedia.org