Effect
Inhibition of the sodium channel at the nerve tracts leads to a reduced action potential and thus to a reduced pain transmission. Anaesthetic eye drops are used in ophthalmology whenever the patient complains of pain-causing diseases. Corneal inflammations or injuries of the corneal surface can be very painful.
Also a longer, unprotected stay at high altitudes or in the sun or during welding work can cause very strong pain (keratoconjunctivitis photoelectrica). In this case, the patient should only be given the pain-relieving eye drops once and should not take them home with him/her, as once the effect has diminished, the patient would repeat the pain medication with the eye drops on his/her own and thus considerably prolong the recovery time. In daily ophthalmological practice, anaesthetic eye drops are also used to measure intraocular pressure, in which pressure is applied to the cornea with a small plastic vessel.
In this case, anaesthetic eye drops not only reduce the pain stimulus, but also the corneal reflex, which would not make this type of examination possible. The following eye drops are used:Oxybuprocaine (Conjucain, Novesine), Oxybuprocaine+fluorescein (Thilorbin), Proxymetacain (Proparacain-POS). All medications should be applied by 1 to 2 drops to the affected eye. The effect occurs within about 30 seconds.
Side effects
Prolonged use can lead to surface damage to the cornea and allergic reactions. The patient must also be told that the protective corneal reflex is reduced some time after the administration of the drops and that everyday activities, such as rubbing the eyes, can lead to injuries.
Contraindications
Known sensitivity and allergic reactions in the eye to the medication administered.
