When are parabulbar injections prescribed?
This is the most common method of delivering the drug to the posterior segment of the eye. Injections are used for retinal dystrophy, optic nerve atrophy, diabetic retinopathy, retinal vein thrombosis, inflammatory diseases and after injuries. The needle is inserted through the lower eyelid into the fatty tissue of the orbit; the eyeball itself is not pierced. Usually a course of 5–10 injections is prescribed daily or every other day.
Why is the drug injected into the eye?
The eye is separated from the general bloodstream by a blood-ophthalmic barrier: the medicine taken in tablets reaches the retina in a negligible concentration. Therefore, local administration is widely used in ophthalmology - drops, injections under the conjunctiva, parabulbar, retrobulbar and directly into the vitreous body.
The deeper the drug is injected, the higher the concentration in the desired area, but the stricter the requirements for sterility and technique.
Types of drug administration
- subconjunctival - under the mucous membrane of the eye
- parabulbar - in the tissue around the eyeball
- retrobulbar - behind the eyeball, closer to the optic nerve
- intravitreal - directly into the vitreous body
What is important for the patient to know
Injections are performed after instillation of anesthetic drops, so pain is minimal. A slight hemorrhage under the conjunctiva after an injection is a common and safe occurrence; it resolves in 1–2 weeks. You should consult a doctor if pain increases, vision decreases, and redness increases a day after the procedure.