Intravitreal Injection in Practice: Review

Intravitreal injection is the method of administration of drugs into the eye by injection with a needle; the medication will be directly applied into the vitreous body. Compared to topical administration, this method is allows to deliver medications to the targeted site, as the needle can directly pass through the anatomical eye barrier (e.g. cornea, conjunctiva and lens) and dynamic barrier (e.g. tears and aqueous humor). It could also minimize adverse drug effect to other body tissues via the systemic circulation, which could be a possible risk for intravenous injection of medications. Intravitreal injection was first mentioned in a study in 1911, in which the injection of air was used to repair a detached retina. Intravitreal injection has become more common and a surge in the number of injections performed could be seen. The risk of complications can be minimized if all prescriptions are followed. This article presents in detail the intravitreal injection technique, pre-treatment and post-treatment precautions. Also in this article describes ocular drug delivery systems which provide controlled release for the treatment of chronic diseases, and increase patient’s and doctor’s convenience to reduce the dosing frequency and invasive treatment.