TABLE 1.

Routes of administration and their benefits and profits.

Routes of Administration	Advantages	Disadvantages
Topical	Easy formulation	Frequent administration
	Patient-friendly (easy to apply)	Rapid wash out
	Efficient for anterior segment disorders	Difficulties to reach the posterior site
	Safe to use	Poor bioavailability
		Low retention time on the eye surface
		Limited volume of dosage form
		Restricted by corneal barrier and tear film barrier
		Blurred vision (ointment form)
Pre-ocular	Less-invasive (in comparison with intravitreal injection)	Low bioavailability
	Minor side effects	Restricted by ocular barriers
	Efficient for posterior segment drug delivery	Rapid wash out
	Deliver high amount of drugs to the target site	Risk of drug degradation
	Long duration of action
Intravitreal	Directly deliver the drugs to the posterior segment	Repeated injections
	Most efficient treatment for posterior segment	Invasive
		Numerous side effects
Systemic	Effective for the treatment of both anterior and posterior segments	Systemic side effects
		Restricted by blood ocular barriers (BRB and BAB)