Subconjunctival/episcleral, intrascleral, and suprachoroidal routes of drug delivery for treatment of posterior
segment eye diseases have become more feasible and popular in the past few years. These routes have the advantage of
bypassing the main barriers to topical drug penetration, the ocular surface epithelium, the conjunctivallymphatics, and in
the case of deep intrascleral and suprachoroidial delivery, the sclera barrier. Many ocular drug delivery application devices,
drug delivery methods, and therapeutics that have been developed for intravitreal use can also be used subconjunctivally,
intrasclerally, and in the suprachoroidal space. Alternatively, site-specific devices, such microneedles, and therapeutics,
such as hydrogel matrices, have been developed to enhance ocular drug delivery. This manuscript will review the
recent research advances and patents on episcleral, intrascleral, and suprachoroidal routes of ocular drug delivery.