Abstract: 
Ocular Drug Delivery (ODD) is an engrossing and challenging task for ‎pharmaceutical researchers. Unique anatomy and physiology of the eye poses ‎numerous challenges for designing targeted drug delivery systems. Ocular ‎discomfort involves the anterior and posterior segment diseases like glaucoma, ‎diabetic retinopathy, glaucomatous optic neuropathies, retinal vascular diseases, ‎posterior uveitis, and age-related macular degeneration that lead to distress, ‎inflammation and severe retinal disorders. Conventional treatments such as eye ‎drops, injections and implants suffer from a low ocular bioavailability due to ‎various anatomical and pathophysiological barriers. To deal with these problems ‎pharmaceutical researchers explored nanotechnology-based drug delivery ‎systems like polymeric and lipidic nanoparticles, liposomes, cubosomes, ‎nanoemulsions, niosomes, nanomicelles, dendrimers, microneedles, etc. These ‎nano-systems have achieved great success in solving the problems like drug ‎retention, bioavailability, sustained and targeted drug delivery without affecting ‎the eye tissues. This review provides an insight into recent advancements and the ‎emerging challenges for nanotechnology-based formulation development in the ‎area of ocular drug delivery and emphasizes applications of nanotechnology in ‎disease diagnostic in ophthalmology.‎

Keywords: Nanotechnology, Nanoparticle, Liposome, Hydrogel, Eye, Ocular Drug Delivery.