Nanotechnology in ocular delivery: current and future directions.

Our knowledge in the field of ocular drug delivery is rapidly expanding. An increase in the understanding of ocular drug absorption and disposition vis-à-vis developments in nanotechnology has led to the emergence of many of the nanotechnology-based ocular drug delivery systems including nanoparticles, microemulsions, liposomes, solid lipid nanoparticles, light-sensitive nanocarrier systems, etc. The need to develop effective treatments for posterior eye segment diseases is more important than surface delivery. Treatment of blinding diseases of the eye, such as proliferative retinopathy or macular degeneration, requires effective and safe delivery of drugs to posterior eye segment tissues, and recent advances in nanotechnology have demonstrated successful outcomes. Nanoscientists should focus their efforts on nano-ophthalmology. This review describes the current status and progress made so far, and the course that needs to be pursued in the future.