Topical administration is the greatest alternative for ocular medicines since it activates rapidly, doesn't cause systemic toxicity, and requires fewer doses than systemic use. The inner workings of the eye must be reached by drugs applied topically, and trans corneal penetration is assumed to be the primary route for drug absorption. Corneal absorption happens significantly more slowly than elimination. The specific objective of therapeutic system design is to attain the optimal drug concentration at the active site for the appropriate duration of time. The main obstacle to long-term ocular treatment is the capacity to maintain a therapeutic dosage of medication at the site of action. The ocular absorption mode of elimination is significantly slower. For many years, scientists have been interested in the problem of effective topical administration. Their challenging goal is to ensure proper ocular penetration and extend the drug's residence period.  Nanotechnology based carriers to ensnare both lipophilic and hydrophilic medicines, improve ocular permeability, prolong residence duration, stabilize pharmaceuticals and in vivo characterization techniques aid in the prediction of the generated nanocarriers' results. Clarifying the architecture of the eye, different ocular disorders, and barriers to ocular delivery are the goals of this review.