**6. Conclusion**

Drug distribution to ocular tissues has been a significant problem for ocular scientists for many years. The use of drug solutions as topical drops with conventional formulations had some drawbacks, prompting the development of new carrier systems for ocular delivery. Huge efforts are being made in ocular research to develop novel drug delivery strategies that are both safe and patient-friendly. Researchers are currently working hard to improve the in vivo performance of conventional formulations. On the other hand, ocular scientists are intrigued by the development of nanotechnology, innovative methods, gadgets, and their applications in drug delivery. Using invasive, non-invasive, or minimally invasive drug administration techniques, drug molecules are encapsulated in particulate or vesicular carrier systems or devices.

Contact lenses, in situ gels, microemulsions, niosomes, liposomes, implants, microspheres, and micelles are just a few of the nanotechnology-based carrier systems being developed and studied. A few of these are mass-produced commercially and used in clinical settings. The body of the patient gains from novel medication delivery methods by lowering drug-induced toxicity and visual loss. Additionally, these carriers or devices lengthen drug release, increase targeted moieties' specificity, and help reduce dose frequency. However, after non-invasive medication administration, a carrier system that can reach targeted ocular tissue, including the tissues in the rear of the eye, is still required to be developed. A topical drop formulation that maintains a high precorneal residence time, prevents non-specific drug tissue buildup, and delivers therapeutic drug levels into targeted ocular tissue is anticipated at the current rate of ocular research and development (both anterior and posterior). Invasive drug delivery techniques like intravitreal and periocular injections may one day be replaced by this delivery technology.
