The incorporation of nanocarriers into drug delivery systems for eye conditions is a potential development in targeted treatment and long-term medication release. The safety and toxicity issues surrounding the use of nanocarriers in ophthalmology are thoroughly examined in this chapter. By improving medication solubility, bioavailability, and targeted transport to the ocular tissues, nanocarriers such as liposomes, dendrimers, nanoparticles, and micelles have the potential to overcome the drawbacks of traditional ophthalmic therapies. Nevertheless, their distinct physicochemical characteristics give rise to serious questions regarding toxicity and biocompatibility, requiring in-depth analyses. With the aim to evaluate the toxicity characteristics of these nanocarriers, this chapter focuses on in vitro and in vivo investigations. To assess cellular reactions to nanocarriers, in vitro investigations include genotoxicity tests, oxidative stress indicators, and cytotoxicity assays. Acute and chronic toxicity, organ-specific toxicity, and pharmacokinetic behavior in animal models are all covered by in vivo evaluations. Size, surface charge, composition, and dose are some of the elements that affect the safety of nanocarriers. These factors are thoroughly examined to see how they may contribute to any harmful consequences. Other difficulties covered include immunological reactions, the requirement for standardized testing procedures, and the way in which nanocarriers interact with ocular tissues. This study emphasizes how crucial it is to conduct thorough safety evaluations and provide recommendations for the clinical application of nanocarriers in the transport of medications to the eyes. For these cutting-edge drug delivery technologies to be successfully applied in treating a variety of ocular disorders and, eventually, improve patient outcomes, their safety must be guaranteed.