Nanotechnology Systems in Drug Delivery to the Anterior Segment of the Eye—A Narrative Review of the Latest Preclinical Research Results

Background: Eye diseases represent a significant public health problem. The effectiveness of ophthalmic pharmacotherapy largely depends on efficient drug delivery to the eye tissues. Conventional eye drops exhibit low bioavailability due to anatomical and physiological barriers. Nanotechnology offers novel strategies to enhance drug penetration, retention, and controlled release within the anterior segment of the eye. This study aimed to systematically analyze preclinical research on the use of nanocarriers in drug delivery to the anterior segment. Methods: A literature review was conducted using PubMed, Scopus, and Google Scholar databases, covering English-language publications from 2019 to 2025. Preclinical studies evaluating nanocarriers for the treatment of anterior segment eye diseases and available in full text were included. Results: The analyzed studies indicate that nanocarriers, including solid lipid nanoparticles, nanostructured lipid carriers, nanomicelles, and polymeric nanoparticles, enhance drug bioavailability by improving mucoadhesion, facilitating penetration through the corneal epithelium, and prolonging ocular surface retention time. Key physicochemical parameters include small particle size, low polydispersity index, appropriate zeta potential, and high encapsulation efficiency. Preclinical models demonstrated improved therapeutic outcomes, including greater intraocular pressure reduction in glaucoma, increased tear production in dry eye syndrome, and enhanced anti-inflammatory and antifungal effects compared with conventional preparations. Conclusions: Nanotechnology-based drug delivery systems represent a promising strategy for improving therapy of the anterior segment eye diseases. However, further preclinical and clinical studies are required to confirm their clinical applicability.