This review aims to examine existing research on the development of ocular drug delivery devices utilizing hyaluronic acid (HA). Renowned for its exceptional biocompatibility, viscoelastic properties, and ability to enhance drug bioavailability, HA is a naturally occurring biopolymer. The review discussed specific mechanisms by which HA enhances drug delivery, including prolonging drug residence time on ocular surfaces, facilitating controlled drug release, and improving drug penetration through ocular tissues. By focusing on these unique functionalities, this review highlights the potential of HA-based systems to revolutionize ocular treatment. Various fabrication techniques for HA-based ocular drug delivery systems, including hydrogels, nanoparticles, and microneedles, are discussed, highlighting their respective advantages and limitations. Additionally, this review explores the clinical applications of HA-based devices in treating a range of ocular diseases, such as dry eye syndrome, glaucoma, retinal disorders, and ocular infections. By comparing the efficacy and safety profiles of these devices with traditional ocular drug delivery methods, this review aims to provide a comprehensive understanding of the potential benefits and challenges associated with HA-based systems. Moreover, this review discusses current limitations and future directions in the field, such as the need for standardized fabrication protocols, long-term biocompatibility studies, and large-scale clinical trials. The insights and advancements presented in this review aim to guide future research and development efforts, ultimately enhancing the effectiveness of ocular drug delivery and improving patient outcomes.

Corneal endothelial dysfunction is a leading cause of vision impairment globally, traditionally managed through donor-dependent keratoplasty procedures. However, limitations in donor tissue availability, surgical complexity, and long-term graft survival have prompted the development of cell-based regenerative therapies. Among these, corneal endothelial cells (CECs) injection therapy has emerged as a minimally invasive alternative, offering the potential to restore endothelial function. This review provides a comprehensive analysis of recent advances in bioengineering strategies for CECs therapy, including cell sourcing from donor tissue, pluripotent stem cells, and transdifferentiated somatic cells; optimization of culture conditions and substrates; and delivery protocols that enhance cell adhesion and survival. We further examine clinical trial outcomes and propose future directions for clinical translation. The convergence of cell biology, biomaterials engineering, and translational medicine positions CECs injection therapy as a transformative solution to corneal blindness.

Ocular surface inflammation is a major disruptor of corneal epithelial homeostasis and a key driver of limbal stem cell deficiency (LSCD). Limbal stem cells (LSCs), residing within the specialized limbal niche, maintain corneal transparency through continuous epithelial renewal and by preventing conjunctival encroachment onto the corneal surface. Chronic or severe inflammatory insults—stemming from systemic autoimmune disorders, ocular surface diseases, infections, trauma, or environmental stressors—can damage both LSCs and their microenvironment, ultimately leading to limbal insufficiency. This review synthesizes current insights into the mechanisms by which inflammation impairs LSC survival, including cytokine-mediated cytotoxicity, oxidative stress, immune cell infiltration, and disruption of essential signaling pathways such as Wnt, Notch, and BMP. The distinction between LSC depletion and LSC dysfunction is highlighted, as residual stem cells may persist even in clinically advanced disease and can regenerate the corneal surface once the inflammatory milieu is corrected. Clinical manifestations, staging systems, and diagnostic markers—including p63α, ABCG2, and additional emerging molecular indicators—are summarized to support accurate assessment of LSCD severity. Current therapeutic strategies, ranging from anti-inflammatory medical management to surgical approaches such as SLET, CLET, and allogeneic transplantation, are reviewed alongside evolving regenerative and cell-based therapies. By integrating mechanistic understanding with clinical implications, this review underscores the critical interplay between inflammation and limbal niche failure and emphasizes the importance of early recognition and targeted intervention to preserve or restore LSC function.

Corneal endothelial dysfunction is a major cause of corneal blindness worldwide. This is primarily due to the limited regenerative capacity of human corneal endothelial cells (CECs) and the global shortage of donor tissues. Corneal endothelial cell therapy (CECT), which involves injecting cultured CECs into the anterior chamber, has emerged as a promising alternative to conventional transplantation. However, its clinical efficacy remains limited by several factors, including rapid cell loss, non-uniform distribution, and insufficient long-term adhesion following injection. Recent advances in biomaterials and regenerative engineering have led to the development of emerging biomaterial-assisted strategies aimed at addressing these challenges. In this review, we provide a mechanistic and translational overview of next-generation CECT, highlighting a range of biomaterial-assisted strategies aimed at improving cell retention, spatial localization, and long-term adhesion following injection. These emerging approaches aim to mitigate key limitations of conventional cell injection therapy, including variability in cell distribution and retention. However, their effectiveness and translational feasibility remain under active investigation. In addition, we analyze recent global patent trends, regulatory frameworks, and market dynamics to highlight emerging opportunities for innovation and development in this field. Although many of these technologies remain at the preclinical or early translational stage, these approaches may provide a promising direction to improve engraftment efficiency, reduce surgical variability, and enable more scalable, minimally invasive treatment options. This review highlights the potential of biomaterial-assisted CECT as a next-generation regenerative strategy and outlines key challenges that must be overcome for successful clinical translation.

The unique anatomy and physiological barriers of the human eye—particularly rapid tear turnover and limited corneal permeability—present significant obstacles to achieving effective topical drug delivery. In response to these constraints, biopolymer-based extended-release systems have emerged as a promising and transformative class of ocular therapeutics. This review provides a comprehensive overview of recent advances in natural biopolymers, including polysaccharides and protein-derived polymers, for application on the ocular surface. These materials exhibit advantageous characteristics such as mucoadhesion, biocompatibility, and stimuli-responsive behavior, which collectively enhance precorneal residence time and enable controlled, sustained drug release. We further discuss diverse delivery platforms—ranging from in situ forming hydrogels and mucoadhesive nanoparticles to drug-eluting contact lenses and microneedle-based systems. In addition, we highlight how the integration of nanotechnology and bioinspired scaffolds can augment the delivery efficiency of therapeutic agents to ocular tissues. Overall, this review underscores the ongoing transition from conventional topical eye drops to sophisticated, functionalized delivery systems capable of maintaining therapeutic drug levels while simultaneously supporting tissue repair and wound healing. Finally, we outline the remaining challenges in clinical translation and consider the future potential of smart, responsive biopolymer systems in advancing the treatment of both anterior and posterior segment diseases.