Functionalized hydrogels in ophthalmic applications: Ocular inflammation, corneal injuries, vitreous substitutes and intravitreal injection

With the prevalence of eye diseases, such as inflamed eyes, corneal injury, cataract, glaucoma, and retinal degenerative diseases, different clinical strategies have been developed, however, they still suffer from many inevitable drawbacks in practical applications. Functionalized hydrogels have emerged as attrac-tive materials and revolutionary strategies for ophthalmic applications owing to their favorable proper-ties, such as excellent biocompatibility, near-physiological extracellular matrix environment, injectability, tailorable structure, inherent flexibility, dynamically adjustable mechanical properties, par-ticularly attractive self-adhesion, enviable cell delivery, and sustained drug release capabilities. In this review, various functionalized hydrogels for different ophthalmic diseases have been comprehensively summarized. The review also systematically introduces the advanced research progress in ophthalmic applications, including topical administration for superficial inflamed eyes, dressings for corneal injuries, injectable drug delivery system for glaucomatous optic neuropathy, vitreous substitutes after vitrectomy, intravitreal administration for intraocular diseases, and etc. Finally, the scientific challenges and untapped potential are expounded to demonstrate the future prospects of engineered hydrogels for the treatment of ocular diseases. The review aims to provide comparative perspectives and multifaceted insights to inspire more in-depth research on hydrogels and provide guidance for their varied applica-tions in ophthalmology.(c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).