The critical gap between clinically required durability and metabolic functionality in corneal prostheses drives the need for biomaterials that recapitulate the structural hierarchy of cornea. To address this, we introduce a solvent-free water vapor-induced phase separation (wVIPS) strategy, enabling the self-assembly of dodecenyl-modified agarose (DAA) into hydrogels that recapitulate the structural hierarchy of native cornea. The DAA hydrogel exhibits a microporous architecture with pore sizes analogous to the corneal stroma, facilitating essential mass transport while maintaining ultraviolet (UV)-protective transparency (> 90% visible light transmittance). Unlike brittle and chemically crosslinked agarose hydrogels, the DAA hydrogel achieves tissue-like mechanical properties, including high tensile strength of 1.66 MPa and suture retention strength of 1.57 N, due to the synergistic effects of hydrophobic microdomains and hydrogen bonding between DAA chains. In addition, the wVIPS process eliminates toxic crosslinkers, ensuring 180 days stability in artificial tears and excellent biocompatibility. Consequently, the DAA hydrogel demonstrated seamless host integration without scarring and promoted restoration of corneal barrier function in a rabbit lamellar keratoplasty model. By establishing microphase separation as a universal design strategy, this work advances polysaccharide-based biomaterials for load-bearing ophthalmological applications, effectively bridging nanoscale self-assembly with macroscale tissue functionality.