CRYAA encodes alpha A-crystallin, a structural protein essential for lens transparency and refractive index 1. Beyond its lens role, CRYAA functions as a molecular chaperone in its oxidized form, preventing protein aggregation under stress conditions and maintaining cellular protein homeostasis 2. The protein is required for proper formation of lens intermediate filaments in complex with BFSP1 and BFSP2 3. Mutations in CRYAA cause autosomal dominant congenital cataracts with variable clinical presentation. The R12L mutation increases protein aggregation and aggresome formation, leading to lens opacification and microphthalmia 4. The E156K mutation induces epithelial-mesenchymal transition in lens epithelial cells via Wnt/β-catenin and FAK/Src signaling, increasing cellular migration 5. Meta-analysis shows the rs7278468 polymorphism is associated with significantly decreased cataract risk 6. Beyond ocular tissues, CRYAA protects retinal pigment epithelium from oxidative stress and apoptosis by activating the SIRT1-PI3K/AKT signaling pathway through suppression of miR-155-5p 2. During development, high CRYAA expression in retina promotes visual acuity recovery after sensory deprivation 7. These findings establish CRYAA as critical for both lens homeostasis and retinal neuroprotection.