Abstract: The pathogenesis of age-related cataracts remains unclear. Oxidative stress is considered associated with the occurrence of age-related cataract at present. Telomere length is the “molecular clock” for cell lifespan. Telomere shortening is associated with senescence of cells, and oxidative stress can accelerate telomeric damage and telomere shortening. Telomerase can maintain telomere length, increase the resistance to oxidative stress, and promote cell proliferation. Telomerase activity only exists in several somatic cell types, including lens epithelium. In lens epithelial cells, telomerase mainly improves cells’ resistance to oxidative stress, and protect cells from damage, rather than promote cell proliferation. Varying from animals and humans, the association between telomere length and cataract is species-specific. Therefore, an insight into the interaction of oxidative stress with the telomeric system and their influence on the pathogenesis of age-related cataracts is helpful for the treatment and prevention of age-related cataracts.(Int Rev Ophthalmol, 2020, 44：99-104)