Corneal visualization Scheimpflug technology(Corvis ST)is currently the most commonly used clinical device for assessing in vivo corneal biomechanics. The new parameter stress-strain index(SSI)has been a hot topic of clinical research in recent years, which not only directly reflect corneal biomaterial stiffness, but also closely correlates with the progression of certain diseases. SSI was generated based on the predictions of corneal behavior using finite element(FE)numerical modeling to simulate the effects of intraocular pressure and Corvis ST jets. The SSI algorithm does not change with central corneal thickness(CCT), intraocular pressure, or biomechanically corrected intraocular pressure(BIOP), but it is clearly associated with altered collagen fibres in the corneosclera. The principles of SSI, the relationship between age and SSI, the relationship between axial length and SSI, the relationship between myopia and SSI, and the application of SSI are summarized and concluded.