The instruments for corneal power measurements include keratometer, IOL-Master,  corneal topography, and so on. The principles of the measurement of these instruments include  simulated keratometry(SimK), total corneal power based Gaussian optic formula(KGOF) and total corneal power obtained by ray tracing method(Kray). The correlation between the anterior and posterior corneal surface is limited. If we ignore the posterior corneal power, cataract surgery with Toric intraocular lens implantation will cause with-the-rule astigmatism overcorrection or against-the-rule astigmatism undercorrection. Therefore, it is essential to measure individual posterior corneal power and obtain accurate total corneal power for the recovery of visual acuity after  refractive cataract surgery. (Int Rev Ophthalmol,  2017,  41:   414-418)