Whether to have monofocal or bifocal for cataract in the elderly can be decided according to one’s choice. Monofocal can only focus on a particular distance, bifocal has continuous clear vision at distance, intermediate and near distances, and the comfort level is better than monofocal. 1. Monofocal: Monofocal lens can neutralize the corneal spherical aberration to a certain extent and reduce the spherical aberration of the postoperative eye, but it can only focus on a specific distance, i.e., only one of the distances, i.e., distance, intermediate distance and near distance can be seen the most clearly, and the rest of the distances will be presented with blurred images. 2. Multifocal: Bifocal lens is closer to the optical principle of continuous zoom of the lens in the human eye, after implantation, it can show clear image no matter far, middle and near distance, which can make patients see clearly and comfortably, but whether or not it can be implanted needs a series of comprehensive assessment of the eye to decide. Whether an elderly cataract should be monofocal or bifocal, the final choice of IOL can be made based on a comprehensive evaluation of the preoperative examination.