The main difference between an IOL eye and a normal eye is the different composition of the refractive interstitium inside the eye. The refractive interstitium of a normal eye consists of the cornea, the aqueous humor, the lens, and the vitreous humor, of which the lens is about 4 millimeters thick. The lens in the refractive interstitium of an IOL eye is replaced by an artificial crystal, and the other components are the same. The thickness of the IOL is relatively thin, usually around 0.5 millimeters. If the IOL implanted inside the eye is an ordinary IOL, it generally does not have the function of adjustment, and at this time the patient is equivalent to being in a presbyopic state compared with normal people; if the IOL implanted is an adjustable IOL or a multifocal IOL, the patient’s degree of clarity in seeing far and near is basically the same as that of a normal eye.