The multifocal IOL has two optimal focal points – one at infinity and the other at approximately 31mm. As the object moves closer from infinity to about 70mm, the visual acuity slowly decreases from 1.0 (20/20) to 0.5 (20/40); as the object continues to move closer to 30mm, the visual acuity gradually improves again to 0.8-1.0 (20/25-20/20). In contrast, monofocal IOLs have only one optimal focus at infinity, and visual acuity decreases progressively as the object is gradually moved closer. When the object is 70 mm away from the eye the visual acuity is still good, while when the object is moved closer to 50 mm the visual acuity decreases to 0.3 (20/60). It has been established in all published articles that multifocal IOLs provide good near visual acuity and high patient satisfaction, and no statistical difference was found between the multifocal and monofocal lens groups in terms of bare eye distance visual acuity. The differences in equivalent spherical lenses between the two groups of patients may be due to subtle differences in the design of the different IOLs that did not achieve the desired postoperative refractive state. Patients with multifocal IOLs were set to a slight hyperopic or orthophoric state for optimal postoperative visual acuity, while patients with single-intersection IOLs were set to a slight myopic or orthophoric state. The percentage of patients with bare eye distance visual acuity or best corrected distance visual acuity better than 1.0 (20/20) was not statistically different between the two groups, while another study comparing diffractive multifocal IOLs and monofocal IOLs showed that the monofocal group was able to have more patients with best corrected distance visual acuity of 1.0 (20/20) or better and was statistically significant, and as expected, the multifocal group had better corrected and uncorrected near visual acuity. Studies of different diffractive multifocal IOLs showed that 86.8 to 87.9 percent of eyes had bare eye near vision of 0.5 (20/40) or better. However, patients in the multifocal group were not as satisfied with their naked intermediate visual acuity as they were with their naked near and distance visual acuity, and some patients occasionally required glasses to obtain better intermediate visual acuity, and questionnaires showed no realistic advantage in intermediate visual acuity in the multifocal group compared to the monofocal group. However, some studies have reported that the vision obtained with multifocal IOL implantation is not an “all or nothing” phenomenon, i.e., the patient can see only infinitely far or very close objects, but also has very useful intermediate distance vision, i.e., full vision, and this overall improvement in vision is what is called “proposed adjustment”.