Fig. 13

Digital single-lens reflex (DSLR) camera test (Near distance). With the monofocal lens, as the distance from the Early Treatment Diabetic Retinopathy Study (ETDRS) chart decreases, the images become increasingly blurry. With a multifocal lens, as the distance from the ETDRS chart decreases, they become very clear at a certain position. At this position, the distance between the pupil and ETDRS chart was approximately 500 mm. As the distance becomes smaller, it becomes blurry again. A Monofocal lens (the distance between the achromatic converging lens surface and the DSLR camera sensor: 660 mm); B Monofocal lens (distance: 500 mm); C Multifocal lens (distance: 660 mm); D Multifocal lens (distance: 500 mm)