This invention describes strategies and devices for improving the visual experience while expanding the depth of field of presbyopic and pseudophakic patients. The invention describes strategies and devices for providing improved image quality and improved visual quality of patients employing simultaneous vision bifocal, trifocal or multifocal corrections or monovision. The invention describes strategies and devices for reducing the visibility of the defocused part of the retinal image generated by simultaneous vision bifocal and multifocal ophthalmic corrections and monovision. The invention describes strategies and devices that employ control of spherical aberration or other similar asphericities to reduce the visibility of defocused ghost images. The invention describes strategies and devices that ensure that negative defocus is always coupled with negative spherical aberration (or similar asphericity), and that positive defocus is always coupled with positive SA (or similar asphericity) as a means to reduce the visibility of defocused ghostimages.
