THROUGH FOCUS IMAGE QUALITY OF EYES IMPLANTED WITH MONOFOCAL AND MULTIFOCAL INTRAOCULAR LENSES

A double-pass method is applied to determine the retinal image quality of eyes implanted with intraocular lenses (IOLs). The effect of focus on image quality was measured in two groups of patients that had been implanted with either monofocal or multifocal IOLs. The results show that the overall retinal image quality is reduced in eyes with multifocal lenses with respect to that implanted with monofocal IOLs. Although the depth of focus is larger in multifocal IOLs (4 to 5 D) than in the monofocal IOLs (2 to 3 D), some patients implanted with monofocal IOLs have higher image quality than those implanted with multifocal IOLs in a range of about 4 D around the best focus. In eyes implanted with monofocal IOLs, astigmatism plays a major role to reduce the retinal contrast, but also increases the depth of focus. These ''in vivo'' measurements show that there is considerable variability in image quality among individuals with the same type of monofocal IOLs. The main factors causing this variability seem to be age and astigmatism produced by surgery.