Medical and technical aspects of using intraocular lenses with extended depth of field

Purpose: to analyse the medical and technical aspects of intraocular lenses (IOLs) with extended depth of field (EDOF). Literature analysis was performed in the PubMed international database, the search keywords being “IOL with extended depth of field” (EDOF), “Optical Bench Evaluation of IOL”, “Preclinical evaluation of IOL”, “Aberrations”, “Monofocal IOL” (MOFIOL), “Multifocal IOLs” (MUFIOL). A total of 226 sources were analyzed, further using systematic review filters and the authors' knowledge of the topic. The duration of the retrospective analysis was 7 years (2016–2022), some of the considered work dates back to 2023. Unlike MUFIOL, EDOF lenses create a single elongated focal point to increase the depth of field, rather than several foci. Thus, EDOFs are aimed at reducing light phenomena, glare and halos, the occurrence of which is characteristic of MUFIOL. A potential disadvantage of EDOF is the reduction in retinal image quality with an excessive increase in the number of aberrations. The factors of the medical and technical assessment of the IOL indicate a high correlation with the predicted visual acuity (VA). EDOFs, whose design features are based on a higher order aspherical design, provide comparable optical quality for the far and extended intermediate ranges, while producing halo effects comparable to those of MOFIOL. Designed to improve depth of field with a full correction of corneal spherical aberration, EDOF provides intermediate-level pupil-independent improvement in VA and maintains visual acuity unlike conventional MOFIOLs. The quality of visual perception and the predicted VA of various types of EDOFs depend on the optical technology and the correction of corneal spherical aberrations. EDOFs can be expected to provide adequate vision at an intermediate distance (with a possibility of insufficient near vision). At the same time, the expansion of the depth of field varies between models, which should be taken into account when preoperatively choosing EDOF for a specific type of daily visual activity of the patient, especially for people with visually strenuous work. The results of the medical and technical assessment are widely used in the clinical testing of specific types of EDOF IOLs.