Global consensus on the evidence-based functional classification of simultaneous vision IOLs

In a landscape defined by the rapid and sustained proliferation of intraocular lens (IOL) models after the first IOL introduced by Sir Harold Ridley in 1949, alongside a growing volume of clinical studies providing evidence of their functional benefits, the need for a unified, comprehensive, and internationally standardized Functional Vision Framework for both Functional Classification and the consistent measurement and reporting of clinical outcomes has become a matter of great importance.1 The European Society of Cataract and Refractive Surgeons (ESCRS), the American Society of Cataract and Refractive Surgery (ASCRS), the Asia-Pacific Association of Cataract and Refractive Surgeons (APACRS), and the Latin American Society of Cataract and Refractive Surgery (LATAMSCRS) have collectively propelled the evolution of the Functional Vision Framework, advancing them beyond the limitations of purely optical design. Their work emphasizes clinically meaningful outcomes that more accurately reflect patients' daily visual performance and overall quality of life. The ESCRS proposal for a Functional Classification based on the range of the depth of field (ROF), the ASCRS recommendations to use the term “depth of field” with the abbreviation DOFi in lieu of “range of the depth of field” with the abbreviation ROF, and to adopt the Assessment of IntraOcular Implant Symptoms (AIOLIS) questionnaire, a tool developed by the American Academy of Ophthalmology (AAO) to enhance consistency in postoperative symptom assessment, and APACRS and LATAMSCRS's emphasis on the role of optical bench data during early stages of evaluation were all highlighted during the Functional Vision Working Group (FVWG) meeting at the 43rd Congress of the ESCRS in Copenhagen, Denmark, in September 2025.2,3 Recognizing the overlap in objectives and the need for harmonization, ESCRS, ASCRS, APACRS, and LATAMSCRS established the Global Functional Vision Working Group (FVWG). Its goal is to set a global standard for evidence-based knowledge generation in IOL research and clinical practice. Functional Classification Terminology and Aims The Functional Classification of IOLs is based on the ROF and the enhancement of visual acuity from intermediate to near distances. However, based on commentary by Riaz et al., the FVWG agreed that the abbreviation ROF could be confused with peripheral visual field terminology.4 As a result, we recommend using depth of field (DOFi) exclusively because it promotes clearer and more consistent communication among clinicians and researchers (Figure 1).Figure 1.: Updated diagram of Functional Classification depending on (1) the DOFi achieved in the monocular defocus curve with best correction at distance at 0.2 logMAR VA level and (2) the improvement of VA from intermediate to near (ΔVA).2 DOFi = depth of fieldAlthough the number of categories and cutoffs derived from a synthesis of current evidence remains at 6, the FVWG agreed to rename them as follows: Partial-DOFi Narrowed, Enhanced, and Extended; and Full-DOFi Steep, Smooth, and Continuous. Members also agreed to order the subcategories according to the functional benefits they provide to patients. Although 1.1.—Narrowed, 1.2.—Enhanced, and 1.3.—Extended reflect a progressive increase in DOFi accompanied by a gradual compromise in far distance visual quality, the 2.1.—Steep, 2.2.—Smooth, and 2.3.—Continuous categories represent a progressive enhancement in intermediate visual performance, which may be associated with a corresponding progressive reduction in near visual quality (Table 1; Figure 2).2,5 Table 1. - Functional classification of IOLs by depth and shape of defocus curves (normalized to 0 logMAR at best distance correction) DOFi for 0.2 logMAR (Diopters, D) DOFi for 0.3 logMAR (Diopters, D) ΔVA (logMAR) 1. PARTIAL-DOFi