Eyeworld

WINTER 2026 | EYEWORLD | 55 R Contact Fernández: joaquinfernandezoft@qvision.es Koch: dkoch@bcm.edu Relevant disclosures Fernández: None Koch: Johnson & Johnson Vision, Zeiss performance does the accumulated evidence actually show?" This evidence includes optical prediction, early clinical studies, independent peer-reviewed evidence, and later post-market data, while also considering the consistency and variability of those findings. "The ISO category tells the surgeon that a lens has met defined pre-market requirements, whereas the Function- al Classification describes the functional profile supported by the broader and evolving body of evidence," Dr. Fernández explained. "There does not need to be a one-to-one correspondence between the two because they are designed to answer different questions at different stages of the evidence pathway." "The power of this is it's actually based on clinical studies—it's how patients see," Dr. Koch said. "Why is that better than bench testing? Because it takes into account all the other fac- tors that are out in the real world—higher order aberrations of the cornea, pupil size, retinal performance." He added that more data are always welcome. "It will be incumbent upon us to not rely on one study to give a final word on an IOL." Under the Functional Classification, the same IOL could fall into different functional categories depending on which study produced the evidence. This, Dr. Fernández said, is not a limitation of the classification but reflects the fact that "a single study is influenced by meth- odological choices, measurement variability, and the characteristics of the population being eval- uated. … In this context, the relevant endpoints may include the increase of the DOFi and the difference in visual acuity between intermediate and near distances. Because these endpoints may vary across studies as a consequence of testing methodology, sample characteristics, and individual biometric factors, the functional cate- gory assigned to a particular IOL may also vary. Clinicians should therefore avoid interpreting the category derived from a single study as an absolute property of the lens. Instead, classifi- cation should be considered in the context of the overall body of evidence, with increasing confidence as results become consistent across multiple independent studies and populations." What's next? The Working Group is continuing to refine the Functional Classification, which is based on monocular distance-corrected visual acuity defocus curves. This refinement could include incorporating patient-reported outcome mea- sures, contrast sensitivity, dysphotopsias, and more. Dr. Fernández said these variables would need to have enough standardized evidence and evidence between groups that is clinically meaningful. He said he would prioritize out- comes that directly reflect functional vision and the patient experience. The current functional classification, he added, although based on monocular defocus curves, can identify clini- cally meaningful differences in binocular visual acuity and spectacle independence. Dr. Fernández also said it's important that functional outcomes be distinguished from variables that could modify these outcomes, such as pupillometry and corneal aberrations, which could modify an IOL's performance. "This distinction is reflected in the Functional Vision Working Group's PECO framework: Predict- ability, Exploratory evidence, Confirmatory evidence, and Optimization. In this framework, optimization specifically considers the indepen- dent variables that may influence functional outcomes. Therefore, future IOL evaluation should evolve progressively incorporating new endpoints only when both sufficient evidence and clinical relevance are demonstrated, while using patient-specific factors to better under- stand and optimize functional performance." Dr. Fernández said he hopes this consensus on IOL classification will encourage research- ers and industry to align endpoints for a study closely with the specific objective. "When the aim is to characterize the intrinsic functional performance of an IOL and determine its func- tional category, monocular distance-corrected defocus curves should be prioritized," he said, adding that "monocular distance-corrected testing helps reduce the influence of binocular summation, residual refractive error, and other factors that may confound the assessment of the lens itself. "At the same time, the consensus should also reinforce the idea that functional classifi- cation and real-world functional performance are not the same thing," Dr. Fernández contin- ued. "Once a lens has been characterized and classified, binocular and uncorrected outcomes become extremely important because they better reflect how the patient actually experi- ences vision in daily life. Therefore, binocular continued on page 56

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