ASCRS 2026: Daniel H. Chang, MD, outlines paradigm for characterizing depth-of-field IOLs

Daniel H. Chang, MD, presented the ASCRS Functional Vision Working Group’s proposed framework for characterizing presbyopia-correcting intraocular lenses, outlining a more disciplined and clinically practical approach to defining what the group terms depth of field IOLs. His presentation at the 2026 American Society of Cataract and Refractive Surgery (ASCRS) annual meeting focused on standardizing nomenclature and introducing a functional vision model built around three core domains—“visual quality, visual range, visual symptoms”—to support lens selection, patient counseling, and postoperative management.

A central focus of the presentation was terminology. Chang noted that these lenses have historically been described by a wide range of overlapping labels, including “simultaneous vision lenses” and “multifocal lenses,” creating inconsistency in both clinical discussion and patient communication. The working group’s proposal is to anchor terminology to the functional quantity being described: depth of field.

Chang framed the discussion around practical surgical decision-making, beginning with the question, “How do surgeons talk with patients?” He emphasized that the purpose of the framework is to help surgeons select the most appropriate lens for individual visual needs and to better troubleshoot postoperative concerns. Unlike monofocal lenses, which are intended primarily to improve vision and reduce refractive error, depth-of-field lenses are designed to expand visual range, with the acknowledged trade-off that “that’s gonna compromise visual quality.”

The proposed model defines visual quality as contrast sensitivity across a range of spatial frequencies, visual range as contrast sensitivity along the visual axis at far, intermediate, and near distances, and visual symptoms as contrast sensitivity across the visual field, particularly under challenging lighting conditions. Together, “visual quality, visual range, visual symptoms” are intended to provide a concise framework for describing functional vision in real-world space.

Trade-offs remain central to the framework. As Chang said, “if you get more of one, you get less of the other, and there’s, there’s always a trade-off.” This structure is intended to help surgeons systematically balance sharpness, range of focus, and dysphotopsias—including glare, halo, and starbursts—according to patient priorities.

Chang also emphasized the value of clinical outcomes over purely benchtop metrics, citing published literature, defocus curve analyses, and aggregated study data as the basis for clinically meaningful lens categories. The broader goal is to move beyond anecdotal impressions toward a structured approach that clarifies lens strengths and weaknesses, improves preoperative counseling, and informs future IOL development.