As has been emphasized in this publication many times, language matters. Several articles have argued for revising terminology through the application of both consensus and common sense.
It is therefore disappointing that the International Organization for Standardization (ISO), in its release of the standard 11979-7 Part 7,1 has classified IOLs according to the following categories: (A) monofocal; (B) toric; (C) simultaneous vision lenses, which are subdivided into multifocal, extended depth of focus, and full visual range; and (D) accommodating. Several issues arise from this classification system, including a lack of consistency, the use of the term focus in one category (extended depth of focus) and vision in another (full visual range).
The term simultaneous vision lenses is particularly confusing. It is not easily understood by ophthalmologists or patients, who are the ultimate recipients and beneficiaries of high-performance IOLs (not presbyopia-correcting IOLs, because they do not correct the condition of presbyopia).
To further complicate matters, the Journal of Cataract & Refractive Surgery recently published an article, supported by the ESCRS, proposing an “evidence-based functional classification of simultaneous vision intraocular lenses,”2 which only deepens the confusion introduced by the ISO.
Effective nomenclature is (1) simple, (2) consistent, (3) understandable to all stakeholders, and (4) flexible enough to accommodate future changes. According to the foreword of the document, the ISO’s work was carried out by “technical committees,” though their composition is unclear. This raises questions. First, which, if any, ophthalmologists were involved? More importantly, did laypeople participate—a practice we are increasingly encouraged to consider when developing any sort of policy or framework in the modern age?
In 2020, AECOS, responding to the confusion around IOL terminology among ophthalmic colleagues, organized a working group on IOL nomenclature. The process involved collaboration with manufacturers, colleagues, and patients to create terminology that adhered to clear principles. In summary, lenses were classified based on three criteria: (1) function (range of focus), subdivided into monofocal, monofocal plus, increased range of focus, and full range of focus; (2) mechanism of action; and (3) dysphotopsias. The nomenclature was presented at AECOS Europe meetings on two occasions3,4 and featured in two articles in Cataract & Refractive Surgery Today Global | Europe Edition5,6 and one piece in The Ophthalmologist.7 There has been significant enthusiasm in Europe for the AECOS nomenclature because it is easily understood by all parties involved, especially patients.
Manufacturers may feel compelled to adopt ISO terminology when labeling their products. Colleagues should exercise caution and, when using non-ISO terminology in their communication—whether written, electronic, or oral—must avoid specifying lens models. Doing so could lead to accusations of providing false or misleading information and labeling.
It is a privilege to be in this profession and to care for patients. As we all know, clear communication is vital. The language we use must be easy for patients to understand to ensure that their expectations are met. Let’s keep it simple.
Sheraz M. Daya, MD, FACP, FACS, FRCS(Ed), FRCOphth | Chief Medical Editor
1. ISO 11979-7:2024. Ophthalmic implants—intraocular lenses—part 7: clinical investigations of intraocular lenses for the correction of aphakia. 5th ed. International Organization for Standardization; 2024. Accessed September 16, 2024. https://www.iso.org/standard/79689.html
2. Ribeiro F, Dick HB, Kohnen T, et al. Evidence-based functional classification of simultaneous vision intraocular lenses: seeking a global consensus by the ESCRS Functional Vision Working Group. J Cataract Refract Surg. 2024;50(8):794-798.
3. Daya S. Lenspeak—an AECOS Europe initiative. Presented at: AECOS Europe; June 10, 2022; Antwerp, Belgium.
4. Daya S. Presented at: AECOS online symposium 2021.
5. Daya SM. Let’s speak lenspeak. Cataract & Refractive Surgery Today Europe. February 2021. Accessed September 16, 2024. https://crstodayeurope.com/articles/feb-2021/lets-speak-lenspeak/?single=true
6. Ambati B, Daya SM, Trinh T. Standardizing terms in cataract and refractive surgery. Cataract & Refractive Surgery Today Global | Europe Edition. March/April 2023. Accessed September 16, 2024. https://crstodayeurope.com/articles/mar-apr-2023/standardizing-terms-in-cataract-and-refractive-surgery/?single=true
7. Daya S. Clear-cut classification. The Ophthalmologist. March 5, 2022. Accessed September 16, 2024. https://theophthalmologist.com/subspecialties/clear-cut-classification
