Elsevier

Ophthalmology

Volume 120, Issue 4, April 2013, Pages 844-851
Ophthalmology

Original article
Clinical Classification of Age-related Macular Degeneration

https://doi.org/10.1016/j.ophtha.2012.10.036Get rights and content

Objective

To develop a clinical classification system for age-related macular degeneration (AMD).

Design

Evidence-based investigation, using a modified Delphi process.

Participants

Twenty-six AMD experts, 1 neuro-ophthalmologist, 2 committee chairmen, and 1 methodologist.

Methods

Each committee member completed an online assessment of statements summarizing current AMD classification criteria, indicating agreement or disagreement with each statement on a 9-step scale. The group met, reviewed the survey results, discussed the important components of a clinical classification system, and defined new data analyses needed to refine a classification system. After the meeting, additional data analyses from large studies were provided to the committee to provide risk estimates related to the presence of various AMD lesions.

Main Outcome Measures

Delphi review of the 9-item set of statements resulting from the meeting.

Results

Consensus was achieved in generating a basic clinical classification system based on fundus lesions assessed within 2 disc diameters of the fovea in persons older than 55 years. The committee agreed that a single term, age-related macular degeneration, should be used for the disease. Persons with no visible drusen or pigmentary abnormalities should be considered to have no signs of AMD. Persons with small drusen (<63 μm), also termed drupelets, should be considered to have normal aging changes with no clinically relevant increased risk of late AMD developing. Persons with medium drusen (≥63–<125 μm), but without pigmentary abnormalities thought to be related to AMD, should be considered to have early AMD. Persons with large drusen or with pigmentary abnormalities associated with at least medium drusen should be considered to have intermediate AMD. Persons with lesions associated with neovascular AMD or geographic atrophy should be considered to have late AMD. Five-year risks of progressing to late AMD are estimated to increase approximately 100 fold, ranging from a 0.5% 5-year risk for normal aging changes to a 50% risk for the highest intermediate AMD risk group.

Conclusions

The proposed basic clinical classification scale seems to be of value in predicting the risk of late AMD. Incorporating consistent nomenclature into the practice patterns of all eye care providers may improve communication and patient care.

Financial Disclosure(s)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Section snippets

Current Classification System Issues

The purpose of this report is to describe the modified Delphi process used to arrive at common terminology for a clinical classification system for AMD.11, 12 This process is intended as a consensus-establishing technique that combines the scientific literature with expert opinion.13, 14

Early stages of AMD usually are asymptomatic and have been characterized, across various classification systems, by the presence of drusen and pigmentary alterations within 2 disc diameters of the fovea.

Materials and Methods

The first steps in this process were to assemble a working group made up of 7 experts who were attending the January 2011 Arnold and Mabel Beckman Initiative for Macular Research conference to discuss how the process might move forward and to make specific recommendations regarding the next appropriate steps. These included a review of prior AMD classifications, a selection of additional experts in the field to establish a formal AMD classification committee, an agreement to use a modified

Results

In the original survey, a score of 7 through 9 indicating agreement for inclusion for a clinical staging system was achieved for 22 (28%) of 79 of statements, although consensus was noted in only 1 of these cases, with 21 being rated as equivocal and 0 rated as nonconsensus. Four statements were rated as inappropriate (median, 1–3) with consensus in 1 and equivocal in the 3 other statements. In the remaining 53 instances, agreement for inclusion was rated as uncertain (median, 4–6) with 9

Discussion

Using a modified Delphi technique, the committee developed a 5-stage AMD classification scale (Table 2). This approach has been used in many fields to attempt to establish consensus regarding important questions, including classification systems.16, 17, 18, 19 The process facilitates communication among a panel of experts regarding areas in which existing evidence-based information may be incomplete or unavailable. The focus of the technique is on the reliability of the expert group's opinion

Acknowledgment

The authors thank Dr. Ronald Klein, Madison, Wisconsin, and Dr. Johanna Seddon, Boston, Massachusetts, for their helpful review and advice for this manuscript.

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    Manuscript no. 2012-944.

    A list of all members of the Arnold and Mabel Beckman Initiative for Macular Research Classification Committee with affiliations can be found in Appendix 1.

    Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

    Supported by the Arnold and Mabel Beckman Initiative for Macular Research, Irvine, California.

    Group members listed after the references in Appendix 1.

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