Clinical classification of age-related macular degeneration

Abstract

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.

Figure 1.

In an eye with multiple drusen variants, the Age-Related Eye Disease Study drusen grading circles C0 (63-μm diameter) and C1 (125-μm diameter) are superimposed for size comparison. Small drusen are smaller than the C0 circle (drupelets). Lesions larger than C0 but less than C1 are considered medium drusen, and lesions larger than C1 are large drusen. Within the inset, drupelets and medium drusen are seen. Faint reticular drusen also may be seen in the superior macular region.

Figure 2.

The largest druse in this eye is slightly larger than the C1 (125 μm) circle and is classified as a large druse. Adjacent intermediate-sized drusen can be seen.

Figure 3.

Graph showing age-related eye disease clinical severity scale for age-related macular degeneration (AMD), demonstrating the 5-year risk of developing advanced AMD for various risk groups. AREDS = Age-Related Eye Disease Study.

Figure 4.

Graph showing the 10-year risk of developing advanced age-related macular degeneration (AMD) in eyes without large drusen at baseline for various risk groups.

Figure 5.

Graph showing the 10-year risk of developing large drusen in eyes without large drusen at baseline for various risk groups.

Figure 6.

Graph showing the 10-year risk of developing advanced age-related macular degeneration (AMD) in an eye with a fellow eye with late AMD for various risk groups.