Four-point scale for AMD risk

A presentation given at Hawaiian Eye 2007 meeting in January, outlined a four-point scale that may help to simplify the assessment of a patient's risk of developing age-related macular degeneration (AMD).

Frederick L. Ferris III, MD described how the scale was developed from the Age-Related Eye Disease Study (AREDS) clinical severity scale for AMD. This began life as a complex nine-step, five-year progression scale but, by focusing on simple clinical features, it was reduced to a five step, four-point model.

It focuses on large drusen (defined as drusen greater than 125 µm in diameter) and pigmentary changes. The old scale required grading of hyperpigmentation whereas the new scale just needs to know whether there is a pigmentation change or not.

Each eye is evaluated separately, with these factors in mind, and the scores combined. If large drusen are present, one point is counted and one point is also counted where there is a pigmentary change. There is a possible score of four points when the totals for each eye are combined.

Patients with a combined score of four points have a 50% risk of developing advanced AMD over five years, those with a score of three points have a 25% chance, those with a score of two have a 12% chance and those with a score of one have a 0.5% chance.

Dr Ferris suggested that this new scoring method could be used in future clinical trials as a tool for assessing eligibility.