TY - JOUR
T1 - Measuring geographic atrophy in advanced age-related macular degeneration
AU - Sunness, Janet S.
AU - Bressler, Neil M.
AU - Tian, Yan
AU - Alexander, Judith
AU - Applegate, Carol A.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1999
Y1 - 1999
N2 - Purpose. To present a method developed for measuring areas of geographic atrophy (GA) in advanced age-related macular degeneration. Methods. A microfilm reader projected the 30°fundus photograph of the macula. Retinal landmarks, atrophic areas, and spared areas within the atrophy were traced, without access to drawings of other years. The total atrophic area was calculated, as was the atrophy within a four-disc-area circle centered on the estimated foveal center. The configuration of the atrophy was documented. Results. Avoidable sources of discrepancy included variability in peripapillary atrophy seen on the photograph, and variability seen in the extent of the field. Reproducibility studies found a median absolute difference of 0.19 Macular Photocoagulation Study disc areas (DA) in total atrophy between repeat drawings, with 75% of repeat drawings having a difference of less than 0.33 DA. For central atrophy measures, there was a median difference of 0.08 DA, with 75% of pairs having a difference of less than 0.18 DA. Features making the definition of borders of GA difficult include the presence of drusen and pigmentary alteration, a fundus in which choroidal vessels are easily visible, and variation in the appearance of GA within a single area of atrophy. Conclusions. This method provides a reliable means of measuring the size of atrophic areas in GA and will be useful for measuring longitudinal change. It may be difficult to determine whether central spared areas are present, and correlation with visual acuity and macular perimetry may be helpful.
AB - Purpose. To present a method developed for measuring areas of geographic atrophy (GA) in advanced age-related macular degeneration. Methods. A microfilm reader projected the 30°fundus photograph of the macula. Retinal landmarks, atrophic areas, and spared areas within the atrophy were traced, without access to drawings of other years. The total atrophic area was calculated, as was the atrophy within a four-disc-area circle centered on the estimated foveal center. The configuration of the atrophy was documented. Results. Avoidable sources of discrepancy included variability in peripapillary atrophy seen on the photograph, and variability seen in the extent of the field. Reproducibility studies found a median absolute difference of 0.19 Macular Photocoagulation Study disc areas (DA) in total atrophy between repeat drawings, with 75% of repeat drawings having a difference of less than 0.33 DA. For central atrophy measures, there was a median difference of 0.08 DA, with 75% of pairs having a difference of less than 0.18 DA. Features making the definition of borders of GA difficult include the presence of drusen and pigmentary alteration, a fundus in which choroidal vessels are easily visible, and variation in the appearance of GA within a single area of atrophy. Conclusions. This method provides a reliable means of measuring the size of atrophic areas in GA and will be useful for measuring longitudinal change. It may be difficult to determine whether central spared areas are present, and correlation with visual acuity and macular perimetry may be helpful.
UR - http://www.scopus.com/inward/record.url?scp=0032990052&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032990052&partnerID=8YFLogxK
M3 - Article
C2 - 10393046
AN - SCOPUS:0032990052
SN - 0146-0404
VL - 40
SP - 1761
EP - 1769
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
IS - 8
ER -