New grading criteria allow for earlier detection of geographic atrophy in clinical trials.
OBJECTIVE
To evaluate new grading criteria for geographic atrophy (GA), as detected by annual stereoscopic color fundus photographs and fluorescein angiograms, and to assess whether application of the revised criteria provides earlier identification of GA than previous criteria involving only color fundus photography.


METHODS
Annual fundus image sets from 114 CAPT patients who developed GA in the untreated eye during 5 to 6 years of follow-up were reassessed for the presence of GA, using revised grading criteria, in which GA was defined by (1) the presence of hyperfluorescence on fluorescein angiography; and (2) at least one other characteristic indicative of involution of the retinal pigment epithelium (i.e., sharp edges, excavation of the retina, or visible choroidal vessels on either color images or fluorescein angiograms). Reliability and time of initial detection of GA using the revised criteria were assessed.


RESULTS
The revised criteria are reliable (97.8% intragrader, 93.3% intergrader agreement) and accurate (false-positive rate, 0.8%) for detecting individual early GA lesions. Using this revised method, individual GA lesions were identified 1-year earlier on average than was possible with criteria used in previous CFP studies. The use of two imaging modalities was more sensitive in detecting GA and its features than either imaging modality alone (P ≤ 0.0001).


CONCLUSIONS
Early GA areas can be reliably identified when defining criteria are based on both color photographs and fluorescein angiograms. These methods can be used to investigate the natural history of GA earlier in the course of disease than previously possible and to facilitate the design of future clinical trials of treatments for GA. (ClinicalTrials.gov number, NCT00000167).
Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-3309, USA. hilary.brader@uphs.upenn.edu
Hilary Smolen
HS
Brader
Gui-Shuang
GS
Ying
E Revell
ER
Martin
Maureen G
MG
Maguire
D005189:False Positive Reactions; D005451:Fluorescein Angiography / Q000145:classification*; D005500:Follow-Up Studies; D057092:Geographic Atrophy / Q000175:diagnosis* / Q000503:physiopathology / Q000517:prevention & control; D006801:Humans; D017075:Laser Coagulation; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013997:Time Factors; D014786:Vision Disorders / Q000517:prevention & control; D014792:Visual Acuity / Q000502:physiology