Purpose
We aimed to determine the association between abnormal fundus autofluorescence (FAF) features on images obtained from a modified fundus camera (mFC) (Topcon, Paramus, New Jersey, USA) and the progression of geographic atrophy (GA) in patients with age-related macular degeneration (AMD).
Methods
Consecutive serial FAF images of 103 eyes from 103 patients with GA were enrolled. All FAF images were obtained with an mFC (excitation, approximately 500-610 nm; emission, approximately 675-715 nm). Two examiners quantified the areas of GA (mm2) at baseline and at 1-year follow-up using customized segmentation program in Matlab (Mathworks 7.0, Natick, MA, USA) and the reproducibility of the quantifying process was accessed by calculating interclass correlation coefficient (ICC). The mean value of two GA areas measured by each examiner was used to calculate the difference between size at baseline and size at 1-year follow up. Patterns of abnormal FAF in the junctional zone were classified into None or minimal change, Focal, Patchy, Banded, and Diffuse by two other examiners. Multiple regression analysis was used to evaluate the relationship between GA enlargement and abnormal FAF, and binary logistic regression was used to determine predictors of GA enlargement.
Results
The reproducibility of quantification for the areas of GA was statistically significant (ICC 0.95, p < .05). No correlation was found between GA enlargement and abnormal FAF features in multiple regression analysis. Binary logistic regression analysis did not reveal significant risk factor for GA enlargement. However, when the Diffuse pattern of abnormal FAF was compared to pooled data from other patterns of abnormal FAF, the Diffuse pattern was a strong risk factor for GA enlargement (OR = 9.39; p < 0.05).
Conclusions
FAF image acquisition by mFC appears to be adaptable for evaluation in accordance with published classification system. Based on these classification systems, the Diffuse FAF pattern on baseline FAF images indicate a higher risk of GA progression than other patterns in patients with AMD. The identification of high-risk characteristics with mFC is a broadly available method that will provide additional information for predicting the disease course.
Keywords: 412 age-related macular degeneration