Purpose
To evaluate the correlation between fundus autofluorescence (FAF) and spectral domain optical coherence tomography (SDOCT) measurements in subjects with geographic atrophy (GA).
Methods
The MAHALO study (NCT01229215) enrolled 143 eyes of 143 subjects into a Phase Ib/II multicenter, randomized, sham-injection controlled clinical trial of intravitreal lampalizumab for the treatment of GA secondary to age related macular degeneration (AMD). FAF (Heidelberg HRA or Spectralis) and SDOCT (Cirrus) imaging was obtained at multiple time points, including the baseline visit which is the subject of this analysis. The borders of all areas of definite decreased autofluorescence (DDAF) corresponding to GA were manually outlined on FAF images by certified graders at the Doheny Image Reading Center (DIRC) using using validated planimetric grading tools. GA was also delineated automatically from SDOCT images using instrument software (Cirrus v.6.2), Carl Zeiss Meditec inc., Dublin, CA), and segmentation errors were manually corrected prior to computation of GA area. FAF- and SDOCT- derived measurements were correlated.
Results
The mean baseline GA area measured from FAF images was 8.63 ± 4.22 (range: 2.53 - 17.45) mm2, compared with an automated, uncorrected SDOCT GA area of 7.40 ± 3.53 (range: 0.06 - 15.70) mm2. Despite the presence of apparent OCT segmentation errors, there was significant correlation between FAF and uncorrected SDOCT measurements (r = 0.81; P <0.001). Following manual correction of SDOCT GA segmentation, the measured GA area increased to 7.92 ± 3.60 (SD; range: 2.20 - 15.70), and the correlation with FAF-determined GA area significantly improved (r = 0.97; P < 0.001).
Conclusions
SDOCT-derived measurements of GA correlate well with areas of DDAF obtained from FAF images. Manual correction of SDOCT segmentation errors can further improve this correlation.
Keywords: 412 age-related macular degeneration •
688 retina •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)