Correlation between Fundus Autofluorescence and En Face OCT Measurements of Geographic Atrophy.

PURPOSE

To evaluate the correlation between fundus autofluorescence (FAF) and en face spectral-domain OCT (SD-OCT) measurements of geographic atrophy (GA) area associated with age-related macular degeneration.

DESIGN

Retrospective, cross-sectional study.

PARTICIPANTS

Two hundred seventy eyes from 172 subjects with GA associated with age-related macular degeneration.

METHODS

Subjects with atrophic age-related macular degeneration who underwent both FAF (Heidelberg HRA + Spectralis) and dense volume (128 B-scans over 6 × 6 mm) SD-OCT (Cirrus OCT) imaging were included in this retrospective analysis. The borders of all areas of definite decreased autofluorescence (DDAF) corresponding to GA were manually outlined on FAF images by certified graders at Doheny Image Reading Center using validated planimetric grading tools. Geographic atrophy was also automatically delineated using en face OCT (at the level of the choroid) using an instrument software (Cirrus v.6.2), and segmentation errors were manually corrected before the computation of the GA area. The fundus autofluorescence and SD-OCT-derived measurements were correlated.

MAIN OUTCOME MEASURES

Correlation between the SD-OCT and FAF measurements of the GA area.

RESULTS

The mean GA area measured from the FAF images was 8.1 ± 5.04 mm, compared with an automated, uncorrected GA area of 6.82 ± 3.84 mm measured using SD-OCT. Despite the presence of apparent OCT segmentation errors, there was a significant correlation between the FAF and uncorrected SD-OCT measurements (r = 0.80; P < 0.001). After the manual correction of the SD-OCT GA segmentation errors, the measured GA area increased to 7.29 ± 4.18 mm, and the correlation with the FAF-determined GA area significantly improved (r = 0.98; P < 0.001).

CONCLUSIONS

Spectral-domain OCT-derived measurements of GA correlate well with areas of DDAF obtained from FAF images. The manual correction of SD-OCT segmentation errors can further improve this correlation. These observations may support the use of SD-OCT-based measurements of the GA area in clinical research and clinical trials.