Results of Multimodal Imaging of Dry AMD
This study sought to explain the clinical significance of near-infrared reflectance (NIR), blue fundus autofluorescence (FAF) and near-infrared autofluorescence (NIA) in dry age-related macular degeneration (AMD) by correlation with fluorescein angiography (FA) and cross-sectional spectral domain optical coherence tomography (SD OCT).
A total of 110 eyes (62 patients, mean age: 64 ± 8 years) diagnosed with dry AMD between January 2010 and December 2010, which underwent NIR (Λ = 830 nm), FAF and FA (excitation Λ = 488 nm; emission Λ > 500 nm), NIA (excitation Λ = 787 nm; emission Λ > 800 nm), and simultaneous SD OCT scanning using a combined confocal scanning laser ophthalmoscope/SD OCT device (Spectralis HRA + OCT; Heidelberg Engineering) were examined.
Drusen showed variable increased/decreased NIR, FAF, NIA and FA, which corresponded to variable increased/decreased thickness of the retinal pigment epithelium (RPE) and possible presence of subretinal deposits on SD OCT. It was noted that geographic atrophy (GA) was present in 43/110 eyes (39.0%) and showed increased NIR and fluorescence (FA), absent FAF and NIA, and loss of RPE on SD OCT. The hyperautofluorescence of the GA margin was never larger in FAF than that in NIA, while in 16.2% of cases, it was larger in NIA than that in FAF and corresponded to mild choroidal hyperreflectivity on SD OCT.
In conclusion, simultaneous recording of SD OCT scans provided ultrastructural data for the evaluation of NIR, FAF, NIA and FA in dry AMD. Near-infrared autofluorescence might detect earlier than FAF areas of RPE cell loss at the GA margin.