Aim To compare standard short-wavelength fundus autofluorescence (SW-FAF) and near infrared-wavelength fundus autofluorescence (NIR-FAF) in detecting geographic atrophy (GA) secondary to age-related macular degeneration, and its retinal sensitivity impairment.
Methods Twenty-five consecutive patients (36 eyes) affected by GA were studied by means of fundus autofluorescence imaging, using both SW-FAF (excitation: 488 nm, emission >500 nm) and NIR-FAF (excitation: 787 nm, emission >800 nm). All patients underwent microperimetry to assess fixation characteristics and retinal sensitivity.
Results In the extrafoveal region, the total hypoautofluorescent (hypo-FAF) area was significantly wider with NIR-FAF than with SW-FAF (8.03±6.68 mm2 vs 7.37±6.34 mm2 respectively; p=0.005). In the foveal area, the total hypo-FAF area was smaller with NIR-FAF than with SW-FAF (0.19±0.03 mm2 versus 0.42±0.12 mm2 respectively; p=0.008). Foveal sparing was larger at NIR-FAF compared with SW-FAF (p=0.021). In nine cases (25%) the site of fixation was hypoautofluorescent on SW-FAF, but normal on NIR-FAF with preserved retinal sensitivity.
Conclusions Standard SW-FAF may overestimate GA in the foveal area, correctly detected by NIR-FAF. In the extrafoveal area, SW-FAF may underestimate GA. Standard SW-FAF should be integrated with NIR FAF when detecting and following GA to avoid inconsistent results and misinterpretation, from both a morphological and functional perspective. Microperimetry helps to quantify retinal sensitivity in GA.
- Geographic atrophy
- age-related macular degeneration
- fundus autofluorescence
- diagnostic tests/investigation
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Linked articles 189498.
Competing interests None.
Patient consent Obtained.
Ethics approval Ethics approval was provided by the Local Ethics Committee of the University of Padua.
Provenance and peer review Not commissioned; externally peer reviewed.