Background: Early Age Related Macular Degeneration (early AMD) has been correlated to different functional alterations, but the exact relationship between fundus lesions and overlying sensitivity is poorly known. The aim of this study was to compare fundus-related sensitivity (microperimetry) and fundus autofluorescence (FAF) of macular area with drusen and pigment abnormalities in early AMD.
Methods: Thirteen consecutive patients with early AMD and visual acuity of 20/20 were studied by means of microperimetry which automatically analyzes macular light differential threshold and fixation patterns. Fundus colour photo and FAF of macular area were recorded on the same day. MP was exactly (topographically) superimposed over FAF images.
Results: Macular sensitivity significantly decreased over large drusen (11.2dB+5.6, p< 0.0001), and over pigment abnormalities (13.1dB+3.6, p<0.0001). When both characteristics were present reduction was higher if compared to its absence (9.6dB+4.3, vs 15.0dB+4.5, p<0.0001). Sensitivitity reduction was significant in areas with altered FAF when compared to areas with normal FAF (p<0.0001).
Conclusions: Increased FAF in early AMD have a functional correlate exactly quantified by microperimetry. In retinal areas affected by early AMD retinal sensitivity deteriorates, despite good visual acuity. Microperimetry may allow early detection of functional impairment due to these lesions. Both MP and FAF may be useful to monitor AMD progression.
- early age related macular degeneration
- fundus autofluorescence