Abstract
Purpose::
To investigate retinal thickness, fundus autofluorescence (FA) changes and macular sensitivity in patients with early age-related macular degeneration (AMD) with high risk characteristics (HRC).
Methods::
Patients with early AMD fundus changes with HRC (large drusen and focal hyperpigmentation) were studied. Inclusion criteria were central and stable fixation, and visual acuity of 20/40 or better. A 10° area (3000 micrometers) centred onto the fovea was studied with OCT3 (Stratus-OCT, Zeiss, Humphrey Instruments, Germany) and microperimetry (MP1; Nidek Technologies, Padova, Italy). Changes of FA were recorded with confocal scanning laser ophthalmoscope (Heidelberg Retina Angiograph, HRA, Heidelberg Engineering, Dossenheim, Germany). Retinal thickness was measured in the same macular points tested by MP1, and correlated to HRC and changes in AF.
Results::
Twenty-nine consecutive patients were studied. Increase of FA was significantly correlated to the presence of drusen and focal hyperpigmentation (r=0.72), especially when both characteristics were simultaneously present (p<0.0001). Increased or decreased FA was significantly correlated to the reduction of retinal sensitivity over the same areas (r= 0.75), but not to retinal thickness at OCT. A significantly loss of retinal sensitivity was detected over large drusen associated with focal hyperpigmentation (p<0.001). Retinal thinning was present over large drusen or focal hyperpigmentation, but it was not detected when both characteristics were simultaneously present. In the central fovea the reduction of retinal thickness was significantly related to the presence of large drusen (114.39µm +16.4 vs 199.79µm + 33.7 in the foveal area with no large drusen).
Conclusions::
In early AMD eyes with HRC there is a significant correlation between morphological and functional changes. The reduction of retinal thickness is caused by the thinning of the photoreceptor layer over large drusen in the foveal region. In macular areas with HRC retinal sensitivity deteriorates earlier than retinal thinning, particularly when HRC are associated with FA changes, documenting the functional impact of these lesions.
Keywords: age-related macular degeneration • perimetry • drusen