Foveal Sparing of Reticular Drusen in Eyes With Early and Intermediate Age-Related Macular Degeneration

To analyze the central distribution of reticular drusen (RDR) in eyes with early and intermediate AMD without soft drusen or pigmentary changes within the central subfield using confocal scanning laser ophthalmoscopy (cSLO) and spectral-domain optical coherence tomography (SD-OCT). Fifty-two eyes of 46 subjects (median age: 76.3 years, interquartile range [IQR], 71-80) were examined by simultaneous combined near-infrared cSLO and raster SD-OCT imaging. The appearance and the topographic distribution of RDR were analyzed within the macula area using the Early Treatment Diabetic Retinopathy Study grid. In addition, longitudinal examinations during an observation period of at least 6 months were included (median observation time: 1.5 years, IQR, 0.9-2.8). The RDR involvement within the central subfield (46%) was less compared with the surrounding subfields (62%-100%), slices (67%-100%), and zones (94%-100%) (P < 0.001). RDR were typically distributed as one continuous zone around the fovea in an incomplete or complete ring-shaped pattern, whereas the fovea itself was either spared or only a few lesions were present. Over time, the RDR density increased and new RDR lesions occurred at the border of the RDR zone toward a closure of the ring-shaped pattern. Within the fovea, development of RDR was observed in 8 of 28 eyes. The fovea appears to be less vulnerable to RDR development as compared with peripheral macula areas. Factors for initial sparing of the foveal retina are yet unknown but may relate to topographic differences of choroidal blood flow and/or photoreceptor distribution.