Abstract
Purpose: :
To characterize reticular drusen (RD) in patients with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) in the multicenter, prospective natural history GAP-study using confocal scanning laser ophthalmoscopy (SLO) and spectral-domain optical coherence tomography (SD-OCT) imaging.
Methods: :
Three-field fundus autofluorescence (FAF, exc = 488, em 500 - 700 nm), near-infrared reflectance (NIR, = 830 nm), and blue reflectance (BR, = 488; Heidelberg Retina Angiograph/Spectralis, Heidelberg Engineering, Germany) images were recorded in 1104 eyes of 552 patients with GA (age 77.1 ± 7.7 years) in addition to color fundus photographs. Two independent readers evaluated baseline images for prevalence and topographic distribution of reticular drusen using a modified Early Treatment Diabetic Retinopathy Study (ETDRS) grid. In case of discrepancy, a third grader was asked to arbitrate. In a subset of 23 patients, simultaneous SD-OCT imaging was performed.
Results: :
RD were present in 326 of 552 (59.1%) patients in at least one eye and with at least one cSLO imaging modality (bilateral 234 [71.8%]). For each modality separately, prevalence of reticular drusen and kappa-statistics for interobserver reliability were as follows: IR 46.4% and 0.73, FAF 40.9% and 0.77, BR 21.3% and 0.63 (values for right eyes only, left eyes showed similar data). Systematic analysis of the topographic distribution using three-field FAF imaging (201 right eyes) demonstrated the presence of RD most frequently superior to the fovea (99.0%). In 85 (42.3%) right eyes, reticular drusen occurred nasal to the optic nerve head. SD-OCT imaging revealed alterations anterior to the RPE cell monolayer including focal deposits, hyperreflective migrating structures, regular wavy patterns, and fusing of bands 2-4.
Conclusions: :
RD represents a common phenotypic hallmark in eyes with GA secondary to AMD. In contrast to fundus photographs, RD are readily identified in various cSLO imaging modes. This may explain the high prevalence determined herein in contrast to previous reports based on fundus photographs. The corresponding morphological substrate in the outer neurosensory retina on high-resolution SD-OCT would reflect a disease process at the level of the photoreceptors rather than the biogenesis of the ‘conventional’ drusen phenotypes in the sub-retinal pigment epithelium space and in the inner aspects of Bruch’s membrane.
Clinical Trial: :
www.clinicaltrials.gov NCT00599846
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: prevalence/incidence • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)