Insights into pathology of cuticular drusen from integrated confocal scanning laser ophthalmoscopy imaging and corresponding spectral domain optical coherence tomography

To analyze the integrated confocal scanning laser ophthalmoscopy (cSLO) fundus and angiographic imaging and corresponding spectral domain optical coherence tomography (SD-OCT) features of cuticular drusen. Twenty-one consecutive patients with cuticular drusen were submitted to cSLO fundus and angiographic imaging [infrared reflectance (IR), fundus autofluorescence (FAF), near-infrared autofluorescence (NIA), fluorescein angiography (FA), and indocyanine green angiography (ICGA)) and "eye-tracked" SD-OCT. A total of 42 eyes were included for analysis. BCVA ranged from 20/20 to 20/400. In 5/42 eyes, cSLO imaging and corresponding SD-OCT showed coincident vitelliform macular detachment, and in 9/42 eyes showed coincident geographic atrophy (GA). The "typical" cuticular drusen, intensely staining on early FA phase ("stars-in-the-sky" appearance in the fundus), appeared as "sawtooth" retinal pigment epithelium (RPE) elevation on SD-OCT. Some "atypical" cuticular drusen appeared, on early FA and ICGA frames, as hyper-fluoresecent lesions surrounded by faint hypo-fluoresecent halos. These lesions, which became intensely hyper-fluorescent in the late FA and ICGA phases, appeared, on SD-OCT, as small, confluent "dome-shaped" RPE elevations. Interestingly, some less intensely staining cuticular drusen (FA and ICGA) appeared as irregular slight thickening of RPE/Bruch's membrane complex on SD-OCT scans. Integrated imaging makes it possible to highlight different features within cuticular drusen-containing regions, and gives insights into pathology. We suggest that "typical" cuticular drusen may represent a continuous layer of early basal laminar deposit (BLamD) associated with membranous debris accumulation. As early BLamD thicken, the lesions become richer in solid lipid particles, and "atypical" cuticular drusen may develop.