This 86YO female has dry AMD and has subretinal drusenoid deposits (SDD) located above the RPE layer.
Since they are located above the RPE, they are best visualized with blue or green illumination. Notice how the SDD are easily visible on the Optos green channel but disappear in the red channel. Typical drusen (not pictured) would be best seen in the red channel.
The OCT images of a similar (but different patient) illustrate various stages of SDD with outer retinal atrophy.
Learning Points:
Subretinal drusenoid deposits (SDD) are polymorphous light-gray interconnected hypoautofluorescent accumulations located above the RPE. They are present in about one quarter of older adults with healthy maculas and in more than half of those with early to intermediate dry AMD.
Clinically they are often mistaken for conventional drusen and consist of the same lipid-rich membranous debris found in soft drusen. As with drusen, SDD are dynamic and can grow, shrink, resolve, or even recur.
SDDs can appear on OCT as they appear in 3 stages (Zweifel et al, Ophthalmology 2010; 117:303-312) growing upwards from the RPE towards the ELM:
Stage 1- diffusegranular hyperreflective material between the RPE and EZ
Stage 2- material alters the EZ contour
Stage 3- conical, breaking through the EZ
Rod function seems to be preferentially affected, and there is an associated increased risk of delayed dark adaptation, macular pattern dystrophy-like subretinal vitelliform deposits (image 9), geographic atrophy and types 2 and 3 macular neovascularization.
In fact, type 2 neovascularization in the setting of AMD occurs almost solely in eyes with subretinal drusenoid deposits.
