Figure 4From: The fundus slit lamp “Lens sandwich” of altogether +55D power (+20/+20/+15D from lens trial set). The quality of this “lens sandwich” suffices for adequate diagnosis of the disease condition despite its obvious suboptimal optical properties (in comparison to a single aspheric lens made from glass) - see also Figure 3 (+55D is the power of the original el Bayadi lens (El Bayadi 1953)).Back to article page