you can try making one using poser primitives....like the cylinder for the glass and that ring primitive for the frame...resize using dials....group em or just parent the cylinder to the ring primitive....then make a texture map for the frame....or you can just use the shader nodes since a monacle isnt that complex anyway....set the transparency of the cylinder and OK you can use a reflection map to get that light reflection on the surface...that's pretty much it for my monacle..... my version is no Colonel Klink monacle but i think itll do....