Zonular cataracts include specific regions of the lens and include nuclear cataracts, which affect the fetal or embryonic lens nucleus and lamellar cataracts. These tend to affect lens fibers that are formed at the same time, resulting in a shell like opacity. Zonular cataracts can also be characterized as dense or pulverulent (dusty appearing), and can be accompanied by arcuate opacities extending into the lens cortex, called cortical riders.