Pilots are at risk for microwave radiation-induced lens damage if they were to repeatedly stand in front of an operating weather radar on the ground. Cataracts are irregular collections of protein densities within the lens. These imperfections distort light flow through the lens. This is analogous to imperfections in a diamond or cracks in a clear ice cube. The lens begins to cloud as a cataract grows.
Cataracts tend to be progressive in size and density, obscuring vision as they grow.
They consolidate in a process called maturation. If the cataract is off the central visual axis, it may not be noticed in daylight when the pupil is small and light passes through the lens without striking the cataract. At night, the pupil opens wider to get more light to the eye. The cataract may bend light entering the periphery of the lens. A person may perceive this as glare or halos around lights at night.