A cataract is a cloudiness in the lens of the eye. Is light dispersed or diffused by it?

Dispersion of light is the phenomenon of light separating into its component colors. When white light travels through a glass prism, it is called refraction. It disperses into a swath of many colors known as the spectrum of light. Violet, Indigo, Blue, Green, Yellow, Orange, and Red are the colors of the light spectrum.

Diffusion is the movement of molecules in the presence of a concentration gradient. It is a vital process that occurs in all living things. Diffusion is a process that aids in the movement of molecules into and out of cells. The molecules travel from a high-concentration zone to a low-concentration region until the concentration is uniform throughout.

The dispersion of the light occurs only through a transparent medium, where in the event where the light can pass through a given medium; the light would split it into its color components, whereas if white sunlight passes through a medium, it would split into seven colors; this is due to the fact the angle refraction is a function of the wavelength of the light, hence each of the components of the white light, would refract at different angles, hence the dispersion of the light phenomena.

Diffusion, on the other hand, occurs when light is being scattered back in a direction opposite to the direction of wave incidence; if all the light is reflected making an angle with the normal equal to the angle of incidence, then this is a reflection, if the different light wave is being reflected in a different direction, then it’s a diffusion reflection.

And as the light wave enters the clouded lens, and due to the inhomogeneity of the transparency of the lens medium, i.e., the lens composes of transparent and opaque regions, the lights would get scattered in different directions, hence the light is said to be diffused by the clouded lens.

Therefore, the light is diffused.