Value is the dimension of lightness/darkness. In terms of a spectral definition of color, value describes the overall intensity or strength of the light. If hue can be thought of as a dimension going around a wheel, then value is a linear axis running through the middle of the wheel, as seen below:
Drusen are tiny yellow or white deposits in a layer of the retina called Bruchs membrane. They are the most common early sign of dry age-related macular degeneration. Drusen are made up of lipids, a type of fatty protein. They may be the result of a failure of the eye to dispose of waste products that are produced when the photoreceptors of the eye drop off older parts of the cell. There are several types of drusen with different levels of risk.
This type of drusen may not cause vision problems for a long time, if at all. âSoftâ drusen are large and cluster closer together. Their edges are not as clearly defined as hard drusen. This soft type of drusen increases the risk for AMD. Drusen of the optic nerve Drusen can also occur in the optic nerve. These drusen are made up of protein and calcium salts and generally appear in both eyes. Unlike the drusen associated with AMD, optic nerve drusen (also known as optic disc drusen) are not related to aging and often appear in children.