(Greek: simple, simply; single, one, once)
It is used to measure, to test, or to stimulate various binocular functions.
It presents separate fields of view to the two eyes while allowing changes in convergence or accommodation of one or both eyes, as well as providing for controls of color, and the intensity or size of the target and field.
2. Referring to a single copy of a gene instead of the customary two copies.
All of the genes on the single X chromosome in the male are in the hemizygous state.