Secondary directions are always oriented to a main direction (fixation). They differ from each other by respectively different spatial values and are significant for the emergence of the spatial sense. A rearrangement of the secondary directions always causes a change in the perception in space. What is the secondary direction? A secondary sense of direction … Secondary Direction: Function, Tasks, Role & Diseases
Fixation lets a person look specifically at an object or subject in external space and is made possible by the retinal site of highest resolution. This so-called fovea centralis represents the main direction of vision. Disorders of fixation are present, for example, in strabismus. What is fixation? By the term fixation, ophthalmology refers to the … Fixation: Function, Tasks, Role & Diseases
Visual acuity is the sharpness with which a visual impression from the environment is imaged on the retina of a living being and processed in its brain. Factors such as receptor density, receptive field size, and the anatomy of the dioptric apparatus affect visual acuity in individual cases. Macular degeneration is one of the most … Visual Acuity: Function, Tasks, Role & Diseases
It is an everyday phenomenon that when entering a dark room, initially poor vision improves as the eyes adapt to the light conditions. This is called dark adaptation and is essential for scotopic vision at night. What is scotopic vision? Scotopic vision refers to seeing in the dark. Scotopic vision refers to seeing in the … Scotopic Vision: Function, Task & Diseases
Near fixation is the visual concentration on a stimulus in the immediate vicinity. The optic pit is the retinal point of sharpest vision and is used for fixation. In addition to the visual pit, the near accommodation of the eye is required for near fixation. What is near fixation? In medicine, near fixation is the … Proximal Fixation: Function, Tasks, Role & Diseases
When reading, the eyes do not move continuously from left to right across the text, but rather jerkily (saccadically) from gaze target to gaze target. In 15 to 20 percent of saccades, a backward saccade, regression, is performed – usually unconsciously – because the text was not fully understood or because the eyes jumped a … Regression of the Eyes: Function, Tasks, Role & Diseases
With the ability of light-dark adaptation, human eyes are able to adapt to lighting conditions. These are two opposing processes of the visual system. Disturbances in light-dark adaptation can occur in vitamin A deficiency and after damage to the central nervous visual pathway. What is light-dark adaptation? With the ability of light-dark adaptation, human eyes … Light-dark Adaptation: Function, Tasks, Role & Diseases
Photopic vision refers to normal color vision via the so-called M, L, and S cones, which are photosensorically optimized for the green, red, and blue regions, respectively. Photopic vision requires a minimum brightness of about 3 to 30 cd/sqm and occurs mainly in the fovea centralis, a small area in the retina. The fovea centralis … Photopic Vision: Function, Task & Diseases
The fovea centralis is the name given to a small depression in the center of the yellow spot of the human retina. It is the region of sharpest vision because the fovea centralis exclusively contains three different types of cones (photoreceptors) for color vision in the wavelength ranges for red, green, and blue. The more … Fovea Centralis: Structure, Function & Diseases
Summation is a bodily process within the visual process. The following article deals with the clarification of terms as well as the function of summation and pursues the question, what do affected persons perceive, in whom the process of summation is disturbed? What are the clinical pictures within this framework? What is summation? Summation is … Summation: Function, Tasks, Role & Diseases