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
Human eyes are constantly in motion. In this process, the eyeballs turn consciously or unconsciously in different directions and perceive different objects arbitrarily or involuntarily. This happens through the reception of all visual stimuli by both eyes, which as a functional unit make three-dimensional vision possible. A distinction is made between vergence movements and conjugate … Saccade: 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
The atlas is the first cervical vertebra that supports the skull. It forms an articulated connection with the parietal bone. Fractures in the area of the atlas ring can destroy the medulla oblongata, causing death. What is the atlas? The cervical spine of humans and most other mammals consists of a total of seven vertebrae. … Atlas: Structure, Function & Diseases
Eye movement serves all aspects of vision and is also partially controlled by reflexes triggered by self-motion, such as detecting and tracking an object. In this process, the image is placed and held in the center of the yellow spot, which is the fovea. As soon as an object moves, subsequent movements of the eye … Eye Follow Movement: Function, Task & Diseases
The autokinetic effect corresponds to an optical illusion. When a static light stimulus is delivered in an otherwise monochromatically dark environment, humans lack reference points for judging the localization and motion of the light spot. This creates the impression that the static stimulus is moving in the environment. What is the autokinetic effect? Human visual … Autokinetic Effect: Function, Tasks, Role & Diseases
Microsaccades are minimal movements of the eyes that play a crucial role in visual perception. Without one microsaccade per second, the brain does not achieve visual perception because only microsaccades provide a shift of light on the retina. This shift is important for the retinal receptors to relay visual information to the brain. What are … Microsaccades: Function, Task & Diseases
In principle, the eyes can be rotated about all three possible axes of rotation in three-dimensional space, within certain limits. Parallel eye movements of both eyes, with identical rotations with respect to the axis of rotation and number of degrees, are called conjugate eye movements. They usually occur unconsciously and arise, for example, as gaze-following … Conjugate Eye Movements: Function, Task & 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
