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Convergence insufficiencyis a sensory and neuromuscular anomaly of the binocular visionsystem, characterized by a reduced ability of the eyesto turn towards each other, or sustain convergence. Symptoms. [edit] The symptoms and signs associated with convergence insufficiency are related to prolonged, visually demanding, near-centered tasks. They ...
In convergence insufficiency near point of convergence will recede, and positive fusional vergence (PFV) will reduce. So, the patient uses excessive accommodation to stimulate accommodative convergence to overcome reduced PFV. Risk factors. A large amount of near work is the main precipitating factor of accommodative excess.
Parinaud's syndrome is a cluster of abnormalities of eye movement and pupil dysfunction, characterized by: Paralysis of upwards gaze: Downward gaze is usually preserved. This vertical palsy is supranuclear, so doll's head maneuver should elevate the eyes, but eventually all upward gaze mechanisms fail. In the extreme form, conjugate down gaze ...
Light from a single point of a distant object and light from a single point of a near object being brought to a focus. The accommodation reflex (or accommodation-convergence reflex) is a reflex action of the eye, in response to focusing on a near object, then looking at a distant object (and vice versa), comprising coordinated changes in vergence, lens shape (accommodation) and pupil size.
Spasm of accommodation. A spasm of accommodation (also known as a ciliary spasm, an accommodation, or accommodative spasm) is a condition in which the ciliary muscle of the eye remains in a constant state of contraction. Normal accommodation allows the eye to "accommodate" for near-vision. However, in a state of perpetual contraction, the ...
A common form of exotropia is known as "convergence insufficiency" that responds well to orthoptic vision therapy including exercises. This disorder is characterized by an inability of the eyes to work together when used for near viewing, such as reading. Instead of the eyes focusing together on the near object, one deviates outward.
Vergence-accommodation conflict ( VAC ), also known as accommodation-vergence conflict, is a visual phenomenon that occurs when the brain receives mismatching cues between vergence and accommodation of the eye. This commonly occurs in virtual reality devices, augmented reality devices, 3D movies, and other types of stereoscopic displays and ...
Vergence. The two eyes converge to point to the same object. A vergence is the simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision. [ 1] When a creature with binocular vision looks at an object, the eyes must rotate around a vertical axis so that the projection of the image is in the centre of ...