Search results
Results from the WOW.Com Content Network
Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the visual field, which prevents vision within the scotoma area. It typically affects both eyes, as it is not a problem specific to one eye.
Closed-eye hallucinations and closed-eye visualizations ( CEV) are hallucinations that occur when one's eyes are closed or when one is in a darkened room. They should not be confused with phosphenes, perceived light and shapes when pressure is applied to the eye's retina, or some other non-visual external cause stimulates the eye.
Prosopometamorphopsia (sometimes known as "demon face syndrome") is a visual disorder characterized by altered perceptions of faces. In the perception of a person with the disorder, facial features are distorted in a variety of ways including drooping, swelling, discoloration, and shifts of position.
Neurology, ophthalmology. Diplopia is the simultaneous perception of two images of a single object that may be displaced horizontally or vertically in relation to each other. [1] Also called double vision, it is a loss of visual focus under regular conditions, and is often voluntary.
Aniseikonia. Aniseikonia is an ocular condition where there is a significant difference in the perceived size of images. It can occur as an overall difference between the two eyes, or as a difference in a particular meridian. [1] If the ocular image size in both eyes are equal, the condition is known as iseikonia. [2]
Scotopic vision. In the study of visual perception, scotopic vision (or scotopia) is the vision of the eye under low- light conditions. [1] The term comes from the Greek skotos, meaning 'darkness', and -opia, meaning 'a condition of sight'. [2] In the human eye, cone cells are nonfunctional in low visible light.
Superior oblique myokymia is a neurological disorder affecting vision and was named by Hoyt and Keane in 1970. [1] It is a condition that presents as repeated, brief episodes of movement, shimmering or shaking of the vision of one eye, a feeling of the eye trembling, or vertical/tilted vision.
Causes. Anisometropia is caused by common refractive errors, such as astigmatism, far-sightedness, and myopia, in one eye. [6] Anisometropia is likely the result of both genetic and environmental influences. [7] Some studies suggest, in older adults, developing asymmetric cataracts may cause worsen anisometropia.
Kaleidoscope. A toy kaleidoscope. A kaleidoscope ( / kəˈlaɪdəskoʊp /) is an optical instrument with two or more reflecting surfaces (or mirrors) tilted to each other at an angle, so that one or more (parts of) objects on one end of these mirrors are shown as a regular symmetrical pattern when viewed from the other end, due to repeated ...
Causes: Peripheral (Posterior) vitreous detachment, retinal detachment, age-related macular degeneration, ocular (retinal) migraine / migraine aura, vertebrobasilar insufficiency, optic neuritis, occipital lobe infarction (similar to occipital stroke), sensory deprivation (ophthalmopathic hallucinations) Risk factors