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. [5] [6] The affected area flickers but is not dark. It then gradually expands outward ...
One example of a pressure phosphene is demonstrated by gently pressing the side of one's eye and observing a colored ring of light on the opposite side, as detailed by Isaac Newton. [ 7 ] [ 8 ] [ 9 ] Another common phosphene is "seeing stars" from a sneeze , laughter, a heavy and deep cough, blowing of the nose , a blow on the head or low blood ...
Photopsia is the presence of perceived flashes of light in the field of vision. It is most commonly associated with: [4] posterior vitreous detachment; migraine aura (ocular migraine / retinal migraine) migraine aura without headache; scintillating scotoma; retinal break or detachment; occipital lobe infarction (similar to occipital stroke)
They may include fully formed images, such as human figures or scenes, angelic figures, or unformed phenomena, like flashes of light or geometric patterns. [2] [3] Visual hallucinations are not restricted to the transitional states of awakening or falling asleep and are a hallmark of various neurological and psychiatric conditions. [3]
Floaters drift around your field of vision and dart away when you try to look at them directly, eventually settling at the bottom of your eye and out of your sightline. Floaters appear when the ...
Cosmic ray visual phenomena, or light flashes (LF), also known as Astronaut's Eye, are spontaneous flashes of light visually perceived by some astronauts outside the magnetosphere of the Earth, such as during the Apollo program.
Magnetophosphenes are flashes of light that are seen when one is subjected to a changing magnetic field such as when in an MRI. This changing field causes current within the retina or visual cortex resulting in the illusion of light. [1] In one series, 8 out of 1023 people having an MRI experienced flashing lights. [2]
A test called flourescein angiography uses a special dye and camera to study blood flow in the back layers of the eye. When a person has multifocal choroiditis (MFC), lesions in the eye will appear as fluorescent spots. Visual field tests may also show an enlarged blind spot or a decrease in visual clarity.