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Photopsia is the presence of perceived flashes of light in the field of vision. It is most commonly associated with: [ 4] Vitreous shrinkage or liquefaction, which is the most common cause of photopsia, causes a pull in vitreoretinal attachments, irritating the retina and causing it to discharge electrical impulses.
Floaters are from objects in pockets of liquid within the vitreous humour, the thick fluid or gel that fills the eye, [ 7] or between the vitreous and the retina. The vitreous humour, or vitreous body, is a jelly-like, transparent substance that fills the majority of the eye. It lies within the vitreous chamber behind the lens, and is one of ...
A posterior vitreous detachment ( PVD) is a condition of the eye in which the vitreous membrane separates from the retina. [ 1] It refers to the separation of the posterior hyaloid membrane from the retina anywhere posterior to the vitreous base (a 3–4 mm wide attachment to the ora serrata ). The condition is common for older adults; over 75% ...
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. While LF may be the result of actual photons of visible light being sensed by the retina, [1] the LF discussed here ...
Photokeratitis or ultraviolet keratitis is a painful eye condition caused by exposure of insufficiently protected eyes to the ultraviolet (UV) rays from either natural (e.g. intense direct or reflected sunlight) or artificial (e.g. the electric arc during welding) sources. Photokeratitis is akin to a sunburn of the cornea and conjunctiva.
Artist's depiction of a scintillating scotoma, exhibiting a flashing visual pattern similar to dazzle camouflage used during WWI. Scintillating scotoma is a common visual aura that was first described by 19th-century physician Hubert Airy (1838–1903). Originating from the brain, it may precede a migraine headache, but can also occur ...
Flicker vertigo. Flicker vertigo, sometimes called the Bucha effect, is "an imbalance in brain-cell activity caused by exposure to low-frequency flickering (or flashing) of a relatively bright light." [ 1] It is a disorientation -, vertigo -, and nausea -inducing effect of a strobe light flashing at 1 Hz to 20 Hz, approximately the frequency of ...
Retinitis. Retinitis is inflammation of the retina in the eye, which can permanently damage the retina and lead to blindness. The retina is the eye's "sensing" tissue. Retinitis may be caused by a number of different infectious agents. Its most common form, called retinitis pigmentosa, has a prevalence of one in every 2,500–7,000 people.