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Prism (optics) A familiar dispersive prism. An optical prism is a transparent optical element with flat, polished surfaces that are designed to refract light. At least one surface must be angled — elements with two parallel surfaces are not prisms. The most familiar type of optical prism is the triangular prism, which has a triangular base ...
Magnetic resonance imaging. Hemianopsia, or hemianopia, is a visual field loss on the left or right side of the vertical midline. It can affect one eye but usually affects both eyes. Homonymous hemianopsia(or homonymous hemianopia) is hemianopic visual field loss on the same side of both eyes. Homonymous hemianopsia occurs because the right ...
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 acephalgically (without headache), also known as visual migraine or migraine aura. [ 4]
Prism dioptres. Prism correction is commonly specified in prism dioptres, a unit of angular measurement that is loosely related to the dioptre. Prism dioptres are represented by the Greek symbol delta (Δ) in superscript. A prism of power 1 Δ would produce 1 unit of displacement for an object held 100 units from the prism. [2]
8.7% global prevalence in 2020 [ 2] Macular degeneration, also known as age-related macular degeneration ( AMD or ARMD ), is a medical condition which may result in blurred or no vision in the center of the visual field. [ 1] Early on there are often no symptoms. [ 1] Over time, however, some people experience a gradual worsening of vision that ...
Cortical blindness is the total or partial loss of vision in a normal-appearing eye caused by damage to the brain 's occipital cortex. [ 1] Cortical blindness can be acquired or congenital, and may also be transient in certain instances. [ 2] Acquired cortical blindness is most often caused by loss of blood flow to the occipital cortex from ...
Hemianopsia. Hemianopsia. Paris as seen with full visual fields. Specialty. Ophthalmology, neurology. Hemianopsia, or hemianopia, is a loss of vision or blindness ( anopsia) in half the visual field, usually on one side of the vertical midline. The most common causes of this damage are stroke, brain tumor, and trauma.
This can affect one or both eyes and different parts of the eye, such as the iris, lens, or retina. Coloboma can cause vision loss and sensitivity to light, which Nedoroscik has also posted about ...