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Scotopic vision is produced exclusively through rod cells, which are most sensitive to wavelengths of around 498 nm (blue-green) [3] and are insensitive to wavelengths longer than about 640 nm. [4] Under scotopic conditions, light incident on the retina is not encoded in terms of the spectral power distribution .
The visible range of light is defined by what is readily perceptible to humans, thought the visual perception of non-humans often extends beyond the visual spectrum. The resulting perception is also known as vision, sight, or eyesight (adjectives visual, optical, and ocular, respectively).
A reference value above which visual acuity is considered normal is called 6/6 vision, the USC equivalent of which is 20/20 vision: At 6 metres or 20 feet, a human eye with that performance is able to separate contours that are approximately 1.75 mm apart. [9] Vision of 6/12 corresponds to lower performance, while vision of 6/3 to better ...
Above a certain luminance level (about 0.03 cd/m 2), the cone mechanism is involved in mediating vision; photopic vision. Below this level, the rod mechanism comes into play providing scotopic (night) vision. The range where two mechanisms are working together is called the mesopic range, as there is not an abrupt transition between the two ...
Rods primarily mediate scotopic vision (dim conditions) whereas cones primarily mediate photopic vision (bright conditions), but the processes in each that supports phototransduction is similar. [1] The intrinsically photosensitive retinal ganglion cells were discovered during the 1990s. [2]
Photopic vision is characteristic of the eye's response at luminance levels over three candela per square metre. Scotopic vision occurs below 2 × 10 −5 cd/m 2. Mesopic vision occurs between these limits and is not well characterised for spectral response. [2] [1]
An animated sequence of simulated appearances of a red flower (of a zonal geranium) and background foliage under photopic, mesopic, and scotopic conditions. The Purkinje effect or Purkinje phenomenon (Czech: [ˈpurkɪɲɛ] ⓘ; sometimes called the Purkinje shift, often pronounced / p ər ˈ k ɪ n dʒ i /) [1] is the tendency for the peak luminance sensitivity of the eye to shift toward the ...
The standard scotopic luminous efficiency function or V ′ (λ) was adopted by the CIE in 1951, based on measurements by Wald (1945) and by Crawford (1949). [15] Luminosity for mesopic vision, a wide transitioning band between scotopic and phototic vision, is more poorly standardized. The consensus is that this luminous efficiency can be ...