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Photophobia is a medical symptom of abnormal intolerance to visual perception of light. [1] As a medical symptom, photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical sensitivity of the eyes, [2] though the term is sometimes additionally applied to abnormal or irrational fear of light, such as ...
Light sensitivity or photosensitivity refers to a notable or increased reactivity to light. Apart from vision , human beings have many physiological and psychological responses to light. In rare individuals an atypical response may result in serious discomfort, disease, or injury.
There are two luminous efficiency functions in common use. For everyday light levels, the photopic luminosity function best approximates the response of the human eye. For low light levels, the response of the human eye changes, and the scotopic curve applies. The photopic curve is the CIE standard curve used in the CIE 1931 color space.
Heliophobia refers to light sensitivity: In psychology, heliophobia is the morbid fear of sunlight; In medicine it can refer to: Hemeralopia, day blindness, inability to see clearly in bright light; Photophobia, an excessive sensitivity of the eyes to sunlight. Notable causes include:
The retina lines the inside of the eye. It is light-sensitive and communicates visual messages to the brain. If the retina detaches, it moves and shifts from its normal position. This can cause photopsia, but can also cause permanent vision loss. Medical attention is needed to prevent vision loss.
Sensitivity of the skin to a light source can take various forms. People with particular skin types are more sensitive to sunburn . Particular medications make the skin more sensitive to sunlight; these include most of the tetracycline antibiotics , heart drugs amiodarone , and sulfonamides .
For the blue-green region (500 nm), 50% of the light reaches the image point of the retina. [2] Adaptation is much faster under photopic vision; it can occur in 5 minutes for photopic vision but it can take 30 minutes to transition from photopic to scotopic. [2] Most older adult humans lose photopic spatial contrast sensitivity.
Most work suggests that the peak spectral sensitivity of the receptor is between 460 and 484 nm. Lockley et al. in 2003 [19] showed that 460 nm (blue) wavelengths of light suppress melatonin twice as much as 555 nm (green) light, the peak sensitivity of the photopic visual system. In work by Zaidi, Lockley and co-authors using a rodless ...