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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 ...
Presbyopia is physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. [ 4] Also known as age-related farsightedness [ 5] (or age-related long sight in the UK [ 6] ), it affects many adults over the age of 40.
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 ...
We've all grown up thinking that sitting too close to the television is damaging to our eyes ... but that might not be the case. Technology spawns lots of confusion ... and a few affectionately ...
Eye tracking device is a tool created to help measure eye and head movements. The first devices for tracking eye movement took two main forms: those that relied on a mechanical connection between participant and recording instrument, and those in which light or some other form of electromagnetic energy was directed at the participant's eyes and its reflection measured and recorded.
Pupillary light reflex. Variation in the size of the pupil in bright (left) and dim (right) environments. In this case the pupil is 3 mm in diameter on the left, and 9 mm on the right. The pupillary light reflex ( PLR) or photopupillary reflex is a reflex that controls the diameter of the pupil, in response to the intensity ( luminance) of ...
Blue light, a type of high-energy light, is part of the visible light spectrum. High-energy visible light (HEV light) is short-wave light in the violet/blue band from 400 to 450 nm in the visible spectrum, which has a number of purported negative biological effects, namely on circadian rhythm and retinal health (blue-light hazard), which can lead to age-related macular degeneration.
Adaptation (eye) In visual physiology, adaptation is the ability of the retina of the eye to adjust to various levels of light. Natural night vision, or scotopic vision, is the ability to see under low-light conditions. In humans, rod cells are exclusively responsible for night vision as cone cells are only able to function at higher ...