Anything resulting in less green, is interpreted as its paired primary color, which is magenta, i.e. an equal mixture of red and blue.Example video which produces a distorted illusion after one watches it and looks away. See motion aftereffect. Positive afterimages
Positive afterimages, by contrast, appear the same color as the original image. They are often very brief, lasting less than half a second. The cause of positive afterimages is not well known, but possibly reflects persisting activity in the brain when the retinal photoreceptor cells continue to send neural impulses to the occipital lobe.A stimulus which elicits a positive image will usually trigger a negative afterimage quickly via the adaptation process. To experience this phenomenon, one can look at a bright source of light and then look away to a dark area, such as by closing the eyes. At first one should see a fading positive afterimage, likely followed by a negative afterimage that may last for much longer. It is also possible to see afterimages of random objects that are not bright, only these last for a split second and go unnoticed by most people. On empty shape
An afterimage in general is an optical illusion that refers to an image continuing to appear after exposure to the original image has ceased. Prolonged viewing of the colored patch induces an afterimage of the complementary color (for example, yellow color induces a bluish afterimage).
The prevalence of hypocholesterolemia in the elderly ranges between 2% to 36%, depending on specific cutoff levels and age range investigated. Alerting physicians to hypocholesterolemia may benefit some of their patients who take cholesterol-lowering drugs and decrease the rate of their emergency room visits. Critical illness
In the setting of critical illness, low cholesterol levels are predictive of clinical deterioration, and are correlated with altered cytokine levels. Causes
Possible causes of low cholesterol are:
statins
hyperthyroidism, or an overactive thyroid gland
adrenal insufficiency
liver disease
malabsorption (inadequate absorption of nutrients from the intestines), such as in celiac disease
malnutrition
abetalipoproteinemia - a rare genetic disease that causes cholesterol readings below 50 mg/dL. It is found mostly in Jewish populations. hypobetalipoproteinemia - a genetic disease that causes cholesterol readings below 50 mg/dL
manganese deficiency
Smith–Lemli–Opitz syndrome
Marfan syndrome
leukemias and other hematological diseases

Diagnosis
Classification
According to the American Heart Association in 1994, only total cholesterol levels below 160 mg/dL or 4.1 mmol/L are to be classified as "hypocholesterolemia". However, this is not agreed on universally and some put the level lower. References


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