From the light into the dark, the human eye's sensitivity to light gradually increased, reaching the maximum in about 30 minutes, said dark adaptation. Dark adaptation is a reflection of the basic function of the visual cell - sensitization. In the absence of nutrients and retinal lesions, dark adaptations often occur. Dark adaptation measurement is one of the important items for eye function tests.
concept
When we walk from a bright place into a dark place, our eyes will not see anything at all. It will take a while before we will gradually adapt and gradually see things in the dark. This process is about 30. The adaptation process in which the sensitivity of the retina is gradually increased during ~40 minutes is dark adaptation, that is, the ability of the retina to adapt to the darkness.
Cause
In dark places, cones in the human eye are inactive, and only rod photoreceptors are at work. In rod photoreceptor cells, there is a substance called rhodopsin, which is sensitive to weak light and can be gradually synthesized in the dark. According to eye expert statistics, 60% of rhodopsin can be generated within 5 minutes in the dark. It takes about 30 minutes to generate all. Therefore, the longer the time spent in a dark place, the higher the sensitivity to low light. However, some people have obstacles in the function of rod-shaped photoreceptor cells. In dark areas, rod-shaped pigment cells cannot work normally. No matter how long he stays in the dark, he cannot increase sensitivity to low light. We take this phenomenon. Called night blindness. Some night blindness is caused by factors such as vitamin A deficiency, and some are caused by diseases such as primary retinitis pigmentosa. Rod photoreceptors do not have the ability to identify the color of an object, so looking at things in the dark is a color.
Dark reaction
Dark adaptation is a phenomenon in which the retina has increased visual acuity when it adapts to a dark place or a low light intensity state, and is a corresponding word for light adaptation. The light that can't be seen from the light suddenly entering the darkness can gradually be seen with the extension of the stay in the dark. This is a daily phenomenon.
The time course of dark adaptation can be accurately determined by psychophysical methods for humans. After giving sufficient adaptation in advance and turning the room into a darkroom and measuring the time course of changes in the test light threshold, a dark adaptation curve can be obtained.
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