dark adaptation is easy. To see in low light levels, you need to be in low light levels for a period (depending on your age) of about 20-30 minutes. If you are exposed to normal or bright light, even for a brief period, you have to start over. It was standard practice for me to stand a deck watch at night to adapt before I went on watch.
Accomodation: This is where the normal eye adjusts the thickness of the lens to focus on the object, whatever its range is. My digital camera does a good job of it also.
could anyone give me the meaning of accommodation and dark adaptation?
2 answers
I searched Google under the key words "visual accommodation" and "dark adaptation"to get these possible sources:
http://www.ski.org/Vision/glossary.html#V
http://www.answers.com/topic/accommodation?cat=health
http://webvision.med.utah.edu/light_dark.html
http://www.yorku.ca/eye/darkada1.htm
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
To see the effect of dark adaptation, you can keep one eye closed for a period of time in a well-lighted room. Then go into a darkened room or closet, so the opened eye has trouble seeing. Now open the dark-adapted eye. The difference will be greater, if the time the one eye was closed is longer.
If you anticipate going into a darkened area, you can at least partially dark adapt by closing one eye for a period of time before entering that area. (Since most of your depth perception cues are monocular [one-eyed], you don't need to worry about bumping into things while you are still in the lighted area.) Try it!
I hope this helps a little more. Thanks for asking.
http://www.ski.org/Vision/glossary.html#V
http://www.answers.com/topic/accommodation?cat=health
http://webvision.med.utah.edu/light_dark.html
http://www.yorku.ca/eye/darkada1.htm
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
To see the effect of dark adaptation, you can keep one eye closed for a period of time in a well-lighted room. Then go into a darkened room or closet, so the opened eye has trouble seeing. Now open the dark-adapted eye. The difference will be greater, if the time the one eye was closed is longer.
If you anticipate going into a darkened area, you can at least partially dark adapt by closing one eye for a period of time before entering that area. (Since most of your depth perception cues are monocular [one-eyed], you don't need to worry about bumping into things while you are still in the lighted area.) Try it!
I hope this helps a little more. Thanks for asking.