Science Buddies: "Ask an Expert"

Is there a way to measure dark adaptation of the human vision without using professional devices?

Hi newlegna,

Interesting question. I would think you could do it by a bit of trial and error in a dark room with a piece of white cardboard. The problem would be to provide just enough light so that the person would not be able to see the cardboard until their eyes became dark-adapted. You would have to experiment with light sources till you found one that was just bright enough, but not too bright. You would also need to standardize the light source that was used BEFORE the room was darkened. It has to be bright enough that a minute or so elapses before the subjects eyes can adapt to the dark.

The variable that you would measure is the time it takes for people to see a white shape in the dark after a light has been switched off. Here’s a weblink that gives some information about the dark adaptation process: http://webvision.med.utah.edu/book/part ... daptation/

Let me know how you decide to do this. Do you have a hypothesis yet? Age is one factor in ability to dark-adapt quickly. I wonder if there’s a difference between males and females.

Best wishes,

Sybee