Question

What is meant by light and dark adaptation? How do they take place?

Answer 1

Light and dark adaptation of the eye

Explanation:

• Eyes can adjust and visualize a wide range of light intensity levels by visual adaptation. These adaptations take place due to the action of the rhodopsin, a photochemical present in retina.
• Light adaptation is the adaption of the eye to adjust to bright light immediately after an exposure of dim light.
• When bright light is introduced, this chemical is broken down and bleached leading to a glare of bright white light immediately and this happens within 1 to 2 minutes.  
• Dark adaptation adapts the eye to adjust to dim light after an exposure to bright light.
• Here, the rhodopsin is regenerated which takes a longer time to about half an hour or more

Answer 2

Answer:

Light adaptation is the process of adjusting to bright light after exposure to dim light. This process often takes a minute or two to be completed. Dark adaptation, on the other hand, refers to the process of adjusting to dim light after exposure to bright light. It may take half an hour or longer depending upon the level of exposure.

Light and dark adaptation takes place due to photochemical processes. Light adaptation takes place when the molecules of rhodopsin or visual purple in the rods of the eye get bleached or broken down, as a result of the action of light. Dark adaptationtakes place when the light is removed allowing for restorative processes that regenerate the pigment in the rods with the help of vitamin A.