- the reflex adaptation of the eye to dim light, consisting of a dilatation of the pupil and an increase in the number of functioning rods accompanied by a decrease in the number of functioning cones (opposed to light adaptation).
Origin of dark adaptation
First recorded in 1905–10
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- The adjustment of the eye under reduced illumination, in which sensitivity to light is greatly increased.scotopic adaptation
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.