TABLE OF CONTENTS A knowledge of the characteristics of the human eye is important to the practice of optical engineering because the majority of optical systems utilize the eye as the final element of the system in one way or another. Thus, it is vital that the designer of an optical system understand what the eye can and cannot accomplish. For example, if a visual optical system is required to recognize a certain size target or to measure to a certain degree of accuracy, the magnification of the image presented to the eye must be sufficient to allow the eye to detect the necessary details. On the other hand, it would be wasteful to design a system with a perfection of image rendition which the eye could not utilize.
The human eye is a living optical system and its characteristics vary widely from individual to individual. For a given individual, the characteristics may vary from day to day, indeed from hour to hour. Therefore, the data presented in this chapter must be considered as central values in a range of values; in fact, some data are useful only as an indication of the order of magnitude of a certain characteristic. The conditions under which the eye is used play a large role in determining the behavior of the eye and must always be taken into account.
In physiological optics, the unit of measure for the power of a lens or optical system is the diopter, the abbreviation for which...
