A method for using relay lenses with display monitors for vision testing at far and near

• Published in: Optometry and vision science Vol. 77; no. 2; pp. 102 - 104
• Main Author: KATZ, M
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.02.2000
• Subjects: Biological and medical sciences; Computer Terminals; Eyeglasses; Humans; Hyperopia - diagnosis; Investigative techniques of ocular function and vision; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Myopia - diagnosis; Refraction, Ocular; Reproducibility of Results; Vision Tests - instrumentation; Visual Acuity; Human; Sensitivity; Far vision; Visual acuity; Exploration; Near vision; Contrast; Display screen
• ISSN: 1040-5488; 1538-9235
• DOI: 10.1097/00006324-200002000-00015

Resolution limitations preclude the use of display monitors for near testing of acuity and contrast sensitivity. Relay lenses can form minified aerial images of the display at any given near viewing distance, but the image will differ in spatial frequency from the display. Equations are presented that can be used to specify the far- and near-viewing distances and the necessary focal length of a lens so that the display and its near aerial image have identical spatial frequencies when viewed by a subject at a fixed location. Modulation transfer function (MTF) calculations show that achromatic doublets will not degrade the resolution across a 300-mm wide display, thereby providing the versatility of display monitors for near vision testing.