Related Experiment Video
Updated: Aug 17, 2026

Measuring the Behavioral Effects of Intraocular Scatter
Published on: February 18, 2021
Letter contrast sensitivity function of the eye
1Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia.
Purpose:
To provide empirical data of letter CSF for various levels of defocus under controlled conditions of luminance and age.
Methods:
Corrected distance visual acuities were tested at different levels of contrast and defocus. An experiment was conducted using the Medmont visual acuity tester on 10 young subjects and under normal room lighting.
Results:
Empirical data of visual acuity were obtained for 7 levels of contrast (5, 10, 15, 25, 40, 60, 80%) and defocus levels of 0, +1 and +2D. A mathematical model was derived (R2=0.995) and this can be used to estimate visual acuity at various contrast levels for defocus of < or =+2D.
Conclusion:
This information is useful for the clinician as normative data and for further development of optical models to predict visual performance of the eye.
Related Concept Videos
Vision
Accessory Structures of the Eye
Anatomy of the Eyeball
Focusing of Light in the Eye
Photoreceptors and Visual Pathways
Color Vision

