Skip to main content
NCBI home page
The British Journal of Ophthalmology logoLink to The British Journal of Ophthalmology
. 1994 Jul;78(7):572–576. doi: 10.1136/bjo.78.7.572

Definition of thresholds for stereoscopic depth.

M Fahle 1, S Henke-Fahle 1, J Harris 1
PMCID: PMC504866  PMID: 7918271

Abstract

In the laboratory, thresholds for stereoscopic depth perception are usually determined by asking observers to discriminate between a stimulus with a given depth offset and its mirror image. Threshold is most often defined as the disparity difference that yields 75% or 83% correct responses. Disparities used for clinical tests of stereopsis are much higher. Here it is argued that, among other factors, this is because of the fact that clinical tests usually require the detection of a depth difference (offset versus no offset), rather than the discrimination between two directions of depth difference (in front versus behind). From a formal comparison of the two tasks, the data show that discrimination, or classification is easier by at least a factor of 2 than detection. The contribution of variations of the threshold criterion and learning to the differences between stereoacuity as measured in laboratory and clinic is also discussed. These differences are relevant to the design of tests for clinical use.

Full text

PDF
572

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Allik J., Dzhafarov E., Rauk M. Position discrimination may be better than detection. Vision Res. 1982;22(8):1079–1081. doi: 10.1016/0042-6989(82)90047-5. [DOI] [PubMed] [Google Scholar]
  2. Ball K., Sekuler R. Direction-specific improvement in motion discrimination. Vision Res. 1987;27(6):953–965. doi: 10.1016/0042-6989(87)90011-3. [DOI] [PubMed] [Google Scholar]
  3. Bennett R. G., Westheimer G. The effect of training on visual alignment discrimination and grating resolution. Percept Psychophys. 1991 Jun;49(6):541–546. doi: 10.3758/bf03212188. [DOI] [PubMed] [Google Scholar]
  4. Fahle M., Edelman S. Long-term learning in vernier acuity: effects of stimulus orientation, range and of feedback. Vision Res. 1993 Feb;33(3):397–412. doi: 10.1016/0042-6989(93)90094-d. [DOI] [PubMed] [Google Scholar]
  5. Fahle M., Poggio T. Visual hyperacuity:spatiotemporal interpolation in human vision. Proc R Soc Lond B Biol Sci. 1981 Nov 24;213(1193):451–477. doi: 10.1098/rspb.1981.0075. [DOI] [PubMed] [Google Scholar]
  6. Fahle M., Westheimer G. Local and global factors in disparity detection of rows of points. Vision Res. 1988;28(1):171–178. [PubMed] [Google Scholar]
  7. Fendick M., Westheimer G. Effects of practice and the separation of test targets on foveal and peripheral stereoacuity. Vision Res. 1983;23(2):145–150. doi: 10.1016/0042-6989(83)90137-2. [DOI] [PubMed] [Google Scholar]
  8. Klein S. A. Double-judgment psychophysics: problems and solutions. J Opt Soc Am A. 1985 Sep;2(9):1560–1585. doi: 10.1364/josaa.2.001560. [DOI] [PubMed] [Google Scholar]
  9. Klein S. A., Levi D. M. Hyperacuity thresholds of 1 sec: theoretical predictions and empirical validation. J Opt Soc Am A. 1985 Jul;2(7):1170–1190. doi: 10.1364/josaa.2.001170. [DOI] [PubMed] [Google Scholar]
  10. Krauskopf J. Discrimination and detection of changes in luminance. Vision Res. 1980;20(8):671–677. doi: 10.1016/0042-6989(80)90091-7. [DOI] [PubMed] [Google Scholar]
  11. McKee S. P., Westheimer G. Improvement in vernier acuity with practice. Percept Psychophys. 1978 Sep;24(3):258–262. doi: 10.3758/bf03206097. [DOI] [PubMed] [Google Scholar]
  12. Morgan M. J., Watt R. J. Mechanisms of interpolation in human spatial vision. Nature. 1982 Oct 7;299(5883):553–555. doi: 10.1038/299553a0. [DOI] [PubMed] [Google Scholar]
  13. Poggio T., Fahle M., Edelman S. Fast perceptual learning in visual hyperacuity. Science. 1992 May 15;256(5059):1018–1021. doi: 10.1126/science.1589770. [DOI] [PubMed] [Google Scholar]
  14. Thomas J. P. Detection and identification: how are they related? J Opt Soc Am A. 1985 Sep;2(9):1457–1467. doi: 10.1364/josaa.2.001457. [DOI] [PubMed] [Google Scholar]
  15. Vogels R., Orban G. A. The effect of practice on the oblique effect in line orientation judgments. Vision Res. 1985;25(11):1679–1687. doi: 10.1016/0042-6989(85)90140-3. [DOI] [PubMed] [Google Scholar]
  16. Westheimer G. Diffraction theory and visual hyperacuity. Am J Optom Physiol Opt. 1976 Jul;53(7):362–364. doi: 10.1097/00006324-197607000-00006. [DOI] [PubMed] [Google Scholar]
  17. Westheimer G., McKee S. P. Stereogram design for testing local stereopsis. Invest Ophthalmol Vis Sci. 1980 Jul;19(7):802–809. [PubMed] [Google Scholar]

Articles from The British Journal of Ophthalmology are provided here courtesy of BMJ Publishing Group

RESOURCES