Documenta Ophthalmologica

, Volume 139, Issue 2, pp 161–168 | Cite as

Can VEP-based acuity estimates in one eye be improved by applying knowledge from the other eye?

  • Jessica Knötzele
  • Sven P. HeinrichEmail author
Technical Note



It is desirable to make VEP-based acuity estimates match standard subjective acuity numerically, as the latter is familiar to ophthalmologists and optometrists. This is achieved by applying an empirical conversion factor, and previous studies found the resulting values to be within ±1 octave of subjective acuity. This leaves room for improvement. In the present study, we tested for the case of a monocular acuity deficit whether the known difference between subjective and objective acuity in the trusted fellow eye can be used to get a more precise objective estimate in the eye of which the acuity is to be estimated. In other words, we tested whether it would make sense to determine a patient-specific conversion factor.


In 19 subjects, we obtained monocular objective and subjective acuity estimates with both eyes. Normal vision and artificially degraded vision were tested. Subjective acuity was taken as the veridical value. We computed the differences between objective and subjective acuity and reasoned that if these were correlated between eyes and acuity levels, the valid information from the trusted healthy eye could be used to improve the precision of the acuity estimate in the other, potentially impaired, eye.


The difference between objective and subjective acuity values was neither correlated significantly between eyes, nor was it correlated significantly between acuity levels.


Knowledge about the discrepancy between objective and subjective acuity values in one eye does not help improving the accuracy of acuity estimates in the other eye. The lack of a significant correlation between eyes even at the same acuity level suggests that a major part of the discrepancies between subjective acuity and VEP-based acuity is not the result of factors that would equally apply to both eyes, such as cortical morphology.


Visual evoked potential Objective visual acuity Subjective visual acuity Contralateral eye Inter-ocular correlation Stimulus calibration 



We are grateful to the study participants for their support.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Statement of human rights

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Statement on the welfare of animals

This article does not contain any studies with animals performed by any of the authors.

Informed consent

Informed consent was obtained from all individual participants included in the study.


  1. 1.
    Springer C, Bültmann S, Krastel H, Rohrschneider K (2007) Objektivierung der Sehfunktionen bei Begutachtungen. Ophthalmologe 104:474–479. CrossRefGoogle Scholar
  2. 2.
    Towle VL, Harter MR (1977) Objective determination of human visual acuity: pattern evoked potentials. Invest Ophthalmol Vis Sci 16:1073–1076Google Scholar
  3. 3.
    Nakamura A, Akio T, Matsuda E, Wakami Y (2001) Pattern visual evoked potentials in malingering. J Neuroophthalmol 21:42–45CrossRefGoogle Scholar
  4. 4.
    Mackay AM, Bradnam MS, Hamilton R et al (2008) Real-time rapid acuity assessment using VEPs: development and validation of the step VEP technique. Invest Ophthalmol Vis Sci 49:438–441. CrossRefGoogle Scholar
  5. 5.
    Bach M, Maurer JP, Wolf ME (2008) Visual evoked potential-based acuity assessment in normal vision, artificially degraded vision, and in patients. Br J Ophthalmol 92:396–403. CrossRefGoogle Scholar
  6. 6.
    Almoqbel F, Leat SJ, Irving E (2008) The technique, validity and clinical use of the sweep VEP. Ophthalmic Physiol Opt 28:393–403. CrossRefGoogle Scholar
  7. 7.
    Bach M (1996) The Freiburg Visual Acuity Test–automatic measurement of visual acuity. Optom Vis Sci 73:49–53CrossRefGoogle Scholar
  8. 8.
    Heinrich SP, Bock CM, Bach M (2016) Imitating the effect of amblyopia on VEP-based acuity estimates. Doc Ophthalmol 133:183–187. CrossRefGoogle Scholar
  9. 9.
    Beusterien ML, Heinrich SP (2018) P300-based acuity estimation in imitated amblyopia. Doc Ophthalmol 136:69–74. CrossRefGoogle Scholar
  10. 10.
    Strasburger H, Bach M, Heinrich SP (2018) Blur unblurred-a mini tutorial. i-Perception 9:2041669518765850. Google Scholar
  11. 11.
    Odom JV, Bach M, Brigell M et al (2016) ISCEV standard for clinical visual evoked potentials: (2016 update). Doc Ophthalmol 133:1–9. CrossRefGoogle Scholar
  12. 12.
    Wenner Y, Heinrich SP, Beisse C et al (2014) Visual evoked potential-based acuity assessment: overestimation in amblyopia. Doc Ophthalmol 128:191–200. CrossRefGoogle Scholar
  13. 13.
    Bach M, Meigen T (1999) Do’s and don’ts in Fourier analysis of steady-state potentials. Doc Ophthalmol 99:69–82CrossRefGoogle Scholar
  14. 14.
    Meigen T, Bach M (1999) On the statistical significance of electrophysiological steady-state responses. Doc Ophthalmol 98:207–232CrossRefGoogle Scholar
  15. 15.
    Strasburger H, Scheidler W, Rentschler I (1988) Amplitude and phase characteristics of the steady-state visual evoked potential. Appl Opt 27:1069–1088CrossRefGoogle Scholar
  16. 16.
    Joost W, Bach M (1990) Variability of the steady-state visually evoked potential: interindividual variance and intraindividual reproducibility of spatial frequency tuning. Doc Ophthalmol 75:59–66CrossRefGoogle Scholar
  17. 17.
    Heinrich SP (2010) Some thoughts on the interpretation of steady-state evoked potentials. Doc Ophthalmol 120:205–214. CrossRefGoogle Scholar
  18. 18.
    Heinrich SP, Bach M (2013) Resolution acuity versus recognition acuity with Landolt-style optotypes. Graefes Arch Clin Exp Ophthalmol 251:2235–2241. CrossRefGoogle Scholar
  19. 19.
    Chung STL, Legge GE (2016) Comparing the shape of contrast sensitivity functions for normal and low vision. Invest Ophthalmol Vis Sci 57:198–207. CrossRefGoogle Scholar
  20. 20.
    Paudel N, Jacobs RJ, Sloan R et al (2017) Effect of simulated refractive error on adult visual acuity for paediatric tests. Ophthalmic Physiol Opt 37:521–530. CrossRefGoogle Scholar
  21. 21.
    Heinrich SP, Krüger K, Bach M (2010) The effect of optotype presentation duration on acuity estimates revisited. Graefes Arch Clin Exp Ophthalmol 248:389–394. CrossRefGoogle Scholar
  22. 22.
    Di Russo F, Spinelli D (2002) Effects of sustained, voluntary attention on amplitude and latency of steady-state visual evoked potential: a costs and benefits analysis. Clin Neurophysiol 113:1771–1777CrossRefGoogle Scholar
  23. 23.
    Di Russo F, Spinelli D, Morrone MC (2001) Automatic gain control contrast mechanisms are modulated by attention in humans: evidence from visual evoked potentials. Vis Res 41:2435–2447CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Eye Center, Medical Center and Faculty of MedicineUniversity of FreiburgFreiburgGermany

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