Documenta Ophthalmologica

, Volume 121, Issue 1, pp 1–7 | Cite as

Influence of pupil size and other test variables on visual function assessment using visual evoked potentials in normal subjects

  • Sarwat Salim
  • Kevin Childers
  • Alvaro P. C. Lupinacci
  • George Z. Hu
  • Vance Zemon
  • Peter A. Netland
Original research article

Abstract

The purpose of this study was to assess the influence of pupil size and optical blur on measurements obtained with isolated-check visual evoked potential (icVEP). Two stimulus conditions of icVEP, +15 and −15% contrasts, were studied in normal subjects with normal (N), miotic (M), and dilated (D) pupils. The effects of optical blur were studied in subjects with normal pupil. Response to visual stimuli was quantified by a signal-to-noise (SNR) ratio. In 30 normal subjects, the mean age was 26.0 ± 3.4 years. Mean pupil diameters were N = 4.2 ± 0.6 mm, M = 2.7 ± 0.6 mm, and D = 7.3 ± 0.9 mm. For both +15 and −15% contrast levels, mean SNR values were reduced for dilated and constricted pupils when compared with normal pupils. Mean SNR values for optical blur with a +2 or +3 diopter lens placed over the distance correction were reduced when compared with SNR measurements obtained with best-corrected visual acuity under both +15 and −15% contrast levels. Statistical significance was found in comparisons of N versus M (P < 0.001) and N versus D (P = 0.002) for +15 and −15% contrast conditions, respectively. No statistical difference was seen for M versus D (P = −0.435). The effect of optical blur was statistically significant when compared to the normal pupils with best-corrected vision (P < 0.001). No statistically significant difference was found comparing +2 and +3 diopters lenses for optical blur testing. Visual evoked potential values are influenced by pupillary constriction and dilation, as well as optical blur. When obtaining icVEP measurements, the influence of pupil size and optical blur should be kept in mind for accurate interpretations.

Keywords

Pupil size Visual evoked potentials Perimetry Magnocellular pathway 

References

  1. 1.
    Delgado MF, Nguyen NTA, Cox TA, Singh K, Lee DA, Dueker DK, Fechtner RD, Juzych MS, Lin SC, Netland PA, Pastor SA, Schuman JS, Samples JR, American Academy of Ophthalmology, Ophthalmic Technology Assessment Committee 2001–2002 Glaucoma Panel (2002) Automated perimetry. A report by the American academy of ophthalmology. Ophthalmology 109:2362–2374CrossRefPubMedGoogle Scholar
  2. 2.
    Klistorner A, Graham SL (2000) Objective perimetry in glaucoma. Ophthalmology 107:2283–2299CrossRefPubMedGoogle Scholar
  3. 3.
    Frankhauser F, Enoch JM (1962) The effects of blur upon perimetric thresholds. Arch Ophthalmol 68:240–251Google Scholar
  4. 4.
    Martin DD, Vonthein R, Wilhelm H, Schjiefer U (2005) Pupil size and perimetry-a pharmacological model using increment and decrement stimuli. Graefe’s Arch Clin Exp Ophthalmol 243:1091–1097CrossRefGoogle Scholar
  5. 5.
    Kerrigan-Baumrind LA, Quigley HA, Pease ME, Kerrigan DF, Mitchell RS (2000) Number of ganglion cells in glaucomatous eyes compared with threshold visual field tests in the same persons. Invest Ophthalmol Vis Sci 41:741–748PubMedGoogle Scholar
  6. 6.
    Quigley HA, Dunkelberger GR, Green WR (1988) Chronic human glaucoma causing selectively greater loss of large optic nerve fibers. Ophthalmology 95:357–363PubMedGoogle Scholar
  7. 7.
    Johnson CA, Adams AJ, Casson EJ, Brandt JD (1993) Progression of early glaucomatous visual field loss for blue-on-yellow and standard white-on-white automated perimetry. Arch Ophthalmol 111:651–656PubMedGoogle Scholar
  8. 8.
    Johnson CA, Adams AJ (1993) Blue-on-yellow perimetry can predict the development of glaucomatous visual field loss. Arch Ophthalmol 111:645–650PubMedGoogle Scholar
  9. 9.
    Johnson CA, Samuels SJ (1997) Screening for glaucomatous visual field loss with frequency- doubling perimetry. Invest Ophthalmol Vis Sci 38:413–425PubMedGoogle Scholar
  10. 10.
    Glovinsky Y, Quigley HA, Dunkelberger GR (1991) Retinal ganglion cell loss is size dependent in experimental glaucoma. Invest Ophthalmol Vis Sci 32:484–491PubMedGoogle Scholar
  11. 11.
    Zemon V, Tsai JC, Forbes M, Al-Aswad LA, Chen CM, Gordon J, Greenstein VC, Hu G, Strugstad EC, Dhrami-Gavazi E, Jindra LF (2008) Novel electrophysiological instrument for rapid and objective assessment of magnocellular deficits associated with glaucoma. Doc Ophthalmol 117:233–243CrossRefPubMedGoogle Scholar
  12. 12.
    Schiller PH, Sandell JH, Maunsell JHR (1986) Functions of the ON and OFF channels of the visual system. Nature 322:824–825CrossRefPubMedGoogle Scholar
  13. 13.
    Zemon V, Gordon J (2006) Luminance–contrast mechanisms in humans: visual evoked potentials and a nonlinear model. Vision Res 46:4163–4180CrossRefPubMedGoogle Scholar
  14. 14.
    Greenstein VC, Seliger S, Zemon V, Ritch R (1998) Visual evoked potential assessment of the effects of glaucoma on visual subsystems. Vision Res 38:1901–1911CrossRefPubMedGoogle Scholar
  15. 15.
    Jasper HH (1958) The 10–20 electrode system of the international federation. Electroencephalogr Clin Neurophysiol 10:371–375Google Scholar
  16. 16.
    Mast J, Victor JD (1991) Fluctuations of steady-state VEPs: interaction of driven evoked potentials and the EEG. Electroencephalogr Clin Neurophysiol 78:389–401CrossRefPubMedGoogle Scholar
  17. 17.
    Hood DC, Greenstein VC (2003) Multifocal VEP and ganglion cell damage: applications and limitations for the study of glaucoma. Progr Ret Eye Res 22:201–251CrossRefGoogle Scholar
  18. 18.
    Hood DC, Thienprasiddhi P, Greenstein VC, Winn BJ, Ohri N, Liebmann JM, Ritch R (2004) Detecting early to mild glaucomatous damage: a comparison of the multifocal VEP and automated perimetry. Invest Ophthalmol Vis Sci 45:492–498CrossRefPubMedGoogle Scholar
  19. 19.
    Forbes M (1966) Influence of miotics on visual fields in glaucoma. Invest Ophthalmol Vis Sci 5:139–145Google Scholar
  20. 20.
    Kee CW, Youn DH (1987) The influence of miotics on the visual field. Kor J Ophthalmol 1:52–58Google Scholar
  21. 21.
    Jay BS (1962) The effective pupillary area at varying perimetric angles. Vision Res 1:12–131CrossRefGoogle Scholar
  22. 22.
    Lindenmuth KA, Skuta GL, Rabbani R, Musch DC, Bergstrom TJ (1990) Effects of pupillary dilation on automated perimetry in normal patients. Ophthalmology 97:367–370PubMedGoogle Scholar
  23. 23.
    Mendivil A (1997) Influence of a dilated pupil on the visual field in glaucoma. J Glaucoma 6:217–220PubMedGoogle Scholar
  24. 24.
    Sokol S, Moskowitz A (1981) Effect of retinal blur on the peak latency of the pattern evoked potential. Vision Res 21:1279–1286CrossRefPubMedGoogle Scholar
  25. 25.
    Martins A, Balachandran C, Klistorner AI, Graham SL, Billson FA (2003) Effect of pupil size on multifocal pattern visual evoked potentials. Clin Exp Ophthalmol 31:354–356CrossRefGoogle Scholar
  26. 26.
    Muller W, Kollert A, Zachert C (1988) Pupil size and the steady-state pattern reversal visual evoked cortical potential. Doc Ophthalmol 68:357–361CrossRefPubMedGoogle Scholar
  27. 27.
    Hood DC, Greenstein VC, Odel JG, Zhang X, Ritch R, Liebmann JM, Hong JE, Chen CS, Thienprasiddhi P (2002) Visual field defects and multifocal visual evoked potentials: evidence of a linear relationship. Arch Ophthalmol 120:1672–1681PubMedGoogle Scholar
  28. 28.
    Graham SL, Klistorner AI, Goldberg I (2008) Clinical application of objective perimetry using multifocal visual evoked potentials in glaucoma practice. Arch Ophthalmol 123:729–739CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Sarwat Salim
    • 1
  • Kevin Childers
    • 1
  • Alvaro P. C. Lupinacci
    • 1
  • George Z. Hu
    • 2
  • Vance Zemon
    • 3
  • Peter A. Netland
    • 4
  1. 1.Department of OphthalmologyUniversity of Tennessee Health Science CenterMemphisUSA
  2. 2.SynaBridge CorpRaritanUSA
  3. 3.Albert Einstein College of MedicineYeshiva UniversityBronxUSA
  4. 4.Department of OphthalmologyUniversity of Virginia School of MedicineCharlottesvilleUSA

Personalised recommendations