Accommodative microfluctuations: a mechanism for steady-state control of accommodation

  • Barry Winn
Conference paper

Summary

Rapid and continuous fluctuations in ocular focus are known to occur when the eye views a stationary stimulus. The advent of high-speed infra-red optometers has established that these microfluctuations of ocular accommodation have two dominant components: a low frequency component (LFC) of <0.6Hz and a high frequency component (HFC) between 1.0 and 2.3Hz. Although the retinal image blur associated with microfluctuations has the potential to guide and maintain optimum accommodation levels, there is no consensus with regard to the respective contribution of each of the dominant frequency components. In an attempt to clarify the role of the accommodation microfluctuations we have conducted a series of experiments to investigate their nature and aetiology. Manipulation of stimulus parameters and viewing conditions along with the use of topical drugs has allowed induced changes in the response waveform to be investigated.

A significant between-subject variation in the HFC was found and led us to consider the relationship between this component and other physiological mechanisms which provide intraocular rhythmic variation. Simultaneous measurements of ocular accommodation and systemic arterial pulse frequency demonstrate that the location of the HFC is significantly correlated with arterial pulse frequency. We have also identified a relationship between the power in the LFC and the quality of the retinal image. However, the failure of the HFC to vary with stimulus conditions in a consistent manner supports the result that it is associated with accommodative plant noise rather than being under neurological control. There is an increased requirement for low-frequency modulation of retinal image contrast when the feedback system is placed under duress suggesting that the LFCs play a role in the control of sustained accommodation. The studies to date suggest that the complex waveform of the accommodative microfluctuations is a consequence of the combination of neurological control and physiological rhythmic variation: the former attributable to the LFCs; the latter to arterial pulse.

Keywords

Retinal Image High Frequency Component Pupil Size Pupil Diameter Arterial Pulse 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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References

  1. Alpern, M. (1958) Variability of accommodation during steady fixation at various levels of illuminance. Journal of the Optical Society of America 48: 193–197.PubMedCrossRefGoogle Scholar
  2. Arnulf, A., Dupuy, O. and Flamant, F. (1951a) Les microfluctuations d’accommodation de l’oeil et l’acuité visuelle pour les diamétres pupillaires naturelles. Comptes Rendus de la Academie des Science, Paris, 232: 339–341.Google Scholar
  3. Arnulf, A., Dupuy, O. and Flamant, F. (1951b) Les microfluctuations de l’oeil et leur influence sur l’image rétiniene. Comptes Rendus Hebdomadaire de l’Académie des Sciences, Paris, 232: 438–450.Google Scholar
  4. Berny, F. (1969) Etude de la formation des images rétiniennes et determination de l’aberration de sphericité de l’oeil human. Vision Research, 9: 977–990.PubMedCrossRefGoogle Scholar
  5. Berny, F. and Slansky, S. (1970) Wavefront determination resulting from Foucault test as applied to the human eye and visual instruments. In J. Home (ed.): Optical instruments and techniques, Oriel, Newcastle-upon-Tyne, pp. 375–386.Google Scholar
  6. Campbell, F.W. and Robson, J.G. (1959) High-speed infra-red optometer. Journal of the Optical Society of America, 49: 268–272.PubMedCrossRefGoogle Scholar
  7. Campbell, F.W., Robson, J.G. and Westheimer, G. (1959) Fluctuations of accommodation under steady viewing conditions. Journal of Physiology, 145: 579–594.PubMedGoogle Scholar
  8. Campbell, F.W., Westheimer, G. and Robson, J.G. (1959) Significance of fluctuations of accommodation Journal of the Optical Society of America, 48: 669.CrossRefGoogle Scholar
  9. Charman, W.N. (1983) The retinal image in the human eye. In N. Osborne and G. Chader (eds.): Progress in Retinal Research, Vol. 2, Pergamon, Oxford pp. 1–50.Google Scholar
  10. Charman, W.N. and Heron, G. (1988) Fluctuations in accommodation: a review. Ophthalmic and Physiological Optics, 8: 153–164.PubMedCrossRefGoogle Scholar
  11. Collins, G. (1937) The electronic refractometer. British Journal of Physiological Optics, 1: 30–40.Google Scholar
  12. Collins, M., Davis, B. and Wood, J. (1995) Microfluctuations of steady-state accommodation and the cardiopulmonary system. Vision Research, 35: 2491–2502.PubMedGoogle Scholar
  13. Crane, H.D. (1966) A theoretical analysis of the visual accommodation system in humans. Report NASA CR-606, NASA, Washington.Google Scholar
  14. Denieul, P. (1982) Effects of stimulus vergence on near accommodation response, microfluctuations and accommodation and optical quality of the human eye. Vision Research, 23: 561–569.CrossRefGoogle Scholar
  15. Denieul, P. and Corno, F. (1986) Accommodation et contraste. L’optometrie, 32: 4–8.Google Scholar
  16. Gray, L.S., Winn, B. and Gilmartin, B. (1993a) Accommodative microfluctuations and pupil diameter. Vision Research, 33: 2083–2090.PubMedCrossRefGoogle Scholar
  17. Gray, L.S., Winn, B. and Gilmartin, B. (1993b) Effect of target luminance on microfluctuations of accommodation. Ophthalmic and Physiologica Optics, 13: 258–265.CrossRefGoogle Scholar
  18. Heath, G.G. (1956) The influence of visual acuity on accommodative responses of the eye. American Journal of Optometry Archives of American Academy of Optometry, 33: 513–524.CrossRefGoogle Scholar
  19. Johnson, C.A. (1976) Effects of luminance and stimulus distance on accommodation and visual resolution. Journal of the Optical Society of America, 66: 138–142.PubMedCrossRefGoogle Scholar
  20. Kotulak, J.C. and Schor, C.M. (1986a) Temporal variations in accommodation during steady-state conditions. Journal of the Optical Society of America. A, 3: 223–227.CrossRefGoogle Scholar
  21. Kotulak, J.C. and Schor, C.M. (1986b) A computational model of the error detector of human visual accommodation. Biological Cybernetics, 54: 189–194.PubMedCrossRefGoogle Scholar
  22. Owens, H., Winn, B., Gilmartin, B. and Pugh, J.R. (1991) Effect of a topical beta-adrenergic receptor antagonist on the dynamics of steady-state accommodation. Ophthalmic and Physiological Optics, 11: 99–104.PubMedCrossRefGoogle Scholar
  23. Pugh, J.R. and Winn, B. (1988) Modification of the Canon Autoref R1 for use as a continuously recording optometer. Ophthalmic and Physiological Optics, 9: 451–454.Google Scholar
  24. Westheimer, G. (1957) Accommodation measurements in empty visual fields. Journal of the Optical Society of America., 47: 714–718.PubMedCrossRefGoogle Scholar
  25. Winn, B., Pugh, J.R., Gilmartin, B. and Owens, H. (1989) The effect of pupil size on static and dynamic measurements of accommodation using an infra-red optometer. Ophthalmic and Physiological Optics, 9: 277–283.PubMedCrossRefGoogle Scholar
  26. Winn, B., Pugh, J.R., Gilmartin, B. and Owens, H. (1990a) The frequency characteristics of accommodative microfluctuations for central and peripheral zones of the human crystalline lens. Vision Research, 30: 1093–1099.PubMedCrossRefGoogle Scholar
  27. Winn, B., Pugh, J.R., Gilmartin, B. and Owens, H. (1990b) Arterial pulse modulates steady-state ocular accommodation. Current Eye Research, 9: 971–975.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Basel AG 2000

Authors and Affiliations

  • Barry Winn
    • 1
  1. 1.Department of OptometryUniversity of BradfordBradford, West YorkshireEngland

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