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. 1997 Dec;81(12):1050–1055. doi: 10.1136/bjo.81.12.1050

Pulfrich's phenomenon in unilateral cataract

S Scotcher 1, D Laidlaw 1, C Canning 1, M Weal 1, R Harrad 1
PMCID: PMC1722100  PMID: 9497463

Abstract

AIMS—To determine whether unilateral cataract causes a pathological Pulfrich's phenomenon.
METHODS—29 subjects with unilateral cataract and contralateral pseudophakia were assessed on their ability to perceive the Pulfrich phenomenon. Using a computer generated pendulum image, and graded neutral density filters, a series of forced choice trials were performed in which the subject was required to describe the direction of any apparent pendulum rotation. A pathological Pulfrich effect was said to occur when apparent rotation was perceived in the presence of a zero strength neutral density filter. The size of any pathological Pulfrich effect which was present was quantified by neutralising the perceived pendulum rotation with neutral density filters of varying strength placed before the better seeing eye.
RESULTS—20 out of 29 subjects were able to perceive apparent pendulum rotation when uniocular filtering was performed. In the group (n=12) which was tested both before and after cataract extraction with intraocular lens implantation, a statistically significant pathological Pulfrich effect was demonstrated preoperatively, compared with a group of normal control subjects. This effect was abolished after cataract extraction (p=0.009). The median size of the effect was equivalent to a 0.25 log unit neutral density filter over the non-cataractous eye. The subjects who were unable to perceive the Pulfrich phenomenon at all had a significantly greater difference in the visual acuity of each eye (p=0.045) and significantly worse stereoacuity than those who were able to perceive the effect (p=0.002).
CONCLUSIONS—Unilateral cataract can cause a pathological Pulfrich phenomenon. This finding may explain why some patients with unilateral cataract complain of visual symptoms that are not easily accounted for in terms of visual acuity, contrast sensitivity, or stereoacuity.



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Figure 1  .

Figure 1  

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Pulfrich's phenomenon. In this example the right eye is covered by a light attenuating filter. As the pendulum swings from right to left (A), the left eye sees the pendulum at point x. At the same moment, the right eye sees the pendulum at point y. At a cortical level this disparity between the inputs from the two eyes is interpreted as a change in the apparent distance between the target and observer, and the pendulum is consequently perceived as being at point z, behind the actual plane of the swinging pendulum. When the pendulum changes direction (B), the pendulum is perceived to swing anterior to its true path.

Figure 2  .

Figure 2  

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Preoperative subjects (n=12). Perceived rotation (median total score) with 95% confidence intervals plotted against neutral filter density (log units); +ve filter value = filter over cataractous eye; −ve filter value = filter over pseudophakic eye.

Figure 3  .

Figure 3  

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Postoperative subjects (n=12). Perceived rotation (median total score) with 95% confidence intervals plotted against neutral filter density (log units). +ve filter value = filter over second operated eye, −ve filter value = filter over first operated eye.

Figure 4  .

Figure 4  

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Control subjects (n=11). Perceived rotation (median total score) with 95% confidence intervals plotted against neutral filter density (log units). +ve filter value = filter over right eye, -ve filter value = filter over left eye.

Selected References

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

  1. Collins D. W., Carroll W. M., Black J. L., Walsh M. Effect of refractive error on the visual evoked response. Br Med J. 1979 Jan 27;1(6158):231–232. doi: 10.1136/bmj.1.6158.231. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Enright J. T. Distortions of apparent velocity: a new optical illusion. Science. 1970 Apr 24;168(3930):464–467. doi: 10.1126/science.168.3930.464. [DOI] [PubMed] [Google Scholar]
  3. Frisen L., Hoyt W. F., Bird A. C., Weale R. A. Diagnostic uses of the Pulfrich phenomenon. Lancet. 1973 Aug 18;2(7825):385–386. doi: 10.1016/s0140-6736(73)93238-8. [DOI] [PubMed] [Google Scholar]
  4. Grimsdale H. A NOTE ON PULFRICH'S PHENOMENON WITH A SUGGESTION ON ITS POSSIBLE CLINICAL IMPORTANCE. Br J Ophthalmol. 1925 Feb;9(2):63–65. doi: 10.1136/bjo.9.2.63. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Heron G., Dutton G. N. The Pulfrich phenomenon and its alleviation with a neutral density filter. Br J Ophthalmol. 1989 Dec;73(12):1004–1008. doi: 10.1136/bjo.73.12.1004. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Javitt J. C., Steinberg E. P., Sharkey P., Schein O. D., Tielsch J. M., Diener M., Legro M., Sommer A. Cataract surgery in one eye or both. A billion dollar per year issue. Ophthalmology. 1995 Nov;102(11):1583–1593. doi: 10.1016/s0161-6420(95)30824-x. [DOI] [PubMed] [Google Scholar]
  7. Laidlaw A., Harrad R. Can second eye cataract extraction be justified? Eye (Lond) 1993;7(Pt 5):680–686. doi: 10.1038/eye.1993.155. [DOI] [PubMed] [Google Scholar]
  8. Landrigan D. T. Measurements of the Pulfrich effect over days of exposure. J Psychol. 1984 May;117(1ST):125–133. doi: 10.1080/00223980.1984.9923668. [DOI] [PubMed] [Google Scholar]
  9. Larkin E. B., Dutton G. N., Heron G. Impaired perception of moving objects after minor injuries to the eye and midface: the Pulfrich phenomenon. Br J Oral Maxillofac Surg. 1994 Dec;32(6):360–362. doi: 10.1016/0266-4356(94)90025-6. [DOI] [PubMed] [Google Scholar]
  10. Mansfield R. J., Daugman J. G. Retinal mechanisms of visual latency. Vision Res. 1978;18(9):1247–1260. doi: 10.1016/0042-6989(78)90111-6. [DOI] [PubMed] [Google Scholar]
  11. Pardhan S., Gilchrist J. The importance of measuring binocular contrast sensitivity in unilateral cataract. Eye (Lond) 1991;5(Pt 1):31–35. doi: 10.1038/eye.1991.6. [DOI] [PubMed] [Google Scholar]
  12. Rushton D. Use of the Pulfrich pendulum for detecting abnormal delay in the visual pathway in multiple sclerosis. Brain. 1975 Jun;98(2):283–296. doi: 10.1093/brain/98.2.283. [DOI] [PubMed] [Google Scholar]
  13. Sadun A. A., Bassi C. J., Lessell S. Why cataracts do not produce afferent pupillary defects. Am J Ophthalmol. 1990 Dec 15;110(6):712–714. doi: 10.1016/s0002-9394(14)77079-5. [DOI] [PubMed] [Google Scholar]
  14. Sadun A. A., Libondi T. Transmission of light through cataracts. Am J Ophthalmol. 1990 Dec 15;110(6):710–712. doi: 10.1016/s0002-9394(14)77078-3. [DOI] [PubMed] [Google Scholar]
  15. Sokol S., Moskowitz A. Effect of retinal blur on the peak latency of the pattern evoked potential. Vision Res. 1981;21(8):1279–1286. doi: 10.1016/0042-6989(81)90232-7. [DOI] [PubMed] [Google Scholar]
  16. Wolpert D. M., Miall R. C., Cumming B., Boniface S. J. Retinal adaptation of visual processing time delays. Vision Res. 1993 Jul;33(10):1421–1430. doi: 10.1016/0042-6989(93)90048-2. [DOI] [PubMed] [Google Scholar]
  17. Zigman S., Groff J., Yulo T., Griess G. Light extinction and protein in lens. Exp Eye Res. 1976 Nov;23(5):555–567. doi: 10.1016/0014-4835(76)90163-9. [DOI] [PubMed] [Google Scholar]

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