Abstract

A new bidirectional laser Doppler velocimeter (LDV) is described for absolute measurement of the speed of red blood cells flowing in individual retinal vessels. The basic component of the instrument is a standard retinal camera that eliminates the need for a contact lens. The laser beam is delivered to the eye through the fundus illumination optical system of the camera. Target fixation is done with the eye under examination. The measurements are independent from the ocular refraction; only the axial length of the eye need be determined. The instrument markedly simplifies the technique of retinal blood flow measurement.

© 1981 Optical Society of America

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References

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  1. C. E. Riva, G. T. Feke, B. Eberli, V. Benary, Appl. Opt. 18, 2301 (1979).
    [CrossRef] [PubMed]
  2. C. E. Riva, I. Ben-Sira, J. Opt. Soc. Am. 63, 1050 (1973).
    [CrossRef] [PubMed]
  3. Topcon retinal camera model TRC-FE, TRC-FET instruction manual.
  4. C. E. Riva, I. Ben-Sira, Appl. Opt. 14, 2691 (1975).
    [CrossRef] [PubMed]
  5. M. Katz, in Clinical Ophthalmology, Vol. 1, T. D. Duane, Ed. (Harper & Row, Hagerstown, Md., 1979), Chap. 33.
  6. C. E. Riva, B. Ross, G. B. Benedek, Invest. Ophthalmol. 11, 936 (1972).
    [PubMed]
  7. C. E. Riva, G. T. Feke, in Current Laser Technology in Medicine and Surgery, L. Goldman, Ed. (Springer, New York, 1981), Chap. 5.
  8. C. J. Bulpitt, E. M. Kohner, C. T. Dollery, Bibl. Anat. 11, 448 (1973).

1979 (1)

1975 (1)

1973 (2)

C. E. Riva, I. Ben-Sira, J. Opt. Soc. Am. 63, 1050 (1973).
[CrossRef] [PubMed]

C. J. Bulpitt, E. M. Kohner, C. T. Dollery, Bibl. Anat. 11, 448 (1973).

1972 (1)

C. E. Riva, B. Ross, G. B. Benedek, Invest. Ophthalmol. 11, 936 (1972).
[PubMed]

Benary, V.

Benedek, G. B.

C. E. Riva, B. Ross, G. B. Benedek, Invest. Ophthalmol. 11, 936 (1972).
[PubMed]

Ben-Sira, I.

Bulpitt, C. J.

C. J. Bulpitt, E. M. Kohner, C. T. Dollery, Bibl. Anat. 11, 448 (1973).

Dollery, C. T.

C. J. Bulpitt, E. M. Kohner, C. T. Dollery, Bibl. Anat. 11, 448 (1973).

Eberli, B.

Feke, G. T.

C. E. Riva, G. T. Feke, B. Eberli, V. Benary, Appl. Opt. 18, 2301 (1979).
[CrossRef] [PubMed]

C. E. Riva, G. T. Feke, in Current Laser Technology in Medicine and Surgery, L. Goldman, Ed. (Springer, New York, 1981), Chap. 5.

Katz, M.

M. Katz, in Clinical Ophthalmology, Vol. 1, T. D. Duane, Ed. (Harper & Row, Hagerstown, Md., 1979), Chap. 33.

Kohner, E. M.

C. J. Bulpitt, E. M. Kohner, C. T. Dollery, Bibl. Anat. 11, 448 (1973).

Riva, C. E.

C. E. Riva, G. T. Feke, B. Eberli, V. Benary, Appl. Opt. 18, 2301 (1979).
[CrossRef] [PubMed]

C. E. Riva, I. Ben-Sira, Appl. Opt. 14, 2691 (1975).
[CrossRef] [PubMed]

C. E. Riva, I. Ben-Sira, J. Opt. Soc. Am. 63, 1050 (1973).
[CrossRef] [PubMed]

C. E. Riva, B. Ross, G. B. Benedek, Invest. Ophthalmol. 11, 936 (1972).
[PubMed]

C. E. Riva, G. T. Feke, in Current Laser Technology in Medicine and Surgery, L. Goldman, Ed. (Springer, New York, 1981), Chap. 5.

Ross, B.

C. E. Riva, B. Ross, G. B. Benedek, Invest. Ophthalmol. 11, 936 (1972).
[PubMed]

Appl. Opt. (2)

Bibl. Anat. (1)

C. J. Bulpitt, E. M. Kohner, C. T. Dollery, Bibl. Anat. 11, 448 (1973).

Invest. Ophthalmol. (1)

C. E. Riva, B. Ross, G. B. Benedek, Invest. Ophthalmol. 11, 936 (1972).
[PubMed]

J. Opt. Soc. Am. (1)

Other (3)

Topcon retinal camera model TRC-FE, TRC-FET instruction manual.

M. Katz, in Clinical Ophthalmology, Vol. 1, T. D. Duane, Ed. (Harper & Row, Hagerstown, Md., 1979), Chap. 33.

C. E. Riva, G. T. Feke, in Current Laser Technology in Medicine and Surgery, L. Goldman, Ed. (Springer, New York, 1981), Chap. 5.

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Figures (6)

Fig. 1
Fig. 1

Schematic diagram of the optical system of the Topeon retinal camera, model TRC-FE. The components are described in the text.

Fig. 2
Fig. 2

Schematic diagram of the fundus camera based retinal LDV. The components are described in the text.

Fig. 3
Fig. 3

Gullstrand’s schematic eye. H1 and H2 are the first and second principal planes, respectively. F is the second focal point, and e the distance from the vertex of the cornea to F. A1 and A2 are virtual images of a1 and a2.

Fig. 4
Fig. 4

Position and direction of the incident laser beam at the cornea to insure that f1max and f2max are of the same sign. Both cutoff frequencies are of the same sign if the incident beam, denoted by vector Ki, enters the eye on the same side of the eye as the site of measurement (see left side of the figure). In the scattering geometry drawn on the right side, the laser beam enters on the temporal side of the eye and the site of measurement is in the nasal side. The direction of zero Doppler shift is between K1 and K2. In this case, f1max and f2max are of a different sign.

Fig. 5
Fig. 5

DSFS obtained simultaneously for two directions of the scattered light from a suspension of polysterene spheres in water flowing through a 200-μm internal diam glass capillary tube. The tube was mounted in the focal plane of a model eye (Topcon).

Fig. 6
Fig. 6

DSFS recorded simultaneously for two directions of the scattered light from a retinal artery of a human subject. The horizontal axis is the frequency of the Doppler shift. The recordings were obtained in 11 msec during minimum diastole. The positions of f1max and f2max (arrows) were determined by visual inspection of the spectra. The actual Δf is 4 times the difference between f2max and f1max because the spectral analysis was done with the FM tape moving at one-quarter the record speed.

Equations (5)

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V max = λ Δ f n Δ α cos β ,
Δ α = tan - 1 ( l f ( f - h 1 ) ( e + b - h 2 ) ) .
Δ α = tan - 1 ( 0.242 d f ( f - h 1 ) ( e + b - h 2 ) ) .
Δ α tan - 1 ( 0.257 d e ) 0.257 d e .
V max = 3.89 λ e Δ f n d cos β .

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