Abstract

The parafoveal short-wavelength-sensitivity mechanism in a protanopic patient with retinitis pigmentosa was found to lack the secondary (long-wavelength) field-sensitivity mode, a property that is characteristic of Stiles’s pi 1 mechanism. The results document that normal protanopic observers also lack this mode and reject the hypothesis that the present measurements reflect a pi 3-like—rather than the pi 1-like—mechanism.

© 1982 Optical Society of America

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References

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  1. E. N. Pugh and J. D. Mollon, “A theory of the pi 1 and pi 3 color mechanisms of Stiles,” Vision Res. 19, 293–312 (1979).
    [CrossRef]
  2. R. Young and G. Fishman, “Sensitivity losses in a long wavelength sensitive mechanism of patients with retinitis pigmentosa,” Vision Res. (to be published).
  3. R. S. Young, “Early-stage abnormality of foveal pi mechanisms in a patient with retinitis pigmentosa,” J. Opt. Soc. Am. 72, 1021–1025 (1982).
    [CrossRef] [PubMed]
  4. R. D. Watkins, “Foveal increment thresholds in protan observers,” Vision Res. 9, 1197–1204 (1969).
    [CrossRef] [PubMed]
  5. G. Wyszecki and W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulas (Wiley, New York, 1967).
  6. F. M. de Monasterio, S. J. Schein, and E. P. McCrane, “Staining of blue-sensitive cones of macaque retina by a fluorescent dye,” Invest. Ophthalmol. Vis. Sci. Suppl. 20, 151 (1981).
  7. J. D. Mollon and P. G. Polden, “An anomaly in the response of the eye to light of short wavelengths,” Phil. Trans. R. Soc. London Ser. B 278, 207–240 (1977).
    [CrossRef]

1982 (1)

1981 (1)

F. M. de Monasterio, S. J. Schein, and E. P. McCrane, “Staining of blue-sensitive cones of macaque retina by a fluorescent dye,” Invest. Ophthalmol. Vis. Sci. Suppl. 20, 151 (1981).

1979 (1)

E. N. Pugh and J. D. Mollon, “A theory of the pi 1 and pi 3 color mechanisms of Stiles,” Vision Res. 19, 293–312 (1979).
[CrossRef]

1977 (1)

J. D. Mollon and P. G. Polden, “An anomaly in the response of the eye to light of short wavelengths,” Phil. Trans. R. Soc. London Ser. B 278, 207–240 (1977).
[CrossRef]

1969 (1)

R. D. Watkins, “Foveal increment thresholds in protan observers,” Vision Res. 9, 1197–1204 (1969).
[CrossRef] [PubMed]

de Monasterio, F. M.

F. M. de Monasterio, S. J. Schein, and E. P. McCrane, “Staining of blue-sensitive cones of macaque retina by a fluorescent dye,” Invest. Ophthalmol. Vis. Sci. Suppl. 20, 151 (1981).

Fishman, G.

R. Young and G. Fishman, “Sensitivity losses in a long wavelength sensitive mechanism of patients with retinitis pigmentosa,” Vision Res. (to be published).

McCrane, E. P.

F. M. de Monasterio, S. J. Schein, and E. P. McCrane, “Staining of blue-sensitive cones of macaque retina by a fluorescent dye,” Invest. Ophthalmol. Vis. Sci. Suppl. 20, 151 (1981).

Mollon, J. D.

E. N. Pugh and J. D. Mollon, “A theory of the pi 1 and pi 3 color mechanisms of Stiles,” Vision Res. 19, 293–312 (1979).
[CrossRef]

J. D. Mollon and P. G. Polden, “An anomaly in the response of the eye to light of short wavelengths,” Phil. Trans. R. Soc. London Ser. B 278, 207–240 (1977).
[CrossRef]

Polden, P. G.

J. D. Mollon and P. G. Polden, “An anomaly in the response of the eye to light of short wavelengths,” Phil. Trans. R. Soc. London Ser. B 278, 207–240 (1977).
[CrossRef]

Pugh, E. N.

E. N. Pugh and J. D. Mollon, “A theory of the pi 1 and pi 3 color mechanisms of Stiles,” Vision Res. 19, 293–312 (1979).
[CrossRef]

Schein, S. J.

F. M. de Monasterio, S. J. Schein, and E. P. McCrane, “Staining of blue-sensitive cones of macaque retina by a fluorescent dye,” Invest. Ophthalmol. Vis. Sci. Suppl. 20, 151 (1981).

Stiles, W. S.

G. Wyszecki and W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulas (Wiley, New York, 1967).

Watkins, R. D.

R. D. Watkins, “Foveal increment thresholds in protan observers,” Vision Res. 9, 1197–1204 (1969).
[CrossRef] [PubMed]

Wyszecki, G.

G. Wyszecki and W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulas (Wiley, New York, 1967).

Young, R.

R. Young and G. Fishman, “Sensitivity losses in a long wavelength sensitive mechanism of patients with retinitis pigmentosa,” Vision Res. (to be published).

Young, R. S.

Invest. Ophthalmol. Vis. Sci. Suppl. (1)

F. M. de Monasterio, S. J. Schein, and E. P. McCrane, “Staining of blue-sensitive cones of macaque retina by a fluorescent dye,” Invest. Ophthalmol. Vis. Sci. Suppl. 20, 151 (1981).

J. Opt. Soc. Am. (1)

Phil. Trans. R. Soc. London Ser. B (1)

J. D. Mollon and P. G. Polden, “An anomaly in the response of the eye to light of short wavelengths,” Phil. Trans. R. Soc. London Ser. B 278, 207–240 (1977).
[CrossRef]

Vision Res. (2)

R. D. Watkins, “Foveal increment thresholds in protan observers,” Vision Res. 9, 1197–1204 (1969).
[CrossRef] [PubMed]

E. N. Pugh and J. D. Mollon, “A theory of the pi 1 and pi 3 color mechanisms of Stiles,” Vision Res. 19, 293–312 (1979).
[CrossRef]

Other (2)

R. Young and G. Fishman, “Sensitivity losses in a long wavelength sensitive mechanism of patients with retinitis pigmentosa,” Vision Res. (to be published).

G. Wyszecki and W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulas (Wiley, New York, 1967).

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Figures (5)

Fig. 1
Fig. 1

Field sensitivity of a short-wavelength mechanism (4° temporal retina) in a protanopic patient with retinitis pigmentosa. Test was a 430-nm flash (1° diameter, 200-msec duration); auxiliary field was 550 nm (8.5° diameter) presented steadily either at 9.1 log quanta/sec/deg2 (triangles) or at 10 log quanta/sec/deg2 (diamonds). Data (diamonds) were displaced upward by 0.48 log sensitivity to illustrate the similarity between the two experiments. Solid curve is a sws cone action spectrum derived from test- and field-sensitivity data of two blue-cone monochromats.

Fig. 2
Fig. 2

Preliminary experiment illustrating the method used to measure the field sensitivity of the short-wavelength-sensitivity mechanism. Left-hand side, the parafoveal increment-threshold function of a representative normal protanope (CL). The first branch of the curve (B1) is mediated by rods. The second branch (B2) is probably mediated by a mws mechanism, as described in the text. The vertical arrow indicates the 550-nm auxiliary field flux chosen to isolate the third branch (B3). Right-hand side, typical increment-threshold functions generated by adding main fields of varying flux to the 550-nm auxiliary field. The ordinate presents the relative main field fluxes. The wavelengths (nm) are designated by μ2, and the respective field-sensitivity values (quanta−1 sec deg2) by Π(μ2).

Fig. 3
Fig. 3

Field-sensitivity spectra measured in the foveae and parafoveae (4° temporal retina) of normal protan observers. Top panel, foveal spectrum shows the expected secondary mode (dotted curve) that has been found in normal trichromatic observers. Observer EL is a protanope, and DD is an extreme protanomal. Bottom panel, the secondary mode is not apparent in the parafoveae of protanopic observers (CL and GR). Solid line is based on the test- and field-sensitivity spectra of the short-wavelength-sensitive mechanism in two blue-cone monochromats tested on the same instrument.

Fig. 4
Fig. 4

Increment-threshold evidence that the B2 branch behaves relatively independently of the B3 branch. Test wavelength is 430 nm. (a) Same increment-threshold data as in Fig. 2. The solid curve, however, illustrates our inference that the B2 increment threshold actually continues beyond the emergence of the B3 branch. The inference is based on the extrapolated minimum thresholds for the upper branch in each of the functions in (b)–(d). (b)–(d) Increment-threshold function for a 430-nm test flash on 430-nm main field mixed with a 550-nm auxiliary field of (b) 7.97 log quanta/sec/deg2, (c) 8.37 log quanta/sec/deg2, and (d) 8.77 log quanta/sec/deg2. The template curve through the lower branches was positioned identically in each panel in accordance with the assumption that the data are mediated by the B3 mechanism. The template curve through the upper branch was slid along a 45° line (dashes) that the data appeared to converge toward. The resultant fit of the template curve to the data provides an estimate of the minimum threshold for the different auxiliary field fluxes in accordance with the hypothesis that the upper branches are mediated by the B2 mechanism.

Fig. 5
Fig. 5

Parafoveal color matches of the protanopic patient with retinitis pigmentosa. The bistimulus values are comparable with average values derived in the foveae of protanopes.5 Stimulus is 5° bipartite field viewed about 4° from the fovea.