The Enigma of Typical Total Monochromacy*

Alpern, Mathew; Falls, Harold F.; Lee, Gilbert B.

doi:10.1016/0002-9394(60)90353-6

Cited by 73 publications

(41 citation statements)

References 32 publications

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“…His luminous efficiency curve (peak -510 nm) was characteristic of rhodopsin absorption modified by a modest amount of macular screening pigment xanthophyll (20). This is similar to the findings in both BCM (17) and RM (19).…”

Section: Methodssupporting

confidence: 79%

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Chromosomal rearrangement segregating with adrenoleukodystrophy: associated changes in color vision.

Alpern

Sack²,

Krantz

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

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A patient from a large kindred with adrenoleukodystrophy showed profound disturbance of color ordering, color matching, increment thresholds, and luminosity. Except for color matching, his performance was similar to blue-cone "monochromacy," an X chromosome-linked recessive retinal dystrophy in which color vision is dichromatic, mediated by the visual pigments of rods and short-wavesensitive cones. Color matching, however, indicated that an abnormal rudimentary visual pigment was also present. This may reflect the presence of a recombinant visual pigment protein or altered regulation of residual pigment genes, due to DNA changes-deletion of the long-wave pigment gene and reorganized sequences 5' to the pigment gene cluster-that segregate with the metabolic defect in this kindred.

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Section: Methodssupporting

confidence: 79%

“…These measurements assess the radiance of monochromatic lights required for equal brightness, through brightness matching for successive pairs of nearby wavelengths that differ only slightly in color (10,19). Eight spectral traverses were completed by II-3.…”

Section: Methodsmentioning

confidence: 99%

Chromosomal rearrangement segregating with adrenoleukodystrophy: associated changes in color vision.

Alpern

Sack²,

Krantz

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

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“…In this paper, we report dark-adaptation curves. The peripheral curves were measured with a conventional dark adaptometer (Alpern, Falls & Lee, 1960) with the pupil of the tested eye dilated with 1 % tropicamide. It is conceivable that a curve of this kind would result from an abnormality in the optic radiations, or elsewhere in the visual central nervous system, or even perhaps from hysteria or very clever malingering.…”

Section: Methodsmentioning

confidence: 99%

Rhodopsin bleaching signals in essential night blindness

Alpern¹,

Holland²,

Ohba³

1972

The Journal of Physiology

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SUMMARY1. The dark-adaptation curves of two subjects with essential night blindness revealed no evidence for functioning rod vision. Cone vision was normal.2. The photopupillomotor dark adaptation, and flash intensity response amplitude curves on one of these subjects confirmed the absence of rod function.3. However, there is the normal amount of rhodopsin in their rods with normal kinetics.4. Cone pigment kinetics are also nearly normal. After a full bleach, log threshold elevation of the foveal cones is linearly related to pigment regeneration. The constant of proportionality is about 3-0 as it is in the normal retina.5. After a full rhodopsin bleach, the contralateral pupil size recovered its full dark value along a curve which followed the regeneration of rhodopsin.6. The results in (5) are identical to those previously found on normal subjects.7. With the exception of a very small response attributed to the contribution of cones, no significant changes in pupil size were evoked by uniform ganzfeld steady backgrounds until the intensity of retinal illuminance was so high that appreciable rhodopsin was bleached. This contrast to the changes evoked by weak steady backgrounds in the normal eye.8. Therefore, rod bleaching signals are normal in such retinas but rod signals evoked by real lights are not functional. This supports Rushton's

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“…Although each of these studies leaves much to be desired by today's standards, the evidence is overwhelming in support of the presence of at least some cone receptors in the achromat's retina. Subsequent psychophysical assessments of visual function in the achromat has exclusively concentrated on the more receptoral aspects of visual function, such as dark adaptation following bleaching lights (Sloan, 1954;XWalls & Heath, 1954;Alpern, Falls & Lee, 1960), spectral sensitivity (Sloan, achromat offers a unique opportunity to study in detail the spatial and temporal sensitivity and underlying spatial and temporal mechanisms subserving rod vision over its entire operating range. Such information is difficult to obtain in normals especially under high mesopic conditions because of interference from the more sensitive cone-driven system.…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal limits of vision in the achromat.

Hess¹,

Nordby²

1986

The Journal of Physiology

107

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SUMMARY1. Threshold detection for sine-wave grating stimuli of varying spatial and temporal frequency was used to investigate the nature of spatial and temporal post-receptoral sensitivity in the typical, complete achromat.2. Threshold spatial and temporal sensitivities under low photopic conditions show no evidence of cone function. The abrupt fall-off in sensitivity is consistent with known psychophysical and electrophysiological measures of rod saturation.3. Threshold spatial and temporal sensitivities under scotopic conditions are identical in form and absolute sensitivity to that of the normal scotopic system. 4. Spatial and temporal acuity measurements substantiate the above conclusions based on contrast sensitivity.5. We conclude that the typical and complete achromat possesses only a normal functioning rod post-receptoral mechanism.

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The Enigma of Typical Total Monochromacy*

Cited by 73 publications

References 32 publications

Chromosomal rearrangement segregating with adrenoleukodystrophy: associated changes in color vision.

Chromosomal rearrangement segregating with adrenoleukodystrophy: associated changes in color vision.

Rhodopsin bleaching signals in essential night blindness

Spatial and temporal limits of vision in the achromat.

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