The colours of after-images, following strong light-stimuli

Licht- und Farbensinn

The human visual system can operate in a wide range of illumination levels due to several adaptation processes working in concert. For the most part, these adaptation mechanisms are transparent, leaving the observer unaware of his or her absolute adaptation state. At extreme illumination levels, however, some of these mechanisms produce perceivable secondary effects, or epiphenomena. In bright light, these include bleaching afterimages and adaptation afterimages, while in dark conditions these include desaturation, loss of acuity, mesopic hue shift, and the Purkinje effect. In this work we examine whether displaying these effects explicitly can be used to extend the apparent dynamic range of a conventional computer display. We present phenomenological models for each effect, describe efficient computer graphics methods for rendering our models, and propose a gaze-adaptive display that injects the effects into imagery on a standard computer monitor. Finally, we report the results of psychophysical experiments which reveal that, while mesopic epiphenomena are a strong cue that a stimulus is very dark, afterimages have little impact on the perception that a stimulus is very bright.

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Simulating the Visual Experience of Very Bright and Very Dark Scenes

A bright pocket flashlight was directed into one eye for 10 seconds; the subject then closed the eyelids and reported the sequence of after-image colours observed. Lesions of the visual system which compromised bilateral central colour vision also reduced or abolished the `flight of colours'. This simple bedside test of each eye independently is of value in detecting mild defects of central vision.

https://jnnp.bmj.com/content/jnnp/37/11/1265.full.pdf

`Flight of colours' in lesions of the visual system

Perceptual suppression of afterimages.

Conclusion The growth described is a typical endothelioma. There is some evidence suggestive of the presence of a thin layer of growtlh which lies between the dural and pial sheaths on the nasal side of the nerve and that this layer of growth, wrapped around the nerve superficial to its pial sheath, much thicker on the temporal side, has on that side grown more rapidly and spread more freely into and through the dural sheath. On the other hand, it may quite well be stated that the growth arose as an extra-dural endothelioma, or from lymph. channels in the dural sheath, and that it extended inwards into the subdural space. The neoplasm h1as extended to such dimensions that a decision as to this is impossible. However, as shown in a previous paper(2), an endothelioma arising in the endothelium of the subdural space, either superficial or deep to the arachnoid sheath, may at an early stage spread into and through, and largely destroy the arrangement of the dural sheath. Further, the subdural space is a recognized source of endothelioma of the optic nerve. It is probable, therefore, that the growth in this case originated from the endothelium of the subdural space.

https://bjo.bmj.com/content/bjophthalmol/9/12/618.full.pdf

Glaucoma secondary to choroidal sarcoma. the treatment of painful blind glaucomatous eyes

https://bjo.bmj.com/content/bjophthalmol/9/12/627.full.pdf

The colours of after-images, following strong light-stimuli

Citations

Licht- und Farbensinn

Simulating the Visual Experience of Very Bright and Very Dark Scenes

`Flight of colours' in lesions of the visual system

Perceptual suppression of afterimages.

Glaucoma secondary to choroidal sarcoma. the treatment of painful blind glaucomatous eyes

References

IV.—SOME NEW OBSERVATIONS IN SUPPORT OF THOMAS YOUNG'S THEORY OF LIGHT- AND COLOUR-VISION (III. Conclusion)