Threshold measurements on the light reflex of the pupil in the dark adapted eye

Schweitzer, N.M.J.

doi:10.1007/bf00172098

Cited by 32 publications

(17 citation statements)

References 27 publications

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“…At very dim light levels it was found that for steady-state conditions (Part II) a more scotopic curve could be obtained, and Schweitzer (1956) obtained a similar result by measuring the minimum amount of light required for the smallest detectable iris change in the dark-adapted eye. The pupillometer used in the present study would not have detected this kind of a change in a fully dilated pupil without introducing artifacts due to eye movement.…”

Section: Part III Scotopic Responsesupporting

confidence: 54%

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The spectral sensitivity of the consensual light reflex

Alpern¹,

Campbell²

1962

The Journal of Physiology

114

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Although it is well known that light falling on the human retina will reduce the size of the pupil of each eye, it still cannot be unequivocally stated that this effect is obtained by the excitation of only cones, only rods, or both rods and cones. Since the spectral sensitivities of the photopic and scotopic eye are well established the identification of the photoreceptors activating the pupil should be readily achieved by measuring the spectral characteristics of the response of the pupil to retinal stimulation. Laurens (1923) was able to demonstrate that the curve relating pupil size to wave-length (equal energy spectrum) depended upon the adaptation state of the eye. The curve for the light-adapted eye had a minimum at 554-2 m,u, the dark-adapted curve had one at 514-3 m,u. This suggests that both rods and cones may influence the size of the pupil. Since, however, the relation between pupil size and intensity of the stimulating light is non-linear, such curves tell us nothing about the amount of energy necessary at each wave-length in the spectrum to produce a constant response. It is the information obtained from this kind of curve (an action spectrum) that is required in order to compare any non-linear physiological-response characteristic to an absorption spectrum of a visual pigment or to the well-documented spectral sensitivity curves of the visual rods and cones.

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Section: Part III Scotopic Responsesupporting

confidence: 54%

“…To the dark-adapted eye stimulus flashes which are below pupillary threshold are still quite visible (Schweitzer, 1956). (For flashes including the entire visual field this is no longer true, and so De Launay's (1949) result was probably fortuitous for the size ofthe field (2°) which he selected.)…”

Section: Resultsmentioning

confidence: 99%

The spectral sensitivity of the consensual light reflex

Alpern¹,

Campbell²

1962

The Journal of Physiology

114

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“…To our knowledge this is the first study to show the functional involvement of a rhodopsin-based mechanism at such advanced age in the RCS rat. It is likely that the pathways which mediate the light reflex can integrate activity over large retinal areas (Schweitzer, 1955;Bouma, 1965). The gain introduced by pooling over such large areas could suffice to provide a scotopit input to the pupillary light reflex even with very few rod photoreceptors remaining.…”

Section: Sprctrul Sensiticitrmentioning

confidence: 99%

“…This confirmed that in the rat, as in humans, the light reflex depends on stimulation of photoreceptors in the retina. The pupillary system has a considerable gain and a unitary response, presumed to reflect activity integrated over large retinal areas (Bouma, 1965;Schweitzer, 1955). These characteristics made the pupillary light reflex an ideal response with which to study the absolute sensitivity of the retina to light and the spectral sensitivity throughout the lifespan of the RCS rat.…”

Section: Introductionmentioning

confidence: 99%

Retinal sensitivity measured by the pupillary light reflex in RCS and albino rats

Trejo

Cicerone

1982

Vision Research

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Abstract-The effects of retinal degeneration on the sensitivity of the retina were studied in the RoyalCollege of Surgeons (RCS) rat by measuring the light reflex of the pupil in response to ganzfeld (full field) flashes. Light reflex thresholds were measured for animals from 32 to 683 days of age, and an age-related decrease in sensitivity of 5.2 log units (maximum) was measured. In contrast, thresholds for non-dystrophic albino controls increased only slightly during a comparable period. RCS rat thresholds increased more for short wavelength light than for long wavelength light.

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“…They provided a formula which does not asymptote at 2 mm and was a better fit to their mean than the formula of Moon and Spencer (1944) Stanley and Davies (1995) Crawford (1936) and Bouma (1965) demonstrated that pupil size was dependent not on luminance alone, but approximately on the product of luminance and adapting field size. This observation appears as early as Aubert (1876) [quoted in Schweitzer (1956)], but it did not appear in formulas for pupil size until the work of Stanley and Davies (1995), who measured pupil diameter for six observers as a function of luminance and adapting field sizes ranging in diameter from 0.4 to 25.48. They observed a strong effect of field size, which they suggested might account for the large discrepancies in earlier published results.…”

Section: à2mentioning

confidence: 98%

143 A Unified Formula For Light-adapted Pupil Size

Watson

Yellott

2012

SciVee

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The size of the pupil has a large effect on visual function, and pupil size depends mainly on the adapting luminance, modulated by other factors. Over the last century, a number of formulas have been proposed to describe this dependence. Here we review seven published formulas and develop a new unified formula that incorporates the effects of luminance, size of the adapting field, age of the observer, and whether one or both eyes are adapted. We provide interactive demonstrations and software implementations of the unified formula.

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Threshold measurements on the light reflex of the pupil in the dark adapted eye

Cited by 32 publications

References 27 publications

The spectral sensitivity of the consensual light reflex

The spectral sensitivity of the consensual light reflex

Retinal sensitivity measured by the pupillary light reflex in RCS and albino rats

143 A Unified Formula For Light-adapted Pupil Size

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