The Effects of Physostigmine Sulphate Eyedrops on Human Visual Function

Kay, C. D.; Morrison, J. D.

doi:10.1113/expphysiol.1988.sp003170

Cited by 4 publications

(8 citation statements)

References 20 publications

(32 reference statements)

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“…Previously, we showed that ocular instillation of physostigmine sulphate transiently reduced contrast sensitivity, with the nadir at 30 min and recovery by 90 min (Kay & Morrison, 1988). The deficit was contributed to both by the defocus resulting from the transient increase in accommodation and by a direct effect on the visual system.…”

Section: Introductionmentioning

confidence: 84%

“…This improvement was attributed entirely to the increased depth of focus resulting from a miosis of 1 mm. So it is by no means clear whether organophosphorus anticholinesterases do effect spasm of accommodation in the way that physostigmine does (Kay & Morrison, 1988). If not, then this is a most remarkable difference for organophosphorus anticholinesterases which are noted for their great potency.…”

Section: Discussionmentioning

confidence: 99%

“…A full description of the apparatus and experimental methods is presented in the accompanying paper (Kay & Morrison, 1988).…”

Section: Methodsmentioning

confidence: 99%

“…Since organophosphorus agents cannot be used in the laboratory, we have instead used physostigmine eyedrops against which the effectiveness of intramuscular injection of 2 mg atropine sulphate was tested. First, atropine sulphate was injected some 8 min prior to physostigmine eyedrops, in order that the peak plasma atropine concentration shown to occur at 30 min post-injection (Berghem, Bergman, Schildt & Sorbo, 1980) coincided with the peak action of physostigmine on contrast sensitivity and defocus (Kay & Morrison, 1988). Second, atropine sulphate was injected some 120 min prior to physostigmine to allow its ocular actions in dilating the pupil and reducing near-point accommodation to develop fully (Kay & Morrison, 1987a).…”

Section: Introductionmentioning

confidence: 99%

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An Evaluation of the Effectiveness of Intramuscular Atropine or Homatropine Eyedrops in Preventing the Effects of Physostigmine Eyedrops on Human Vision

Kay

Morrison

1988

Exp Physiol

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SUMMARYAn intramuscular injection of 2 mg atropine sulphate was given at either 8 or 120 min prior to instillation of 0-25 % physostigmine sulphate eyedrops. In this way, the maximum accommodative change and the concomitant reduction in contrast sensitivity caused by physostigmine coincided with, respectively, the peak plasma atropine concentration or the fully developed mydriasis and reduction of near-point accommodation caused by atropine. Atropine at both times did not affect the miosis, the reduction in near-point, the increase in accommodation or the reduction in contrast sensitivity caused by physostigmine. Contrast sensitivity to a phasereversed grating pattern was actually diminished by atropine, though this was not statistically significant. By contrast, 2 % homatropine hydrobromide eyedrops did effectively anatagonize physostigmine's actions. This indicates that the rate of delivery of atropine from the intramuscular injection was insufficient to compete against the ocular effects of physostigmine.

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Section: Introductionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

“…A full description of the apparatus and experimental methods is presented in the accompanying paper (Kay & Morrison, 1988).…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An Evaluation of the Effectiveness of Intramuscular Atropine or Homatropine Eyedrops in Preventing the Effects of Physostigmine Eyedrops on Human Vision

Kay

Morrison

1988

Exp Physiol

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“…The most probable explanation is an effect of hyoscine directly on the retina, which is supported by its relatively rapid action on the iris and ciliary body (see Figure Z(a) and ( b ) ) . A precedent is the deleterious effect of physostigmine eyedrops on critical fusion frequency (Alpern and Jampel, 1959) and on contrast sensitivity to laser interference fringes (Kay and Morrison, 1988). The most probable route of absorption is transcorneal though systemic absorption from the nasal mucosa after drainage through the nasolacrimal canal may also arise (Shell, 1982).…”

Section: Contrast Sensitivitymentioning

confidence: 99%

The effects of 0.025% hyoscine hydrobromide eyedrops on visual function in man

Morrison

Reilly

1989

Ophthalmic Physiologic Optic

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Instillation of three drops of 0.025% hyoscine hydrobromide into one eye at 5 min intervals caused a mydriasis and cycloplegia of rapid onset and of 4-6 days' duration; this was similar to the previously reported actions of concentrations of up to 0.5%. After refraction for the working distance of the experiments, contrast sensitivity to stationary oscilloscope-generated grating patterns of 10 and 20 c/deg was unaffected despite the mydriasis. Also, contrast sensitivity to laser interference fringes of 10 and 20 c/deg observed in the Maxwellian view, in which the effects of the ocular media are bypassed, was unaffected. Contrast sensitivity to a 3 c/deg phase-reversed grating pattern was, however, transiently reduced by 40% after hyoscine. A second series of experiments showed a deleterious effect of hyoscine on contrast sensitivity to both stationary and phase-reversed grating patterns of 2, 3 and 5 c/deg while contrast sensitivity at 10 c/deg was not consistently affected. These results were explained by a direct deleterious action of hyoscine at the level of the retina, specific to channels that detect low spatial frequencies.

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Evaluation of two scopolamine and physostigmine pretreatment regimens against nerve agent poisoning in the dog

Bonhage

Chilcoat

et al. 2009

Vet Pharm & Therapeutics

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Currently, there is no viable protection against chemical warfare agents for the working dog. Physostigmine (PHY) and scopolamine (SCO) have been shown to protect dogs against nerve agents with minimal side effects. The goal of this study was to investigate whether reported protective SCO/PHY plasma concentrations of 0.2 and 0.7 ng/mL, respectively, could be reached and maintained with minimal side-effects thereby identifying possible pretreatment regimens. Two continuous regimens of SCO/PHY were administered to beagle dogs. The first regimen consisted of administering transdermal SCO and intraocular PHY, the second consisted of transdermal SCO and rectal PHY. SCO/PHY plasma concentrations for each regimen were determined, individual protective times were calculated and a computerized pharmacokinetic analysis was performed. The results showed transdermal SCO and intraocular PHY routes of delivery achieved sustained protective drug concentrations with minimal side-effects and the rectal route of delivery did not. Group median protective times for the first regimen were 54.45 h for SCO and 64.35 h for PHY, and for the second regimen 63.75 h for SCO and 0 h for PHY. The combined transdermal patch and intraocular regimen may provide a safe and effective regimen against nerve agent poisoning in dogs.

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The Effects of Physostigmine Sulphate Eyedrops on Human Visual Function

Cited by 4 publications

References 20 publications

An Evaluation of the Effectiveness of Intramuscular Atropine or Homatropine Eyedrops in Preventing the Effects of Physostigmine Eyedrops on Human Vision

An Evaluation of the Effectiveness of Intramuscular Atropine or Homatropine Eyedrops in Preventing the Effects of Physostigmine Eyedrops on Human Vision

The effects of 0.025% hyoscine hydrobromide eyedrops on visual function in man

Evaluation of two scopolamine and physostigmine pretreatment regimens against nerve agent poisoning in the dog

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