Matches in SemOpenAlex for { <https://semopenalex.org/work/W3009377008> ?p ?o ?g. }
Showing items 1 to 81 of
81
with 100 items per page.
- W3009377008 abstract "This work investigates the effects of the anticholinesterases physostigmine and pyridostigmine and the cholinergic antagonists atropine and homatropine on the human visual system. The antagonism between these classes of drug is also assessed. Anticholinesterases cause pupillary constriction and an increase in accommodation. As a means of simulating their effects in a controlled situation, a systematic study was performed to determine the effects of artificial pupils and defocusing lenses on visual performance. This was assessed by measuring contrast sensitivity for the detection of sinusoidal grating patterns. Contrast sensitivity was measured in 12 subjects for a range of spatial frequencies (0.5-38 c/deg), for pupil diameters 2 - 8mm and for defocuses of +1 to +4 D, following homatropine eyedrops. Changes in pupil diameter, without any compensation for the change in retinal illumination, had no significant effect on contrast sensitivity, except at 0.5 and 1 c/deg when a significant reduction occurred with the 2mm pupil. This suggests that the expected improvement in optical quality associated with smaller pupil diameters had been annulled by the accompanying reduction in retinal illumination. On the other hand, defocus caused an appreciable reduction in contrast sensitivity at spatial frequencies higher than the peak of the contrast sensitivity function (3 c/deg) and a smaller reduction below the peak. With increasing defocus a downwards parallel shift of the contrast sensitivity function above the peak was observed. Each dioptre of defocus reduced contrast sensitivity by about 50% at spatial frequencies higher than peak and 19% at spatial frequencies lower than peak in the homatropinised eye. The decrements were slightly less in the natural eye. An oral dose of 60mg pyridostigmine bromide which causes at least a 20% inhibition of blood cholinesterase, caused a small but significant increase of 7% in contrast sensitivity to stationary oscilloscopegenerated grating patterns over 3-38 c/deg, for a group of 13 subjects. This was attributed to an increase in ocular quality due to the small reduction in pupil diameter. Contrast sensitivity to laser interference fringes observed in the Maxwellian view, were unchanged after pyridostigmine. It is concluded that pyridostigmine may be used as a pre-treatment against organophosphorus anticholinesterases without adverse effects on stationary visual function. Instillation of 0. 25% physostigmine sulphate eyedrops in 12 subjects caused a sustained miosis, a transient increase of near point accommodation and amplitude of involuntary accommodation. This last effect was maximal at 30 min and subsided by 90 min, though its amplitude varied greatly between subjects from +0.5D to +10D. Comparisons between two families of three siblings suggested involvement of a genetic trait in the amplitude of response of the ciliary body to physostigmine. Contrast sensitivity to externally-viewed oscilloscope grating patterns was transiently reduced after physostigmine and correlated with the increase in amplitude of accommodation. Physostigmine had a transient deleterious effect on contrast sensitivity to laser interference fringes, particularly at higher spatial frequencies, which was not affected by defocus of the image. Physostigmine also caused a prolonged reduction in contrast sensitivity to low spatial frequency grating patterns. Since the control eye showed no miosis, systemic absorption of physostigmine seems improbable. This suggests that there is a direct effect from trans-comeal absorption of physostigmine on the retinal neurones. The effects of a single intramuscular injection of 2mg atropine sulphate on visual performance were studied in 13 subjects. The well known actions of atropine on heart rate, secretion of saliva, dilatation of pupils and reduction in the amplitude of accommodative range, were observed. However, visual acuity, stereoacuity, red-green colour balance and reaction time to a visual stimulus were unaffected by atropine, although extra-ocular muscle balance was transiently changed. There was no significant change in contrast sensitivity to stationary sinusoidal gratings of spatial frequencies 1-30 c/deg for oscilloscope-generated patterns and laser interference fringes. However, contrast sensitivity to low spatial frequency (1-5 c/deg) grating patterns phase-reversed at 5.5 Hz showed a sustained reduction over six hours post-injection. Thus, it is concluded that atropine has an adverse effect on movement detection but not on stationary visual function. (Abstract shortened by ProQuest.)." @default.
- W3009377008 created "2020-03-13" @default.
- W3009377008 creator A5039834061 @default.
- W3009377008 date "1989-01-01" @default.
- W3009377008 modified "2023-09-23" @default.
- W3009377008 title "Actions of Anticholinesterases on Visual Performance in Man and Their Antagonism by Atropine" @default.
- W3009377008 hasPublicationYear "1989" @default.
- W3009377008 type Work @default.
- W3009377008 sameAs 3009377008 @default.
- W3009377008 citedByCount "0" @default.
- W3009377008 crossrefType "dissertation" @default.
- W3009377008 hasAuthorship W3009377008A5039834061 @default.
- W3009377008 hasConcept C100921725 @default.
- W3009377008 hasConcept C118487528 @default.
- W3009377008 hasConcept C119767625 @default.
- W3009377008 hasConcept C120665830 @default.
- W3009377008 hasConcept C121332964 @default.
- W3009377008 hasConcept C126322002 @default.
- W3009377008 hasConcept C127413603 @default.
- W3009377008 hasConcept C185592680 @default.
- W3009377008 hasConcept C21200559 @default.
- W3009377008 hasConcept C24326235 @default.
- W3009377008 hasConcept C259533 @default.
- W3009377008 hasConcept C2775859210 @default.
- W3009377008 hasConcept C2775910092 @default.
- W3009377008 hasConcept C2776502983 @default.
- W3009377008 hasConcept C2776663719 @default.
- W3009377008 hasConcept C2777394604 @default.
- W3009377008 hasConcept C2778257484 @default.
- W3009377008 hasConcept C2780827179 @default.
- W3009377008 hasConcept C3019054092 @default.
- W3009377008 hasConcept C42219234 @default.
- W3009377008 hasConcept C71924100 @default.
- W3009377008 hasConceptScore W3009377008C100921725 @default.
- W3009377008 hasConceptScore W3009377008C118487528 @default.
- W3009377008 hasConceptScore W3009377008C119767625 @default.
- W3009377008 hasConceptScore W3009377008C120665830 @default.
- W3009377008 hasConceptScore W3009377008C121332964 @default.
- W3009377008 hasConceptScore W3009377008C126322002 @default.
- W3009377008 hasConceptScore W3009377008C127413603 @default.
- W3009377008 hasConceptScore W3009377008C185592680 @default.
- W3009377008 hasConceptScore W3009377008C21200559 @default.
- W3009377008 hasConceptScore W3009377008C24326235 @default.
- W3009377008 hasConceptScore W3009377008C259533 @default.
- W3009377008 hasConceptScore W3009377008C2775859210 @default.
- W3009377008 hasConceptScore W3009377008C2775910092 @default.
- W3009377008 hasConceptScore W3009377008C2776502983 @default.
- W3009377008 hasConceptScore W3009377008C2776663719 @default.
- W3009377008 hasConceptScore W3009377008C2777394604 @default.
- W3009377008 hasConceptScore W3009377008C2778257484 @default.
- W3009377008 hasConceptScore W3009377008C2780827179 @default.
- W3009377008 hasConceptScore W3009377008C3019054092 @default.
- W3009377008 hasConceptScore W3009377008C42219234 @default.
- W3009377008 hasConceptScore W3009377008C71924100 @default.
- W3009377008 hasLocation W30093770081 @default.
- W3009377008 hasOpenAccess W3009377008 @default.
- W3009377008 hasPrimaryLocation W30093770081 @default.
- W3009377008 hasRelatedWork W132998694 @default.
- W3009377008 hasRelatedWork W1964510961 @default.
- W3009377008 hasRelatedWork W1977778988 @default.
- W3009377008 hasRelatedWork W1981732381 @default.
- W3009377008 hasRelatedWork W1988458813 @default.
- W3009377008 hasRelatedWork W1988719369 @default.
- W3009377008 hasRelatedWork W1991013967 @default.
- W3009377008 hasRelatedWork W1996964158 @default.
- W3009377008 hasRelatedWork W2025419469 @default.
- W3009377008 hasRelatedWork W2029994538 @default.
- W3009377008 hasRelatedWork W2031419138 @default.
- W3009377008 hasRelatedWork W2050711759 @default.
- W3009377008 hasRelatedWork W2091736650 @default.
- W3009377008 hasRelatedWork W2166331246 @default.
- W3009377008 hasRelatedWork W2167972235 @default.
- W3009377008 hasRelatedWork W2336955999 @default.
- W3009377008 hasRelatedWork W2352722799 @default.
- W3009377008 hasRelatedWork W2409869526 @default.
- W3009377008 hasRelatedWork W315653681 @default.
- W3009377008 hasRelatedWork W95443593 @default.
- W3009377008 isParatext "false" @default.
- W3009377008 isRetracted "false" @default.
- W3009377008 magId "3009377008" @default.
- W3009377008 workType "dissertation" @default.