Intraocular Pressure in Non‐equilibrium States

Davanger, Martin; Holter, Ø.

doi:10.1111/j.1755-3768.1967.tb06515.x

Cited by 8 publications

(7 citation statements)

References 16 publications

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“…The pressure decays are compared with reference curves calculated (by a summation procedure) on the assumptions of a step-fall in the secretion of aqueous humour due to the acetazolamide, a well-defined relation between the volume and the pressure of the eye (Friedenwalds equation with an ocular rigidity of 0.0215), different values of the facility of aqueous outflow, and constant episcleral vein pressure. Goldmann &Schmidt (1965) and Davanger & Holter (1967) obtained a virtually identical pressuretime relation by integration. In many of the experiments an immediate graphic representation of the experimental curves was obtained by using an applanation tono-…”

Section: Summary Of the Methodsmentioning

confidence: 85%

The Immediate Response in Applanation Pressure to Intravenous Acetazolamide in Primary Glaucomas and Glaucoma Suspects

Nissen

1975

Acta Ophthalmologica

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The decays in the applanation pressures of both eyes, after a reduction of the aqueous secretion by means of intravenous acetazolamide, are studied with respect to shape and steepness by comparison with reference curves calculated from different values of the facility of aqueous outflow. The pressure decays in three out of four eyes with narrow-angle glaucoma exhibited "breaks" possibly resulting from a stepwise reopening of the chamber angle during the decompression. Twenty patients with intraocular hypertension and open angles could be divided into two groups according to the facility of aqueous outflow (in mul mmHg-1 min-1), estimated from approximately matching reference curves: Nine patients with facilities above 0.15 had normal visual fields and nearly indentical pressure curves of the two eyes. Out of 11 patients with facilities below 0.15, seven patients had glaucomatous visual field defects and excavated optic discs. The pressure curves of eye pairs in this low facility group showed asymmetry, and breaks were seen in approximately half of the curves. These might be caused by changes in the outflow facility due to a decompression of collapsed outflow channels. However, the morphological basis for such an interpretation is not as well founded as in the case of narrow-angle glaucoma.

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Section: Summary Of the Methodsmentioning

confidence: 85%

The Immediate Response in Applanation Pressure to Intravenous Acetazolamide in Primary Glaucomas and Glaucoma Suspects

Nissen

1975

Acta Ophthalmologica

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“…A non-equilibrium state in the ocular hydrodynamics of the type treated by Davanger & Holter (1967) might follow from e. g. an injection of a volume of fluid into the eye, or a sudden shift in the rate of aqueous secretion. In such 2, 72-82.…”

Section: Principlementioning

confidence: 99%

Model Computation of the Effect of Arbitrary Variations in Aqueous Inflow, Outflow Conductance, Ocular Rigidity and Episcleral Vein Pressure on Ocular Pressure

Nissen

1977

Acta Ophthalmologica

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Model calculations of the time course of the intraocular pressure are performed in cases where the four determinants mentioned in the title vary, singly or simultaneously, according to specified time functions. Assumptions are 1) that the outflow of the aqueous humor is proportional to the driving pressure, and 2) that the intraocular pressure and volume are related to each other as described by Friedenwald. The mathematical solution if numerical and involves the repetition of the same calculatory step process. It is rendered probable that the maximal inhibitory effect of acetazolamide on the secretion of aqueous humour is reached in less than one minute after the drug has reached the receptors. A programmable calculator with 224 storage locations is used, the programs are given.

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“…However, as the pressure decreases the indentation volume increases, with the result that. the 'pressure drop per unit time will be smaller in a tonography curve than in the pressure decay curves discussed earlier (Davanger & Holter 1967).…”

Section: Introductionmentioning

confidence: 98%

“…In experiments, this pressure curve may be directly registered electromanometrically (Langham & Eisenlohr 1963), or it may be plotted by repeated tonometries (Sgteren 1960, Galin et al 1962, Langham 1963, Armal y &-Halasa 1963ab, Chandler 1964. It was shown by Davanger & Holter (1967) that the eye's hydrodynamical parameters may be calculated from such experiments.…”

Section: Introductionmentioning

confidence: 98%

“…In a previous paper (Davanger & Holter 1967) a theoretical analysis of the pressure-time curve resulting from a disturbance of the eye's hydrodynamical equilibrium was presented. In experiments, this pressure curve may be directly registered electromanometrically (Langham & Eisenlohr 1963), or it may be plotted by repeated tonometries (Sgteren 1960, Galin et al 1962, Langham 1963, Armal y &-Halasa 1963ab, Chandler 1964.…”

Section: Introductionmentioning

confidence: 99%

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