Effects of antiglaucoma drugs on ocular hemodynamics in healthy volunteers

Schmetterer, Leopold; Strenn, Karin; Findl, Oliver; Breiteneder, Helene; Graselli, Ursula; Agneter, Ernst; Eichler, Hans‐Georg; Wolzt, Michael

doi:10.1016/s0009-9236(97)90138-7

Cited by 80 publications

(64 citation statements)

References 40 publications

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“…16 In another study assessing fundus pulsations, topical clonidine or dipivefrin significantly decreased fundus pulsations in the macula and the optic disc. 45 In the present study in rabbits, the ipsilateral significant decrease of both NB ONH by maximum of 9% and NB CH by maximum of 20% in the phenylephrinetreated eyes was evident at 30 min after the instillation and continued over an hour, whereas no significant change was found in the contralateral eyes. The IOP showed a tendency to decrease in the phenylephrinetreated eyes, as previously studied in rabbits, 46 whereas the blood pressure remained unchanged.…”

Section: Discussioncontrasting

confidence: 42%

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Topical phenylephrine decreases blood velocity in the optic nerve head and increases resistive index in the retinal arteries

Takayama

Mayama

Mishima

et al. 2008

Eye

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Purpose To investigate the effects of topical phenylephrine on circulation in the optic nerve head (ONH), posterior choroids, or retina in rabbits and healthy humans. Methods Tissue blood velocity in the ONH and posterior choroid was measured using the laser speckle method as normalized blur (NB ONH and NB CH ) in 28 anaesthetized albino rabbits. NB and intraocular pressure (IOP) in both eyes were measured for 180 min after unilateral single instillation of 5% phenylephrine and contralateral physiological saline as a control. In 11 normal volunteers aged 26.0±2.7 years, NB ONH was measured for 180 min after unilateral three drops of 5% phenylephrine and contralateral physiological saline in a double-masked manner. In the other 17 normal volunteers aged 25.5 ± 2.4 years, blood velocity and blood flow in a major branch of the central retinal artery were measured using the laser Doppler blood flow metre and IOP and systemic circulatory parameters were monitored in similar fashion. Analysis of variance was applied for intergroup comparisons.Results NB ONH and NB CH decreased significantly only in the phenylephrinetreated eyes in rabbits by maximum of 9 and 20%, respectively (P ¼ 0.0046 and 0.0009), despite IOP decrease. In humans, NB ONH decreased significant by maximum of 13% (P ¼ 0.0047) and resistive index in the retinal arteries increased by 10% (P ¼ 0.0067) unilaterally; whereas IOP, diameter, blood velocity, or blood flow of the arteries was not significantly changed. Conclusion Topical phenylephrine could exert a significant unfavourable effect on circulation in the ONH, choroidal tissue, and retinal arteries in rabbits and normal young humans.

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Section: Discussioncontrasting

confidence: 42%

“…45 On the other hand, it is not clear whether the increased RI in the temporal retinal artery is attributed to direct effect of phenylephrine on the retinal branch arteries or central retinal artery. No significant change in the blood flow despite the increased RI may be explained by autoregulatory mechanism of retinal circulation.…”

Section: Discussionmentioning

confidence: 99%

Topical phenylephrine decreases blood velocity in the optic nerve head and increases resistive index in the retinal arteries

Takayama

Mayama

Mishima

et al. 2008

Eye

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“…79 In contrast, studies conducted in patients with glaucoma as well as in healthy volunteers found no effect of pilocarpine on the pulsatile component of ocular blood flow. 80,81 There is no study supporting that parasympathomimetics exert any non-IOPrelated neuroprotective effects in glaucoma patients.…”

Section: Topical Therapiesmentioning

confidence: 99%

Pharmacotherapy of Glaucoma

Schmidl

Schmetterer²,

Garhöfer³

et al. 2015

Journal of Ocular Pharmacology and Therapeutics

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136

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Glaucoma is a group of diseases involving the optic nerve and associated structures, which is characterized by progressive visual field loss and typical changes of the optic nerve head (ONH). The only known treatment of the disease is reduction of intraocular pressure (IOP), which has been shown to reduce glaucoma progression in a variety of large-scale clinical trials. Nowadays, a relatively wide array of topical antiglaucoma drugs is available, including prostaglandin analogues, carbonic anhydrase inhibitors, beta-receptor antagonists, adrenergic agonists, and parasympathomimetics. In clinical routine, this allows for individualized treatment taking risk factors, efficacy, and safety into account. A major challenge is related to adherence to therapy. Sustained release devices may help minimize this problem but are not yet available for clinical routine use. Another hope arises from non-IOP-related treatment concepts. In recent years, much knowledge has been gained regarding the molecular mechanisms that underlie the disease process in glaucoma. This also strengthens the hope that glaucoma therapy beyond IOP lowering will become available. Implementing this concept with clinical trials remains, however, a challenge.

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“…The short-term and day-to-day variability of the method is small, which allows detection of even minor changes in local pulsatile blood flow following pharmacological stimulation. 11 In contrast to systems recording ocular pressure pulse, 12-14 information on the ocular circulation can be obtained with high transverse resolution. To obtain information on the choroidal blood flow, the macula, which lacks retinal vasculature, was chosen for measurements.…”

Section: Fundus Pulsationsmentioning

confidence: 99%

Effects of Acetazolamide on Choroidal Blood Flow

Dallinger

Bobr

Findl

et al. 1998

Stroke

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Background and Purpose-The acetazolamide provocation test is commonly used to study cerebrovascular vasomotor reactivity. On the basis of the effect of a carbonic anhydrase inhibitor in the central nervous system, we hypothesized that acetazolamide may also increase blood flow in the human choroid. Methods-In a placebo-controlled, randomized, double-blind, three-way crossover design, acetazolamide (500 mg or 1000 mg IV) or placebo was administered to nine healthy subjects. The effect of acetazolamide was studied at 15-minute intervals for 90 minutes. Pulsatile choroidal blood flow was assessed with laser interferometric measurement of fundus pulsation. In addition, mean blood flow velocity and resistive index in the ophthalmic artery were measured with Doppler sonography. In a second study in six healthy subjects, we assessed the effect of acetazolamide (1000 mg IV) on intraocular pressure. Results-Acetazolamide increased fundus pulsation amplitude in a dose-dependent manner (1000 mg: ϩ33%; 500 mg: ϩ20%; PϽ0.001, ANOVA). The effect of acetazolamide on MFV (1000 mg: ϩ18%; 500 mg: ϩ8%; Pϭ0.003, ANOVA) and RI (1000 mg: Ϫ4%; 500 mg: Ϫ2%; Pϭ0.006, ANOVA) was less pronounced but also significant. Acetazolamide did not induce any changes in systemic hemodynamic parameters but significantly decreased intraocular pressure (1000 mg: Ϫ37%; PϽ0.0001). Conclusions-The present data show for the first time that intravenously administered acetazolamide increases choroidal blood flow in humans. This phenomenon therefore indicates that the acetazolamide provocation test may qualify as a tool to investigate ocular vasomotor reactivity in a variety of ocular diseases. Moreover, the increase in choroidal blood flow after carbonic anhydrase inhibition can be expected to contribute to the therapeutic efficacy of carbonic anhydrase inhibitors in glaucoma. (Stroke. 1998;29:997-1001.)

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Effects of antiglaucoma drugs on ocular hemodynamics in healthy volunteers

Cited by 80 publications

References 40 publications

Topical phenylephrine decreases blood velocity in the optic nerve head and increases resistive index in the retinal arteries

Topical phenylephrine decreases blood velocity in the optic nerve head and increases resistive index in the retinal arteries

Pharmacotherapy of Glaucoma

Effects of Acetazolamide on Choroidal Blood Flow

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