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OpenTrials
Completed

NCT Number: NCT02965924

Effect of Topical Phenylephrine 2.5% on EVP in Normal Human Eyes

Phenylephrine hydrochloride ophthalmic solution is an alpha-1 adrenergic receptor agonist commonly used topically for dilation prior to ocular fundus examination. In the eye, phenylephrine acts locally as a potent vasoconstrictor and mydriatic by constricting ophthalmic blood vessels and the radial dilator muscle of the iris. Episcleral venous pressure (EVP) is a determinant of intraocular pressure (IOP) and can be measured non-invasively by venomanometry. Since phenylephrine is a vasoconstrictor, it may affect episcleral venous tone, but the effect on EVP is unknown. Understanding the physiology of episcleral veins helps us in better understanding of pathophysiology of glaucoma.

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Key information

Conditions

Assess Phenylephrine on EVP and IOP

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Mayo Clinic in Rochester

Rochester, Minnesota, 55905, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Any self-declared ethno-racial category.
  • Medically healthy subjects.
  • Subjects with two healthy eyes.
  • Intraocular pressure (IOP) less than 22 mmHg in each eye.
  • Best-corrected visual acuity (BCVA) in each eye 20/50 or better.
  • Open angles in both eyes.
  • Contact lens wear stopped at least 3 days prior to study, and during the study.
  • Ability to cooperate for examinations required for study.

Exclusion criteria

  • Chronic or acute ophthalmic diseases including glaucoma, wet type macular degeneration, uveitis and clinically significant cataract.
  • Evidence of ocular infection, inflammation, clinically significant blepharitis or conjunctivitis.
  • Cornea pathologic changes preventing reliable measurement.
  • Narrow anterior chamber angle.
  • Previous intraocular surgeries, laser procedures, and intravitreal injections.
  • Previous corneal refractive surgeries.
  • Myopia greater than -6.00 D spherical equivalent.
  • Hyperopia greater than +2.00 D spherical equivalent.
  • Lack of suitable episcleral vein for measurement.
  • Ocular trauma within the past 6 months.
  • Ocular infection or ocular inflammation in the past 3 months.
  • Ocular medication of any kind within 30 days of study visit.
  • Known hypersensitivity to Phenylephrine or topical anesthetic medication.
  • Severe hypertension: Systolic blood pressure greater than 180 mmHg and/or diastolic blood pressure greater than 105 mmHg.
  • A known history of ischemic heart disease (angina or myocardial infarction), cerebrovascular accidents, cardiac arrhythmias, cerebral or aortic aneurysms.
  • Uncontrolled diabetes mellitus.
  • Uncontrolled hyperthyroidism.
  • Use of some systemic medications within 30 days prior to study including: β-adrenergic antagonists, α-adrenergic agonists and antagonists, calcium channel blockers, diuretics, vasodilators, monoamine oxidase inhibitors, and systemic steroids.
  • Participation in any interventional study within the past 30 days prior to study visit.
  • Women who are pregnant.

Treatment and study plan

Phenylephrine 2.5%

Drug

Instilling phenylephrine 2.5% eye drop

Primary outcomes

  1. Change in Episcleral Venous Pressure (EVP)

    Time frame: baseline, 60 minutes

    EVP will be measured non-invasively using a custom-modified slit-lamp mounted venomanometer. This device utilizes the pressure chamber technique, in which a clear flexible balloon is placed against the conjunctival surface of the eye, and the pressure is increased until an episcleral vein is noted to blanch. The system for pressure-chamber based venomanometry includes a computer-controlled motor drive to increase pressure automatically, a transducer to record pressure, and a high-definition video camera to record vein collapse. Pressure measurements are synchronized with the video stream and image analysis software is used to determine the pressure required to collapse the vein to a specific pre-determined degree as measured in mmHg.

Secondary outcomes

  1. Change in Intraocular Pressure (IOP)

    Time frame: baseline, 60 minutes

    Intraocular pressure will be measured in mmHg after topical anesthesia by using the pneumatonometer. There will be a minimum of three IOP measurements and a mean will be accepted as IOP.

Sponsors and collaborators

Lead sponsor

Mayo Clinic

Other

Registry information

Official study title

Effect of Topical Phenylephrine 2.5% on Episcleral Venous Pressure in Normal Human Eyes

Important dates

Study start
2016
Primary completion
2018
Study completion
2018
First posted
Nov 17, 2016
Registry last updated
Oct 23, 2019

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.