Effect of Topical Phenylephrine 2.5% on Episcleral Venous Pressure in Normal Human Eyes
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- Mayo Clinic
- 入组人数
- 20
- 试验地点
- 1
- 主要终点
- Change in Episcleral Venous Pressure (EVP)
研究概览
简要总结
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •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.
排除标准
- •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.
研究组 & 干预措施
Phenylephrine
Subjects will receive topical phenylephrine 2.5% eye drop instilled in one eye after all baseline measurements.
干预措施: Phenylephrine 2.5% (Drug)
结局指标
主要结局
Change in Episcleral Venous Pressure (EVP)
时间窗: 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.
次要结局
- Change in Intraocular Pressure (IOP)(baseline, 60 minutes)
研究者
Arthur J. Sit, M.D.
Principal Investigator
Mayo Clinic