The Response of Intraocular Pressure to Systemic Hypercapnia and Hyperoxia

NCT01325285 | Unknown

• 1 other identifier: 10-0655
• Study Type: observational
• Target: 14
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this study is to determine how intraocular pressure responds to changes in the levels of carbon dioxide or oxygen that a healthy individual inspires.

Conditions

Intraocular Pressure

Keywords

Intraocular pressure; Hypercapnia; Hyperoxia; Rebreathing circuit

Outcome Measures

Primary Outcomes (1)

• Intraocular pressure

  Intraocular pressure will be measured using Goldmann applanation tonometry.

  Intraocular pressure will be measured during the study visit, ten minutes into each of the seven inhaled gas provocation stages

Secondary Outcomes (1)

• Retinal blood flow

  Retinal blood flow will be measured during the second (optional) study visit, ten minutes into each of the seven inhaled gas provocation stages

Interventions

RespirAct DEVICE

Participants will breathe through a mask connected to a sequential rebreathing circuit and gas blender. The following seven gas stages will be targeted for about 10 minutes each: 1. Baseline, measured in eye A (PETCO2=38mmHg and PETO2=100mmHg) 2. 10% hypercapnic increase, measured in eye A (PETCO2=42mmHg and PETO2=100mmHg) 3. 20% hypercapnic increase, measured in eye A (PETCO2=46mmHg and PETO2=100mmHg) 4. Baseline, measured in both eyes (PETCO2=38mmHg and PETO2=100mmHg) 5. 250% hyperoxic increase, measured in eye B (PETCO2=38mmHg and PETO2=250mmHg) 6. 500% hyperoxic increase, measured in eye B (PETCO2=38mmHg and PETO2=500mmHg) 7. Baseline, measured in eye B (PETCO2=38mmHg and PETO2=100mmHg)

Also known as: Inhaled gas provocations

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Healthy young individuals (age 18-30)

You may qualify if:

• Age range 18-30 years old
• Visual acuity of 20/20 or better

You may not qualify if:

• Refractive error \>±6.00 DS and/or ± 2.00 DC
• History or presence of ocular disease
• Family history of diabetes or glaucoma
• History of intraocular or refractive surgery
• Nursing or pregnant women
• History of clinically diagnosed endocrine disease
• History of vascular disease, cardiovascular disease, or any treated respiratory disorders (seasonal asthma excluded from this so long as subject not taking Rx at the time)
• History of systemic hypertension
• Habitual smoking
• Use of medications that affect blood flow

Sponsors & Collaborators

• University of Toronto: lead
• University Health Network, Toronto: collaborator
• Thornhill Research: collaborator

Study Sites (1)

Toronto Western Hospital

Toronto, Ontario, Canada

Location

Related Publications (2)

• Hosking SL, Harris A, Chung HS, Jonescu-Cuypers CP, Kagemann L, Roff Hilton EJ, Garzozi H. Ocular haemodynamic responses to induced hypercapnia and hyperoxia in glaucoma. Br J Ophthalmol. 2004 Mar;88(3):406-11. doi: 10.1136/bjo.2002.008995.

  PMID: 14977778 BACKGROUND

• Slessarev M, Han J, Mardimae A, Prisman E, Preiss D, Volgyesi G, Ansel C, Duffin J, Fisher JA. Prospective targeting and control of end-tidal CO2 and O2 concentrations. J Physiol. 2007 Jun 15;581(Pt 3):1207-19. doi: 10.1113/jphysiol.2007.129395. Epub 2007 Apr 19.

  PMID: 17446225 BACKGROUND

MeSH Terms

Conditions

Hypercapnia; Hyperoxia

Condition Hierarchy (Ancestors)

Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Christopher Hudson, PhD

  University of Toronto

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Alanna Adleman, BSc

CONTACT

416-603-5694; aadleman@uhnresearch.ca

Tien Wong, BSc

CONTACT

416-603-5694; twong@uhnresearch.ca

Study Design

• Study Type: observational
• Observational Model: CASE ONLY
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER

Study Record Dates

• First Submitted: February 15, 2011
• First Posted: March 29, 2011
• Study Start: August 1, 2011
• Primary Completion: September 1, 2011
• Study Completion: September 1, 2011
• Last Updated: August 18, 2011

Record last verified: 2010-11

Locations

CA (1)