The Effect of Graded Forced Expiration on Intraocular Pressure
NCT ID: NCT07274176
Last Updated: 2025-12-22
Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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RECRUITING
NA
60 participants
INTERVENTIONAL
2025-12-15
2026-02-25
Brief Summary
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Detailed Description
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While the effect of a maximal Valsalva is recognized, the quantitative relationship between graded levels of expiratory force and IOP remains poorly characterized. Previous studies have been limited by the inability to precisely control and measure respiratory effort, often relying on voluntary maneuvers that lack standardization and reproducibility.
The recent advent of portable respiratory muscle trainers, such as the Airofit device, offers a novel solution to this methodological challenge. This device enables the precise application of controlled, graded resistance to expiration across multiple predefined levels.
Therefore, the primary objective of this study is to utilize the Airofit device to systematically measure and characterize the changes in intraocular pressure across its six different levels of forced expiration. This investigation will provide crucial quantitative data on the IOP-respiratory effort relationship, enhancing our understanding of IOP dynamics during controlled respiratory stress and establishing a new, standardized paradigm for such research.
Methods
Study Design: A prospective, cross-sectional, single-visit study designed to measure the acute effect of a standardized respiratory exercise session on intraocular pressure (IOP).
Participants and Recruitment
A convenience sample of 60 adult participants will be recruited from outpatient clinics of physical medicine and rehabilitation of Usak university
Participants will be provided with a full information sheet and will sign a written informed consent form prior to any study procedures.
Conditions
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Study Design
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NA
SINGLE_GROUP
SCREENING
NONE
Study Groups
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Forced expiration program
The participants will be equipped with the Airofit respiratory muscle trainer and will be provided with standardised instructions on performing forced expiration manoeuvres.
Participants will be fitted with the Airofit respiratory muscle trainer and given standardized instructions on performing forced expiration maneuvers.
* The protocol consisted of sequentially performing forced expiration at each of the device's six predefined resistance levels (Level 1 being the lowest, Level 6 the highest).
* The sequence for each level will be identical and as follows:
* Exercise Phase: The participant will perform forced expiration maneuvers with the Airofit device for a duration of 5 minute at the specified resistance level.
* Immediate Post-Exercise Measurement: Within 5 seconds of completing the exercise minute, IOP will be measured. This measurement will be labeled accordingly: T1 (after Level 1), T2 (after Level 2), up to T6 (after Level 6).
Intraocular Pressure after forced expiration
The experiment will entail the acquisition of a total of seven intraocular pressure (IOP) measurements from each subject.
* T0: Baseline (pre-intervention, resting).
* T1: Immediately after 1 minute of forced expiration at Level 1.
* T2: Immediately after 1 minute of forced expiration at Level 2.
* T3: Immediately after 1 minute of forced expiration at Level 3.
* T4: Immediately after 1 minute of forced expiration at Level 4.
* T5: Immediately after 1 minute of forced expiration at Level 5.
* T6: Immediately after 1 minute of forced expiration at Level 6.
Interventions
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Intraocular Pressure after forced expiration
The experiment will entail the acquisition of a total of seven intraocular pressure (IOP) measurements from each subject.
* T0: Baseline (pre-intervention, resting).
* T1: Immediately after 1 minute of forced expiration at Level 1.
* T2: Immediately after 1 minute of forced expiration at Level 2.
* T3: Immediately after 1 minute of forced expiration at Level 3.
* T4: Immediately after 1 minute of forced expiration at Level 4.
* T5: Immediately after 1 minute of forced expiration at Level 5.
* T6: Immediately after 1 minute of forced expiration at Level 6.
Eligibility Criteria
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Inclusion Criteria
* Willing and able to provide informed consent.
* Have a best-corrected visual acuity of 6/12 or better.
* Able to understand and follow instructions for using the Airofit device.
* Have an optic nerve cup/disc ratio not exceeding 0.5, and have a c/d difference between both eyes not exceeding 0.2.
* Did not have taken any anticholinergic medication, systemic beta-blockers, or corticosteroids within the last 3 months that could affect intraocular pressure levels.
Exclusion Criteria
* a history of uveitis,
* a spherical refractive error exceeding 3D,
* a history of regular topical treatment other than artificial tears
18 Years
65 Years
ALL
Yes
Sponsors
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Uşak University
OTHER
Responsible Party
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Ali Yavuz Karahan
Professor
Principal Investigators
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Ali Y Karahan, Prof.
Role: STUDY_CHAIR
University of Usak
Locations
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University of Usak
Uşak, , Turkey (Türkiye)
Countries
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Central Contacts
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Facility Contacts
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Ali Y Karahan
Role: primary
Other Identifiers
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AB&AYK
Identifier Type: -
Identifier Source: org_study_id