The Effect of Graded Forced Expiration on Intraocular Pressure

NCT07274176 | Recruiting

• 1 other identifier: AB&AYK
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Intraocular Pressure

Outcome Measures

Primary Outcomes (1)

• Intraocular Pressure Measurement

  The intraocular pressure will be measured in both eyes using a calibrated Tonoref III non-contact tonometry (Nidek Co., Ltd., Gamagori, Aichi, Japan) and applanation tonometry (A900 tonometer, Costruzione Strumenti Oftalmici, Firenze, Italy) by a single examiner

  T0: Baseline / T1: after 1 minute of forced expiration at Level 1 /T2: after 1 minute of forced expiration at Level 2/T3: Immediately after 1 minute of forced expiration at Level 3

Study Arms (1)

Forced expiration program

EXPERIMENTAL

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).

Other: Intraocular Pressure after forced expiration

Interventions

Intraocular Pressure after forced expiration OTHER

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.

Forced expiration program

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Aged 18 years or older.
• 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.

You may not qualify if:

• a history of intraocular surgery,
• a history of uveitis,
• a spherical refractive error exceeding 3D,
• a history of regular topical treatment other than artificial tears

Sponsors & Collaborators

• Uşak University: lead

Study Sites (1)

University of Usak

Uşak, 64200, Turkey (Türkiye)

RECRUITING

Study Officials

• Ali Y Karahan, Prof.

  University of Usak

  STUDY CHAIR

Central Study Contacts

Ata Baytaroglu, Asst. Prof.

CONTACT

+905379315396; ata.baytaroglu@usak.edu.tr

Serife N Ciftci, Asst. Prof.

CONTACT

+905379315396; ciftciserifenur@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: SCREENING
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: A prospective, cross-sectional, single-visit study designed to measure the acute effect of a standardized respiratory exercise session on intraocular pressure (IOP).

Study Record Dates

• First Submitted: November 27, 2025
• First Posted: December 10, 2025
• Study Start: December 15, 2025
• Primary Completion: February 10, 2026
• Study Completion: February 25, 2026
• Last Updated: December 22, 2025

Record last verified: 2025-12

Locations

TU (1)