Intraocular Pressure During Static Apnea

Intraocular Pressure Changes During Dry Static Apnea in Breath-Hold Divers

This prospective observational study evaluated changes in intraocular pressure (IOP) during dry static apnea (STA) in breath-hold divers. Forty participants performed voluntary breath-holds while intraocular pressure, peripheral oxygen saturation (SpO2), heart rate, and blood pressure were measured at baseline, during apnea, and after apnea. The aim was to assess the magnitude and dynamics of IOP changes and their relationship to physiological parameters.

Study Overview

• Status: Completed
• Conditions: Apnea; Glaucoma; Intraocular Pressure

Detailed Description

Breath-hold diving is associated with marked physiological changes, including hypoxemia, hypercapnia, bradycardia, and increases in blood pressure. The effect of prolonged breath-holding on intraocular pressure (IOP) remains insufficiently understood.

This prospective observational study investigated changes in intraocular pressure during dry static apnea (STA) in adult breath-hold divers. Participants performed breath-holds in a supine position after a standardized resting period.

Intraocular pressure was measured using a rebound tonometer (Icare Pro, Icare Finland Oy, Helsinki, Finland). Blood pressure was measured using an automated sphygmomanometer (Omron M6 Comfort, Omron Healthcare, Kyoto, Japan). Peripheral oxygen saturation and heart rate were continuously monitored using a pulse oximeter (Beurer PO 80, Beurer Healthcare, Germany).

Measurements were obtained at baseline, during apnea and after resumption of breathing.

The primary objective was to quantify changes in intraocular pressure during STA. Secondary objectives included assessment of physiological responses and analysis of their relationship with IOP changes.

• Study Type: Observational
• Enrollment (Actual): 40

Contacts and Locations

Study Locations

• Czechia
  • Olomouc, Czechia, 77900
    • Department of Ophthalmology, University Hospital Olomouc, Olomouc

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adult amateur and professional breath-hold divers

Description

Inclusion Criteria:

• age over 18 years
• breath-hold divers at the amateur or professional level
• signed informed consent

Exclusion Criteria:

• known intraocular hypertension or glaucoma
• refractive error > ±5.00 D
• history of an eye injury
• previous surgery for cataract, strabismus, or pars plana vitrectomy
• corneal disease
• acute eye infection

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Breath-hold divers; Adult amateur and professional breath-hold divers undergoing dry static apnea with repeated assessment of intraocular pressure, blood pressure, heart rate, and oxygen saturation before, during, and after apnea.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in intraocular pressure during dry static apnea	Difference between baseline intraocular pressure and maximal intraocular pressure during apnea	Baseline, during apnea and within 30 and 60 seconds after apnea

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure changes	Changes in systolic, diastolic, and mean arterial pressure during dry static apnea	Before apnea, during apnea and within 60 and 120 seconds after apnea
Heart rate changes	Changes in heart rate during dry static apnea	Baseline, during apnea and within 30 and 60 seconds after apnea
Peripheral oxygen saturation changes	Changes in peripheral oxygen saturation during dry static apnea	Baseline, during apnea and within 30 and 60 seconds after apnea

Collaborators and Investigators

• Sponsor: University Hospital Olomouc
• Collaborators: Palacky University; Lensi Turnov s.r.o.
• Investigators: Principal Investigator: Pavla Potesilova, MD, Lensi Turnov s.r.o.; Study Director: Marta Karhanova, MD, PhD, FEBO, University Hospital Olomouc and Palacky University Olomouc

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2018
• Primary Completion (Actual): March 31, 2019
• Study Completion (Actual): March 31, 2019

Study Registration Dates

• First Submitted: May 17, 2026
• First Submitted That Met QC Criteria: May 17, 2026
• First Posted (Actual): May 22, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 17, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: intraocular pressure; glaucoma; Freediving; breath-hold diving; static apnea
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Eye Diseases; Signs and Symptoms, Respiratory; Ocular Hypertension; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Apnea; Glaucoma
• Other Study ID Numbers: 103/26

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No