Intraocular Pressure During Static Apnea

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

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT07604428

Enrollment

Registered

2026-05-22

Start date

2018-01-01

Completion date

2019-03-31

Last updated

2026-05-22

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Apnea, Glaucoma, Intraocular Pressure

Keywords

Freediving, breath-hold diving, static apnea, intraocular pressure, glaucoma

Brief summary

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.

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.

Interventions

None listed

Study design

Observational model

COHORT

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Yes

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

Design outcomes

Primary

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

Secondary

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

Countries

Czechia

Contacts

PRINCIPAL_INVESTIGATORPavla Potesilova, MD

Lensi Turnov s.r.o.

STUDY_DIRECTORMarta Karhanova, MD, PhD, FEBO

University Hospital Olomouc and Palacky University Olomouc

Outcome results