Ralation Between Cardiorespiratory Fitness and Mean Corrected Intraocular Pressure

Cardiorespiratory Fitness and Mean Corrected Intraocular Pressure: A Cross-Sectional Study in a Normotensive Health Check-up Population

Objective: To investigate the association between cardiorespiratory fitness and mean corrected intraocular pressure (IOP) in a normotensive health check-up population, and to evaluate potential differences across age and sex strata.

Methods: This cross-sectional study consecutively enrolled adults aged 18-70 years who completed cardiorespiratory fitness testing and ophthalmologic examinations at the Health Management Center of Sichuan Provincial People's Hospital between July 1, 2019 and December 31, 2025. Individuals were excluded if they had a history of glaucoma, ocular diseases interfering with IOP measurement, systemic diseases or medications affecting IOP, contraindications to fitness testing, or abnormal blood pressure. A final sample of 2,921 normotensive individuals was included. Cardiorespiratory fitness was assessed by estimated maximal oxygen uptake (VO₂max). After age- and sex-stratified grouping, low cardiorespiratory fitness was used as the reference, and the remainder were defined as the moderate-to-high cardiorespiratory fitness group. The primary outcome was the mean corrected IOP of both eyes. Multiple imputation, multivariable linear regression, and age- and sex-stratified analyses were used to evaluate the association.

Study Overview

• Status: Completed
• Conditions: Cardiorespiratory Fitness; Eye Disorders
• Intervention / Treatment: Other: Mean corrected intraocular pressure (IOP) of both eyes

• Study Type: Observational
• Enrollment (Actual): 2921

Contacts and Locations

Study Locations

• China
  • Sichuan
    • Chengdu, Sichuan, China, 610000
      • Sichuan Provinvial People's HSichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital（ SAMS&SPPH，Affiliated Hospital of UESTC）ospital

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

This single-center cross-sectional study enrolled adults who underwent health check-ups, completed standardized cardiorespiratory fitness testing, and underwent ophthalmologic examinations at the Health Management Center of Sichuan Provincial People's Hospital from July 1, 2019 to December 31, 2025. After applying the predefined inclusion and exclusion criteria, 2,921 normotensive adults were included in the final analysis.

Description

Inclusion Criteria:

1. Age 18-70 years;
2. Ability to complete standardized cardiorespiratory fitness testing and provide valid data; and
3. Ability to cooperate with a comprehensive ophthalmologic examination.

Exclusion Criteria:

1. Any history of glaucoma or ocular hypertension, or detection of glaucoma suspect signs such as cup-to-disc ratio ≥0.7, interocular cup-to-disc ratio asymmetry >0.2, or localized retinal nerve fiber layer defects;
2. Ocular diseases or surgical history affecting IOP measurement or optic nerve head assessment, such as corneal disease, uveitis, intraocular surgery, high myopia (spherical equivalent ≤ -6.00 D), or other optic nerve/retinal diseases;
3. Systemic diseases that could significantly interfere with IOP, optic nerve blood supply, or cardiorespiratory function, such as uncontrolled diabetes mellitus, severe cardiovascular or cerebrovascular disease, or chronic obstructive pulmonary disease;
4. Current use of topical or systemic medications known to affect IOP, including IOP-lowering eyedrops, systemic beta-blockers, or glucocorticoids;
5. Contraindications to cardiorespiratory fitness testing, such as severe musculoskeletal disorders or uncontrolled arrhythmias;
6. A documented history of hypertension, current use of antihypertensive medications, or abnormal blood pressure on a single measurement that did not normalize on re-examination (systolic blood pressure [SBP] ≥140 mmHg or diastolic blood pressure [DBP] ≥90 mmHg); and
7. Missing key study variables that precluded further analysis.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
low cardiorespiratory fitness; Cardiorespiratory fitness levels were classified based on age- and sex-stratified percentiles of VO₂max in the present study sample. VO₂max ≤ the 25th percentile for the same age group and sex was defined as low cardiorespiratory fitness.	Other: Mean corrected intraocular pressure (IOP) of both eyes; Intraocular pressure (IOP) was measured in both eyes using a non-contact tonometer (CT-1P, Topcon Corporation, Tokyo, Japan). The corrected IOP was automatically calculated by the device's built-in algorithm based on central corneal thickness. In Chinese healthy adults, corneal thickness is significantly associated with sex and age, which has important clinical implications for the correction of IOP measurements. To minimize the influence of diurnal fluctuation on IOP measurements, all IOP assessments were uniformly scheduled between 7:30 AM and 11:00 AM. Two measurements were taken for each eye and the average was recorded. The mean corrected IOP, defined as the average of the corrected IOP values of both eyes, was used as the primary outcome measure in this study.
Moderate-to-high cardiorespiratory fitness; The remainder were defined as moderate-to-high cardiorespiratory fitness.	Other: Mean corrected intraocular pressure (IOP) of both eyes; Intraocular pressure (IOP) was measured in both eyes using a non-contact tonometer (CT-1P, Topcon Corporation, Tokyo, Japan). The corrected IOP was automatically calculated by the device's built-in algorithm based on central corneal thickness. In Chinese healthy adults, corneal thickness is significantly associated with sex and age, which has important clinical implications for the correction of IOP measurements. To minimize the influence of diurnal fluctuation on IOP measurements, all IOP assessments were uniformly scheduled between 7:30 AM and 11:00 AM. Two measurements were taken for each eye and the average was recorded. The mean corrected IOP, defined as the average of the corrected IOP values of both eyes, was used as the primary outcome measure in this study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Mean corrected intraocular pressure (IOP) of both eyes	same day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ocular hypertension	IOP > 21 mmHg in one eye	same day 1

Collaborators and Investigators

• Sponsor: Sichuan Academy of Medical Sciences

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2025
• Primary Completion (Actual): December 31, 2025
• Study Completion (Actual): March 1, 2026

Study Registration Dates

• First Submitted: June 24, 2026
• First Submitted That Met QC Criteria: June 24, 2026
• First Posted (Actual): June 30, 2026

Study Record Updates

• Last Update Posted (Actual): June 30, 2026
• Last Update Submitted That Met QC Criteria: June 24, 2026
• Last Verified: July 1, 2019

More Information

Terms related to this study

• Keywords: cardiorespiratory fitness; maximal oxygen uptake; cross-sectional study; normal blood pressure; mean adjusted intraocular pressure
• Additional Relevant MeSH Terms: Eye Diseases
• Other Study ID Numbers: SichuanAMS-2026-280; 2023QN15 (Other Grant/Funding Number: Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital（ SAMS&SPPH，Affiliated Hospital of UESTC）)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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