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Ocular and General Determinants of Intraocular Pressure: The Two-Continent Eye Study
Jost B Jonas1,2,3,4,5,6,7, Rahul A Jonas8,9, Mukharram M Bikbov10
1Rothschild Foundation Hospital, Paris, France.
Investigative Ophthalmology & Visual Science
|February 5, 2026
Summary
Intraocular pressure (IOP) readings are influenced by various factors, including corneal curvature. Adjusting IOP measurements based on these factors can significantly alter the perceived normal range, impacting glaucoma diagnosis.
Area of Science:
- Ophthalmology
- Public Health
- Biometry
Background:
- Intraocular pressure (IOP) is a critical metric in diagnosing and managing glaucoma.
- Accurate IOP measurement is essential, but readings can be influenced by various ocular and systemic factors.
- Population-based studies provide valuable insights into the prevalence and determinants of ocular conditions across diverse demographics.
Purpose of the Study:
- To assess the associations of various factors with intraocular pressure (IOP) readings.
- To investigate the impact of these associations on IOP measurement accuracy.
- To evaluate the effectiveness of correcting IOP readings based on identified influencing factors.
Main Methods:
- Utilized population-based data from studies in Russia, China, and India, including the Beijing Eye Study (BES), Ural Eye and Medical Study (UEMS), Ural Very Old Study (UVOS), Ural Children Eye Study (UCES), and Central India Eye and Medical Study (CIEMS).
- Included a total of 35,199 eyes from 17,977 individuals aged 6 to 100 years.
- Employed pneumo-tonometry or applanation tonometry for IOP measurements and statistical analyses to identify associations and validate corrected IOP values.
Main Results:
- Higher IOP readings were associated with younger age, female sex, rural residence, diabetes mellitus, higher systolic blood pressure, thicker central corneal thickness (CCT), steeper cornea, longer axial length, and pseudoexfoliation.
- Corrected IOP values showed strong correlations with external validation groups (UEMS: r2 = 0.85; CIEMS: r2 = 0.80).
- Bland-Altman analysis revealed mean biases of 0.80 mm Hg and 1.51 mm Hg for UEMS and CIEMS, respectively, with significant interindividual variation in corrected IOP.
Conclusions:
- Corneal curvature radius emerged as a primary ocular determinant influencing IOP readings, alongside numerous other ocular and systemic factors.
- Correction of measured IOP readings based on identified associations led to substantial interindividual variations in the upper limit of the "normal" IOP range.
- These findings highlight the complexity of IOP measurement and the need for individualized assessment in clinical practice.
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