Related Experiment Video
Updated: Apr 25, 2026
Comparison of Agreement and Accuracy using Binocular Wavefront Optometer with Autorefractor and Phoropter
Published on: September 16, 2025
Corneal resistance factor and corneal hysteresis in a 6- to 18-year-old population
Hassan Hashemi1, Ebrahim Jafarzadehpur1, Shiva Mehravaran1
1From the Noor Ophthalmology Research Center (Hashemi, Jafarzadehpur, Mehravaran), Noor Eye Hospital, and the Department of Optometry (Jafarzadehpur), Iran University of Medical Sciences, the Department of Epidemiology (Khabazkhoob) Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, the Refractive Errors Research Center (Yekta, Ostadimoghaddam) and the Department of Optometry (Yekta, Ostadimoghaddam), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, and the Dezful University of Medical Sciences (Norouzirad), Dezful, Iran.
Purpose:
To determine the distribution and normal range of the corneal resistance factor (CRF) and corneal hysteresis (CH) in the 6- to 18-year age range and their relationship with biometric components.
Setting:
Dezful, Iran.
Design:
Cross-sectional study.
Methods:
This study of Dezful school children used a multistage, stratified, cluster approach sampling. All students had examinations for biometry, noncycloplegic refraction, and corneal biomechanical properties; the examinations were performed in the same order in all cases.
Results:
Of the 864 selected students, 683 participated in the study. The mean CRF and CH was 11.74 mm Hg±1.77 (SD) (95% confidence interval [CI], 11.58-11.89) and 11.49±1.91 mm Hg (95% CI, 11.33-11.65), respectively. In a linear multiple regression model, the CRF significantly correlated with female sex (β coefficient=0.488, P=.013), central corneal thickness (CCT) (β coefficient=.034, P=.001), and keratometry (β-coefficient=0.157, P=.003) and CH significantly correlated with CCT (β coefficient=0.025, P<.001), axial length (β coefficient=-0.303, P=.011), and keratometry (β coefficient=0.11, P=.043). Each year increase in age was associated with a 42-unit decrease in the peak 1 area (P=.003).
Conclusions:
The distribution of CRF and CH in an Iranian population was symmetrical and bell shaped. However, the CRF did not have a normal distribution. The mean CRF and CH were higher than those reported in almost all previous studies.
Financial Disclosure:
No author has a financial or proprietary interest in any material or method mentioned.
