Corneal hysteresis values in normal Egyptian population

Introduction: Knowledge of the cornea’s biomechanical properties is important for a wide variety of applications within ophthalmology. Corneal biomechanical variations are known to affect the accuracy of intraocular pressure measurements and may be used to identify early corneal disease and may assist in predicting refractive outcomes following corneal refractive surgery. It has also been suggested that corneal biomechanical properties may reflect globe biomechanics, and thus give an indication of the susceptibility of developing glaucomatous damage. Aim of the work: The purpose of this study was to explore the relationships between Ocular Response Analyzergenerated corneal biomechanical characteristics and age in a sample of Egyptian population. Materials and methods: Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured in 195 Egyptians of different age groups. Results: The mean CH value was 10.25 ± 0.12 mmHg (range, 6.5–14.4), and the mean CRF was 10.25 ± 0.15 mmHg (range, 4.9–14.2). The CH value was lower in older eyes, and the difference between the youngest age group (19–40 years) and the oldest age group (40–71 years) was statistically significant (t-test = 0.01). The mean CH in the youngest age group was 11.1 ± 0.14, and that in the oldest age group was 9.8 ± 0.21. The mean CRF in the youngest age group was 10.9 ± 0.18, and that in the oldest age group was 10.1 ± 0.19. Conclusion: This study of corneal biomechanics in normal Egyptian eyes describes the interactions between age and Ocular Response Analyzer metrics. The study reveals that age is significantly associated with CH and CRF. This may help in diagnosis and treatment.