Measurements of Corneal Biomechanical Properties Using a Dynamic Scheimpflug Analyzer for Normal Adults in South Korea

The human cornea is affected by the magnitude and velocity of both internal and external forces because the cornea has both static and dynamic resistance components. Considering these natures of the human cornea, many investigators have tried to demonstrate corneal biomechanical properties to understand these characteristics of the cornea. Corneal biomechanical properties are known to influence the accuracy of measurements in intraocular pressure (IOP) and are recognized as important factor to explain the susceptibility of development of glaucomatous damage. Until recently, the only instrument which enabled the in vivo measurements of the ocular biomechanical properties was ocular response analyzer (ORA, Reichert Ophthalmic Instruments, Depew, NY, USA).8 The ORA has been used to assess the biomechanical properties of the cornea according to the dynamic bidirectional applanation process. A dynamic Scheimpflug analyzer (corneal visualization Scheimpflug technology [Corvis ST], OCULUS, Wetzlar, Germany) has been introduced recently and has become a useful instrument for evaluating corneal biomechanical properties. The dynamic Scheimpflug analyzer captures the dynamic process of corneal deformation caused by an air puff using an ultra-high-speed Scheimpflug camera at a rate of up to 4,330 images per second. Until now, well-organized analysis on the normative data of the corneal biomechanical profiles measured with the dynamic Scheimpflug analyzer has not been reported yet. Hence, in the present study, we aim to conduct normative data analysis for the corneal biomechanical properties with the dynamic Scheimpflug analyzer in South Korea.

Inclusion Criteria:

• Only the participants age > 20 years old were included
• have myopia with a spherical equivalent (SE) between 0.00 and -11.00 diopters (D)

Exclusion Criteria:

• Participants were excluded from analyses if they had abnormal eye-related findings except for clinically insignificant senile cataract, previous ocular or intraocular surgery, glaucoma, history of ocular diseases such as glaucoma or age-related macular degeneration, presence of corneal abnormalities such as keratoconus and forme fruste keratoconus, or corneal scarring that would preclude accurate measurements.
• Participants with diabetes mellitus were also excluded, because of the possible effects of the disease on corneal hysteresis.None of the participants were using eye drops, especially anti-IOP agents, which can change the biomechanical properties of the cornea