Corneal Biomechanical Assessment with Ultra-High-Speed Scheimpflug Imaging During Non-Contact Tonometry: A Prospective Review

Abstract

Background In recent years, increasing interest has arisen in the application of data from corneal biomechanics in many areas of ophthalmology, particularly to assist in the detection of early corneal ectasia or ectasia susceptibility, to predict corneal response to surgical or therapeutic interventions and in glaucoma management. Technology has evolved and, recently, the Scheimpflug principle was associated with a non-contact air-puff tonometer, allowing a thorough analysis of corneal biomechanics and a biomechanically corrected intraocular pressure assessment, opening up new perspectives both in ophthalmology and in other medical areas. Data from corneal biomechanics assessment are being integrated in artificial intelligence models in order to increase its value in clinical practice. Objective To review the state of the art in the field of corneal biomechanics assessment with special emphasis to the technology based on ultra-high-speed Scheimpflug imaging during non-contact tonometry. Summary A meticulous literature review was performed until the present day. We used 136 published manuscripts as our references. Both information from healthy individuals and descriptions of possible associations with systemic diseases are described. Additionally, it exposed information regarding several fields of ocular pathology, from cornea and ocular surface through areas of refractive surgery and glaucoma until vascular and structural diseases of the chorioretinal unit.

Assessment of corneal biomechanics in anisometropia using Scheimpflug technology

“…Age is one of the important factors in corneal biomechanics. Similar to previous studies (Celebi et al, 2018;Eliasy et al, 2019;Liu et al, 2020;Baptista et al, 2021), several Corvis ST parameters were correlated with age, indicating the cornea became stiffer with increasing age (Table 1 and Table 2).…”

“…Similar to previous studies ( Celebi et al, 2018 ; Eliasy et al, 2019 ; Liu et al, 2020 ; Baptista et al, 2021 ), several Corvis ST parameters were correlated with age, indicating the cornea became stiffer with increasing age ( Table 1 and Table 2 ). More glycation-induced ( Kling and Hafezi, 2017 ) and sun-related ( Baptista et al, 2021 ) cross-linking contribute to this change. However, there was no significant correlation between SSI and age ( Table 1 and Table 2 ).…”

“…More glycation-induced (Kling and Hafezi, 2017) and sunrelated (Baptista et al, 2021) cross-linking contribute to this change. However, there was no significant correlation between SSI and age (Table 1 and Table 2).…”

“…Mechanical factors may play important roles in anisometropia ( Vincent et al, 2014 ). The cornea, a crucial part of the ocular optical system, has complex biomechanical properties such as anisotropy, nonlinearity, and viscoelasticity ( Esporcatte et al, 2020 ; Baptista et al, 2021 ; Chong and Dupps, 2021 ).…”

“…Previous studies using the ocular response analyzer (ORA) found that more myopic eyes had lower corneal hysteresis (CH) compared with the fellow eyes in high anisometropia, indicating more myopic eyes had weaker corneal biomechanical properties ( Xu et al, 2010 ). ORA, the first clinical device to measure corneal biomechanics has some limitations, for example, the real meaning of ORA parameters is not clear and CH does not have a direct relationship with stiffness parameters (such as Young’s modulus) ( Baptista et al, 2021 ). The corneal visualization Scheimpflug technology device (Corvis ST), using dynamic Scheimpflug imaging technology can display the dynamic process of corneal deformation under external force in real-time ( Esporcatte et al, 2020 ), maybe a better choice to evaluate corneal biomechanics in vivo ( Pinero and Alcon, 2015 ; Jędzierowska and Koprowski, 2019 ).…”