Biomechanical diagnostics of the cornea

Abstract

Corneal biomechanics has been a hot topic for research in contemporary ophthalmology due to its prospective applications in diagnosis, management, and treatment of several clinical conditions, including glaucoma, elective keratorefractive surgery, and different corneal diseases. The clinical biomechanical investigation has become of great importance in the setting of refractive surgery to identify patients at higher risk of developing iatrogenic ectasia after laser vision correction. This review discusses the latest developments in the detection of corneal ectatic diseases. These developments should be considered in conjunction with multimodal corneal and refractive imaging, including Placido-disk based corneal topography, Scheimpflug corneal tomography, anterior segment tomography, spectral-domain optical coherence tomography (SD-OCT), very-high-frequency ultrasound (VHF-US), ocular biometry, and ocular wavefront measurements. The ocular response analyzer (ORA) and the Corvis ST are non-contact tonometry systems that provide a clinical corneal biomechanical assessment. More recently, Brillouin optical microscopy has been demonstrated to provide in vivo biomechanical measurements. The integration of tomographic and biomechanical data into artificial intelligence techniques has demonstrated the ability to increase the accuracy to detect ectatic disease and characterize the inherent susceptibility for biomechanical failure and ectasia progression, which is a severe complication after laser vision correction.

Correlations between corneal biomechanics and specular microscopy in patient with cataract

“…Numerous studies suggest that corneal hysteresis (CH), an indicator of corneal viscoelasticity, is associated with biomechanical properties of the cornea. Some studies showed that CH may be related to the biomechanical characteristics of peripapillary sclera and lamina cribrosa, as they are embryologically developed from the mesoderm and also because the collagen fibers continue with the collagen fibers from the corneal stroma [ 1 - 8 ].…”

Advances in Imaging Technology of Anterior Segment of the Eye

“…As the Corvis ST is capable of analyzing the whole process of dynamic corneal deformation, it enables calculation of various dynamic corneal response (DCR) parameters [ 3 , 11 , 12 ]. Parameters including “deformation” are calculated without compensating for whole eye movement (WEM), while the parameters including “deflection” compensate for the WEM [ 13 ].…”

“…Initially, the moment during the cornea highest concavity (HC), parameters including radius of corneal curvature (HC radius), time from beginning to the moment of HC (HC time), maximum deformation amplitude (DA), corneal deflection area (HCDeflArea), corneal deflection amplitude (HCDeflAmp), delta arc length of the outer corneal edge between initial state and HC (HCdArclength), and distance between two corneal peaks at HC (peak distance) are measured [ 3 , 9 , 13 ]. The radius of corneal curvature at HC (curvature radius HC) and the maximum value of the integrated inverse of the corneal radius HC (InvRadMax) are also determined [ 3 , 9 , 13 ].…”

Correlation between corneal thickness, keratometry, age, and differential pressure difference in healthy eyes

“…However, most of the available clinical knowledge is related to the biomechanical response to air-puff tonometry. In addition, in vivo characterization of corneal biomechanics is still influenced by the IOP level in spite of significant progress in this field 1 .…”