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报告内容摘要：
It is accepted that central corneal thickness (CCT) generates artifact in the measurement of intraocular pressure (IOP) using Goldmann applanation tonometry (GAT). However, theory predicts that corneal elastic properties have a greater impact on measurement error than thickness. In fact, the stiffness of the cornea determines the relationship between CCT and IOP. In stiffer corneas, the relationship is stronger than in softer corneas. Therefore, linear “correction” algorithms based on simple regressions can not only predict the wrong magnitude of correction, but also the wrong direction. In other words, the correction would suggest that the “true” IOP is lower than measured with GAT in a thick, soft cornea, when it may actually be higher. Accurate IOP measurement is critical to diagnosing and monitoring in glaucoma. In addition, it has been reported that low CCT predicts conversion from ocular hypertension to glaucoma and that lower corneal hysteresis, a viscoelastic parameter, is correlated with greater glaucomatous damage. However, the connection between corneal parameters and damage in the back of the eye has never been elucidated. A biomechanical theory will be presented that connects the structures at the front and back of the eye.
In Keratoconus screening, many algorithms exist for the topographic/tomographic detection of “at risk” corneas. These algorithms are based on various combinations of anterior curvature irregularity, thin pachymetry or atypical pachymetry profile, as well as posterior surface elevation anomalies. However, none of these formulas have proven to be superior to all others for differentiating subtle pathologic corneas from those that are normal, in a robust fashion. In fact, iatrogenic ectasia after laser ablative refractive surgery has been reported in cases of adequate corneal thickness, unremarkable curvature patterns, posterior surface within normal limits, and low amount of ablation. It is proposed that the reason for the failure to find a universal screening tool based on corneal geometric features is that curvature, elevation, and pachymetric changes are all secondary signs of keratoconus, and that the primary change is in the biomechanical properties. It is further proposed that the biomechanical modification is focal in nature, rather than a general weakening, and that the focal reduction in elastic modulus precipitates a cycle of biomechanical decompensation that is driven by a disparity in the biomechanical properties. Evidence will be presented in support of this theory, as well as a description of how various interventions such as intrastromal rings, which redistribute the corneal stress, and collagen cross-linking, which modifies the basic structural properties, interrupt this cycle of biomechanical decompensation.

报告人简介：
Cynthia Roberts, Ph.D. completed her B.S. in nursing in 1979 from the University of Iowa. She continued her education in engineering and received an M.S. (1986) in Electrical Engineering with advisor Professor Hsuing Hsu and a Ph.D. (1989) in Biomedical Engineering with advisor J. Fredrick Cornhill, both from The Ohio State University. She joined the faculty at Ohio State in 1989 and is currently the Martha G. and Milton Staub Chair for Research in Ophthalmology, as well as Professor of both Ophthalmology and Biomedical Engineering. Dr. Roberts' primary research interest is in corneal and ocular biomechanics. This includes the influence of corneal properties on accurate assessment of intraocular pressure (IOP), biomechanics of response to refractive surgery, corneal biomechanics of keratoconus, biomechanics of the intraocular pulse, and in vivo measurement of corneal biomechanical properties. She has over 70 publications in refereed journals and 12 book chapters, including the results of collaborations with investigators in Brazil, France, Israel, Italy, Spain, South Africa, Turkey, and the United Kingdom. She has given over 150 invited presentations worldwide, and participated in over 220 abstracts at scientific meetings, as well as given lectures in over 90 courses at medical meetings. Dr. Roberts holds several patents and currently serves on the Editorial Board of two widely read journals in the ophthalmic field, and was Guest Editor of a Special Issue of the Journal of Cataract and Refractive Surgery, which focused on Corneal Biomechanics.