BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Giuseppe Tomassetti (University of Roma Tre) DTSTART:20240318T144000Z DTEND:20240318T161000Z DTSTAMP:20260405T174543Z UID:NSCM/142 DESCRIPTION:Title: A mechanical model of ocular bulb vibrations and implications for acoustic tonometry\nby Giuseppe Tomassetti (University of Roma Tre) as part of Nečas Seminar on Continuum Mechanics\n\nLecture held in Room K3\, Facult y of Mathematics and Physics\, Charles University\, Sokolovská 83 Prague 8..\n\nAbstract\nWe propose a comprehensive mechanical model of ocular bu lb vibrations and discuss its implications for acoustic tonometry. The mod el describes the eye wall as a spherical\, pre-stressed elastic shell cont aining a viscoelastic material and accounts for the interaction between th e elastic corneoscleral shell and the viscoelastic vitreous humor. We inve stigate the natural frequencies of the system and the corresponding vibrat ion modes\, expanding the solution in terms of scalar and vector spherical harmonics. From a quantitative point of view\, our findings reveal that t he eyebulb vibration frequencies significantly depend on IOP. This depende ncy has two origins: "geometric" stiffening\, due to an increase of the pr e-stress\, and "material" stiffening\, due to the nonlinearity of the stre ss-strain curve of the sclera. The model shows that the second effect is b y far dominant. We also find that the oscillation frequencies depend on oc ular rigidity\, but this dependency is important only at relatively large values of IOP. Thus close to physiological conditions\, IOP is the main de terminant of ocular vibration frequencies. The vitreous rheological proper ties are found to mostly influence vibration damping. This study contribut es to the understanding of the mechanical behavior of the eye under dynami c conditions and thus has implications for non-contact intraocular pressur e measurement techniques\, such as acoustic tonometry. The model can also be relevant for other ocular pathological conditions\, such as traumatic r etinal detachment\, which are believed to be influenced by the dynamic beh avior of the eye.\n LOCATION:https://researchseminars.org/talk/NSCM/142/ END:VEVENT END:VCALENDAR