Abstract
This study proposes an eyeball vibration-type non-contact tonometer using a Point-focus-type Parametric Speaker (PPS). In this method, the cornea is vibrated by PPS using an ultrasonic carrier wave that can cause a low frequency oscillation in a small space. Further, by vibrating the cornea using signals below the low frequency range, the proposed device does not emit any sound to the surroundings. It had been revealed that the amplitude of the vibration to happen on corea decreases with the increase of the intraocular pressure experimentally. However, it was not possible to estimate an accurate intraocular pressure from the cornea vibration; because, a correlation between the amplitude os a cornea vibration and the intraocular pressure amplitudes was low. This problem occurred due to an insufficient investigation of the characteristics of PPS in the previous study. In this paper, the results of measuring an exact sound pressure distribution of PPS are reported.
