Preliminary investigations with a new indentation type tonometer

A new type of tonometer is being developed and tested at the University of New Hampshire (UNH) that will allow not only ocular tonometric recordings but a vast variety of tonometric measurements. The UNH tonometer (UNHT) set in the ocular mode to measure intraocular pressure (IOP) in humans was tested against a Goldmann applanation tonometer. Eyes were simulated with balloons filled with saline and of the same radius of curvature as the human eye. Three-quarters of the balloon was covered with an inelastic membrane that force the remaining quarter area to simulate the cornea. Saline was introduced into the simulated eyes via hypodermic needle. Measurements were taken with the Goldmann tonometer (GT) and then the UNHT as saline was introduced into the simulated eye at 5-mmHg increments from 10-mmHg to 40-mmHg. Tests comparing the UNHT in the ocular mode to the GT indicate that the UNHT is linear but follows a regression formula of UNHT=8.48+0.446*GT