Reproducibility of measurements with a new slit lamp-mounted ocular blood flow tonograph

Purpose: To assess the reliability of measurements of intraocular pressure (IOP), pulse amplitude (PA), and pulsatile: ocular blood flow (POBF) and the validity of measurements of IOP with a new ocular blood flow tonograph. Methods: Intraocular pressure pulse was assessed with pneumatic tonometry. In this study, we used the OBF Labs ocular blood flow tonograph with two different pneumatic probes, a modified Langham probe and a newly developed probe. One ophthalmologist compared two machines, first with the modified Langham probe and secondly with the newly developed probe (40 volunteers), Additionally, two ophthalmologists performed measurements on different days and in different sequence (34 volunteers). Furthermore, results of IOP measurements performed with this tonograph were compared to those of Goldmann applanation tonometry (213 volunteers). Results: Using the modified Langham probe, POBF and PA were associated with the machine used for the test. However, using the newly developed pobe, no relevant or statistically significant differences were found for any variables, and reliability coefficients were between 0.70 and 0,90. Linear regression analysis of the Goldmann applanation tonometer on the measurements of IOP with the tonograph showed a regression coefficient of 0.765. Conclusions: Results of measurements performed with this ocular blood flow tonograph and the newly developed probe are expected to be reliable and comparable.