Abstract
Background. Blood pulsation affects the results obtained using various medical devices in many different ways. Method. The paper proves the effect of blood pulsation on intraocular pressure measurements. Six measurements for each of the 10 healthy subjects were performed in various phases of blood pulsation. A total of 8400 corneal deformation images were recorded. The results of intraocular pressure measurements were related to the results of heartbeat phases measured with a pulse oximeter placed on the index finger of the subject's left hand. Results. The correlation between the heartbeat phase measured with a pulse oximeter and intraocular pressure is 0.69 ± 0.26 (p < 0.05). The phase shift calculated for the maximum correlation is equal to 60 ± 40° (p < 0.05). When the moment of measuring intraocular pressure with an air-puff tonometer is not synchronized, the changes in IOP for the analysed group of subjects can vary in the range of ±2.31 mmHg (p < 0.3). Conclusions. Blood pulsation has a statistically significant effect on the results of intraocular pressure measurement. For this reason, in modern ophthalmic devices, the measurement should be synchronized with the heartbeat phases. The paper proposes an additional method for synchronizing the time of pressure measurement with the blood pulsation phase.
Highlights
Today, it is difficult to imagine a physician of any specialization without complicated equipment designed to perform different types of measurements in patients
The measurement method proposed by the authors consists of two phases: (i) analysis and processing of images from the Corvis tonometer, which enables us to calculate biomechanical characteristics of the deformed cornea and intraocular pressure (IOP), Table 1: Examples of measured values of features w for a single healthy subject, for one right eye (V = 1), and 6 measurements
The analysis of corneal deformation images is related to an original method involving a series of operations performed on images from the Corvis tonometer
Summary
It is difficult to imagine a physician of any specialization without complicated equipment designed to perform different types of measurements in patients. The impact of this element on measurements is strongly dependent on the anatomical and functional links between the blood pulsation and the measured parameter [1] One of these groups of methods and medical devices includes Diaton transpalpebral tonometer, Dynamic contour tonometer, Goldmann applanation tonometer, and noncontact tonometers: Ocular Response Analyzer (ORA), Corvis ST, for measuring intraocular pressure (IOP), and other additional parameters [2, 3]. The authors of work [6], in particular, showed that the ocular pulse amplitude readings measured with dynamic contour tonometry in healthy subjects were not associated with blood pressure levels nor amplitude It appears that the ocular pulse amplitude is strongly dependent on the time-course of the cardiac contraction. Blood pulsation has a statistically significant effect on the results of intraocular pressure measurement For this reason, in modern ophthalmic devices, the measurement should be synchronized with the heartbeat phases. The paper proposes an additional method for synchronizing the time of pressure measurement with the blood pulsation phase
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
