Exploration of the transfer standard device for rebound tonometer

Abstract

The rebound tonometer is commonly used for measuring intraocular pressure in children and patients with limited mobility due to its small size, portability, and non-invasive nature. In order to ensure the accuracy of its measurements, ISO 8612:2009 "Ophthalmic instruments -Tonometers" mandates that it undergo a clinical human eye comparison test against the Goldmann tonometer, which is considered the "gold standard" for intraocular pressure measurement. Additionally, a transfer standard device is required to assess the consistency of measurements across similar tonometer products. These transfer standard devices, known as simulated eyes, mimic the structure of the human eye to varying degrees of complexity depending on the specific tonometer being tested. This paper presents several solutions for rebound tonometer transfer standard device, including a water column simulated eye, a discrete rubber simulated eye, and a PDMS pressure-adjustable simulated eye.The design principles and pressure regulation of each simulated eye are described. Furthermore, tests are conducted using two different brands of rebound tonometers, and the measurement results are compared. It is important to note that each simulated eye has its own advantages and disadvantages due to its inability to fully replicate all parameters of the human eye. Addressing issues such as traceability and the aging effect of materials is crucial in improving the accuracy and reliability of these simulated eyes.