New method for remote and repeatable monitoring of intraocular pressure variations

Abstract

We present initial steps toward a new measurement device enabling high-precision, noncontact remote and repeatable monitoring of intraocular pressure (IOP)-based on an innovative measurement principle. Using only a camera and a laser source, the device measures IOP by tracking the secondary speckle pattern trajectories produced by the reflection of an illuminating laser beam from the iris or the sclera. The device was tested on rabbit eyes using two different methods to modify IOP: via an infusion bag and via mechanical pressure. In both cases, the eyes were stimulated with increasing and decreasing ramps of the IOP. As IOP variations changed the speckle distributions reflected back from the eye, data were recorded under various optical configurations to define and optimize the best experimental configuration for the IOP extraction. The association between the data provided by our proposed device and that resulting from controlled modification of the IOP was assessed, revealing high correlation (R2=0.98) and sensitivity and providing a high-precision measurement (5% estimated error) for the best experimental configuration. Future steps will be directed toward applying the proposed measurement principle in clinical trials for monitoring IOP with human subjects.

Ambulatory 24-h intraocular pressure monitoring in the management of glaucoma

“…In addition to the CLS, several other noninvasive devices are currently being developed [47,48]. They are currently at the experimental stage and are not commercially available.…”

Glaucoma, the disease that never sleeps

“…Documenting relative changes of IOP related events and their timing may yet prove to be of similar importance than absolute IOP levels. In addition to the CLS, other non-invasive devices are currently being developed (14,15) . In 2011, an implantable telemetric pressure transducer system to continuously monitor IOP was tested in non-human primates and shown to provide accurate measurements (16) .…”

Intraocular pressure remote photonic biomonitoring based on temporally encoded external sound wave stimulation

“…In the current research, we used the above technology for semicontinuous noninvasive IOP measurement. Following presentation of the basic principle, 54,55 a technique using sounddriven corneal vibration was introduced in the current study. The existing method for detecting IOP based on a sound wave for corneal oscillation 45,56,57 was used by us before while the reflected secondary speckle patterns variations were analyzed.…”

“…It was found that IOP is correlated to the vibration amplitude; however, the measured amplitude of the vibration depends on the position of the laser beam on the corneal surface. 54,55 To minimize such constrain, we found it necessary to introduce physical parameters of the corneal vibration giving more consistent results. For this purpose, the corneal surface was agitated by sound wave and dumped oscillation of the cornea was evaluated as a function of IOP.…”