[Tonometry in change. From indentation and applanation to contour adaptation]

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Devices

Context:

• Intraocular pressure (IOP) monitoring is crucial for diagnosing and managing glaucoma.
• Traditional tonometry methods (applanation, indentation) are indirect and influenced by corneal properties.
• There is a need for more accurate and less invasive IOP measurement techniques.

Purpose:

• To introduce and describe the dynamic contour tonometer (DCT), a novel noninvasive tonometer.
• To explain the working principle of the DCT in directly and continuously measuring IOP.
• To highlight the DCT's reduced dependence on corneal biomechanical properties compared to existing tonometers.

Summary:

• The dynamic contour tonometer (DCT) is a noninvasive device that measures intraocular pressure (IOP) directly and continuously.
• It utilizes a pressure-sensitive tip that induces a natural corneal contour, establishing a force field proportional to IOP.
• A piezoresistive sensor measures IOP precisely and captures time-dependent variations as ocular pulse amplitude (OPA).

Impact:

• The DCT provides a more direct and continuous IOP measurement, potentially improving glaucoma management.
• Its reduced susceptibility to corneal biomechanical variations may lead to more reliable IOP readings.
• The ability to measure ocular pulse amplitude (OPA) offers additional diagnostic information.