Non-Contact Intraocular Pressure Measurement Method using Relation between Deformed Cornea and Reflected Pneumatic Pressure

Deviating from existing non-contact type of intraocular pressure measurement method, which utilizes pneumatic and optical modules, this paper proposed new measurement method using pneumatic module only. In proposed method, cornea is deformed by pneumatic pressure, and pneumatic pressure reflected on cornea is measured by focus-type hollow nozzle. As a simulation results to verify proposed method, reflected pneumatic pressure decreased as the measured distance increased and the intraocular pressure increased. As an experiment results, the ratio of reflected pneumatic pressure for intraocular pressure of 10, and 50 mmHg at a measurement distance of 3 mm was about 0.21% and 0.16%, and at a measurement distance of 5 mm was about 0.21% and 0.16%, respectively. When intraocular pressure was high, low reflected pneumatic pressure was output, and simulation and experimental results showed same tendency. As a related result with the shape of the deformed cornea, cornea was largely deformed when intraocular pressure was low, and the injected pneumatic pressure was concentrated more within space formed by deformed cornea. The concentrated pneumatic pressure flowed into nozzle, and large amount of reflected pneumatic pressure was collected. The proposed method was investigated through both simulation and experimentally, and possibility was confirmed.