The MiDOC is a precision fluidic pump equipped with flow and pressure sensors that performs tests in the eye to provide real time biometrics and suggestions.
New York Eye and Ear of Mount Sinai
June 2022
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September 2023
Glaucoma is caused by increased intraocular pressure (IOP). This is caused by a greater rate of fluid secretion than drainage in the eye. In glaucoma surgery, stents or other forms of drainage pathways are often added to bring the patients IOP back to normal levels. Without the MiDOC however, this is done in a very primitive way.
The eye is probed with the surgeon's finger to "feel the IOP", Opthalmic surgeons are trained to detect a pressure of around 20 mmHg just by poking an eye with their finger. The number and size of stents is then estimated based on the pressure that the surgeon felt.
Unsurprisingly, this state-of-the-art finger poking method typically requires the patient to revist the hospital for checkups over the next few days to determine how accurately the surgeon guessed. If the IOP is still high an additional stent may be added, or the drainage pathway may be enlarged, otherwise if the IOP is too low, it may be stitched closed.
The MiDOC takes the guess work out of the glaucoma surgery procedure. It uses a precision fluidic pump in conjunction with very sensitive flow and pressure sensors to determine the physical characteristics of the eye. Two important characteristics are ocular compliance, and ocular outflow. These two metrics can be compared to the capacitance and current drain of an LC circuit. Just like an LC circuit, if step impulses at various known voltages (pressures) are performed while taking voltage (pressure) and flow (current) measurements during the decay curve, the capacitance and current drain can be calculated. This alone is enough to calculate the required outflow stent to maintain a stable postoperative IOP. The addition of AI data analysis paired with an intuitive UI allows for a slew of other biometric information during the surgery as well.
To make this work, very accurate flow sensors are required at high sampling rates. The PCB I designed below supports up to 4 pressure sensors (for differential measurements) and 1 flow sensor. Operating at a sampling rate of 2000 samples per second, this device is capable of detecting footsteps across the room by measuring flow in a stagnant cup of water...
