• August 20, 2014

    A microfluidic sensor embedded within an implantable lens could help monitor eye pressure in glaucoma patients. High pressure can cause blindness. The sensor is a microfluidic channel connected on one side to the eye fluid and to a tiny gas reservoir on the other. The lens’ arms stabilize the lens in place within the eye.

    A new lens-mounted microfluidic sensor can measure fluid pressure inside the eye and provide a readout with a smartphone camera. The simple, low-cost device could make it much easier for doctors to diagnose blindness-causing glaucoma. It could also give glaucoma patients a 24-hour home-based monitoring test similar to the glucose monitors available for diabetics.

    Glaucoma affects 65 million people and is the second-most common cause of blindness in the world. One of its main risk factors is an increase in the eyeball fluid pressure, which can build up enough to damage the optic nerve. Eye doctors today measure this intraocular pressure using a tonometer, but the test is not always accurate.

    The new sensor consists of an airtight 50 µm-channel that runs around most of the periphery of a lens that is used for cataract surgery. On one side it ends in a tiny gas reservoir, while on the other it connects to the aqueous eyeball fluid. A doctor would surgically implant the lens into a patient’s eye.

    When the microchannel is connected into the eye chamber, pressure drives the intraocular fluid into the microchannel, compressing the reservoir gas until the gas pressure and liquid pressure reach equilibrium. An increase or decrease in the intraocular pressure forces the fluid to move toward or away from the gas reservoir. A smartphone camera equipped with an optical adapter and image analysis software can be used to accurately detect the position of the liquid. The optical adapter positions the camera in front of the pupil and shades the eye, causing the pupil to dilate and reveal the sensor.

     of Bar Ilan University in RamatGan, Israel and of Stanford University and their colleagues reported the new sensor in the journal 

    The researchers first tested and calibrated the sensor in a pressure chamber by simulating changes in intraocular pressure. They found that the movement of the liquid inside the microchannel was linear to pressure changes and sensitive to pressure fluctuations as small as 1 mm Hg. Normal intraocular pressure ranges between 10-21 mm Hg, but can increase by 8 mm Hg when a person is lying down. The researchers also tested the implant in surgically removed pig eyes, where it also showed a detection limit of 1 mm Hg.

    Other eye pressure sensors exist. University of Michigan researchers have developed, for instance, . And Swiss medical device-maker  already has a  in which a piezoelectric platinum ring changes resistance when the eyeball inflates. But these approaches rely on wireless data telemetry, which requires bulky antenna and power sources.

    The optical readout on the new microfluidic sensor could be easier to use, though it does have its own limitations. Reading the fluid position through a hazy cornea, which can happen in glaucoma patients, could be difficult, for instance. And gas could leak out of the sensor walls, making readings inaccurate. Nevertheless, the researchers say that their experimental results suggest a 10-year device life.


    No comments

    Be the first one to leave a comment.

    Post a Comment



    Latest Posts

    Latest Video



    Artificial Intelligence Diagnoses Heart Murmurs Better Than Expert Cardiologists

    SOURCE Eko’s heart murmur detection algorithm outperformed four out of five cardiologists for the detection of heart murmurs in a recent clinical study. The algorithm…

    UCI researchers uncover evidence of restored vision in rats following cell transplant

    Irvine, Calif. – November 5, 2018 – Researchers from the University of California, Irvine School of Medicine, have discovered that neurons located in the vision centers…

    Artificial intelligence controls quantum computers

    SOURCE (Nanowerk News) Quantum computers could solve complex tasks that are beyond the capabilities of conventional computers. However, the quantum states are extremely sensitive to…

    Bad Oral Habits: How to Get Rid of These Awful Habits?

    You are practicing excellent dental care: brushing your teeth, floss regularly and visiting your dentist two times a year for cleanings and checkups. These things…

    Change the World: How to Get Your Medical Invention in Hospitals Today

    Medical advancements have completely changed the world. We now live longer, better lives, meaning our legacies and impact on this planet are greater than ever…

    How to Support a Loved One Living with Dementia

    If you are caring for a loved one who is living with dementia, you will want to provide them with the help and support they…