Non-Invasive Real-Time Analyte Monitoring Summary

Non-Invasive Real-Time Monitoring

PI: Mark Borchert, M.D. is an Associate Professor of Clinical Ophthalmology and Neurology at the USC Keck School of Medicine. He is currently the Head of the Division of Ophthalmology at Children's Hospital Los Angeles.  James Lambert, Ph.D. is an electrical engineer and has been with JPL for 20 years and for the last five years has served as the Technical Group Supervisor of the Intelligent Instrument and Systems Technology Group.  In addition, he has an appointment as Associate Professor of Ophthalmology in the Keck School of Medicine at USC.

Drs. Borchert and Lambert have successfully developed a collection of diagnostic medical devices based on optical imaging technology:

1. Non-invasive glucose monitor
2. Non-invasive identification and measurement of selected substances or toxins in the human body
3. Non-invasive intracranial pressure monitor
4. Visual acuity and amblyopia screening device
5. Non-invasive measurement of macular pigments.

Non-Invasive Glucose Monitor

Blood glucose monitoring is an important aspect of the management of diabetes, however, current technologies rely on measuring glucose in blood obtained either from a blood draw, or by pricking the skin with a lancet.  Since diabetics may need to monitor their blood glucose many times during each day, there is a need to move away from invasive methods.  The Pis have developed a non-invasive glucose monitoring device that accurately measures glucose in the aqueous humor of the eye, without contacting the eye, using Raman spectroscopy technology - glucose levels in the aqueous humor are highly correlated with blood glucose levels.

This technology is currently entering phase I trials.

Non-invasive Identification and Measurement of Selected Substances or Toxins in the Human Body
Our glucose monitoring device can be utilized for non-invasive measurement of drug levels in the aqueous humor.  This has significant potential as numerous drug compounds can be detected and accurately measured that have been difficult to achieve.  Two compounds that have been accurately measured both in vitro and in vivo using this device are ethanol and amphotericin B (AmB), an anti-fungal agent.  As well as the medical needs for assessing such substances, non-invasively monitoring blood ethanol may have utility to law enforcement agencies.

Non-Invasive Intracranial Pressure Monitor

Intracranial pressure (ICP) is an important indicator of CNS disease.  However, measuring ICP requires lumbar puncture, which can cause herniation of the brain stem in patients with increased ICP.  Thus, the PIs have developed a device that uses intraocular optical coherence tomography (OCT) to non–invasively measure intracranial pressure.  The underlying technology for this device is based on nerve axon swelling in papilledema, a condition in which increased pressure around the brain causes the optic nerve to swell where it enters the eye, being related to the difference between the ICP and the intraocular pressure (IOP).  This difference can be measured with OCT that accurately measures swelling within the nerve fiber layer of the retina.

Measurement of Macular Pigments

Macular degeneration (MD) is one of the most common causes of adult onset blindness.  Accurately monitoring macular pigment (MP) in the retina is an essential component to diagnosing MD and monitoring its progression.  The PIs have developed a novel, non-invasive, optical approach for in vivo measurement of MP levels based on a new approach using resonance Raman scattering.  Argon laser light (488 nm) is used to illuminate carotenoids and increase detection levels up to 100,000 times, greatly facilitating detection of characteristic MP, even at very low concentrations.

Visual Acuity and Amblyopia Screening Device

We are applying eye-tracking technology in new ways in an effort to develop a standard quick and efficient method of testing visual acuity in pre-verbal children.  Through this new application of eye-tracking technology to accurately test visual acuity in young children, abnormalities in vision will be detected early, allowing measures to be taken to effectively correct the problem.

This devise uses automatic eye tracking to mimic the Acuity Card procedure by ophthalmologists.  It is easy to run (requiring very little training), is completely objective and has a test time of less than 3 minutes.  The device is being used at Childrens Hospital Los Angeles to test visual acuity in children, while helping to screen for amblyopia (“lazy eye”).