Lein is enhancing its measurement system to analyse non-invasively the absorption and distribution of pharmaceutical drugs within the human body without the need to draw blood. This is achieved by using a second channel in our confocal system that can track the diffusion of a drug using its optical fingerprint.


Diagnosing Physiological Conditions Via The Eye

Lein is applying its experience in optics, ophthalmology and medical devices to develop new technologies that can examine physical attributes of the body. The primary advantage is that the method used is non-invasive and there is no need to draw blood to take a measurement - so there is no pain for the patient and greater ease of use for the point of care professional.


Lein’s technology works first by shining a low power beam of light into the eye, then analyses the reflected signal. This gives not only direct information on the structure of the eye but also on the health of the body. The eye, often called the "window to the soul", is in practice the window to your health.


Durham University Collaboration

Lein has put together a collaboration with Durham University, who have expertise in optical measurements on the body, Strathclyde University, who have expertise in pharmacokinetics via the eye, and a large US pharmaceutical company who wish to use the technology to gain a better understanding of their drug’s performance.


An EPSRC CASE award studentship was set up at Durham University in 2009 with the aim of adapting Lein’s technology to the detection and monitoring of pharmaceutical drugs non-invasively, in the anterior segment of the eye. This work is now almost complete.


The team at Durham University have built an instrument capable of tracking the diffusion of fluorescent drugs in the eye. The instrument is based on a confocal fluorescent scanning microscope and is a design adapted from one of Lein's instruments.


The focus of a laser (λ = 405nm) is scanned through the anterior chamber along the optical axis. Fluorescent light within a specific wavelength range excited by the laser is returned from the eye and recorded and analysed by the instrument.


The instrument, which has already been evaluated both in-vitro and ex in-vivo, is extremely sensitive and can detect Fluorescein concentrations lower than 2 nmol/L. It is also has a data acquisition rate of 2 scans per second. The in vitro tests have demonstrated the ability of the meter to track the diffusion of a drop of Fluorescein with an axial resolution of 124 µm. The next step is to evaluate the instrument’s performance on human volunteers.



Tracking Opthalmic Drugs in the Eye Using Confocal Fluorescence Microscopy


Kim K. Buttenschön, John M. Girkin and Daniel J. Daly,
Proc.SPIE 8214, Advanced Biomedical and Clinical Diagnostic Systems X, 821403
(February 9, 2012); doi:10.1117/12.906
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