Purchase this article with an account.
Shuo Zhang, Roel J Erckens, Frans HM Jongsma, John de Brabander, Carroll Webers, Tos TJM Berendschot; A new Raman spectrometer device for non-invasive determination of the molecular composition of the living eye.. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3112.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To develop a new method for non-invasive analysis of physiology and pathology in the eye based on Raman spectroscopy, with which the anterior eye chamber can be optically sampled without direct illumination of the retina. To develop a new method for non-invasive analysis of physiology and pathology in the eye based on Raman spectroscopy, with which the anterior eye chamber can be optically sampled without direct illumination of the retina.
We designed a dark field device to exclude the laser shining directly on the retina. A confocal Raman spectrometer (Model 2500, River Diagnostics®) was employed as signal acquiring system, and a 30 mW, 785 nm and a 20 mw, 671nm diode laser were used as light sources. The device was designed and optimized using ray-tracing software (ZEMAX, Radiant Zemax, Redmond, WA). For proof of principle we used an artificial eye model, combining a sclera lens and a cuvette, as well as enucleated rabbit eyes.
Ray tracing showed that the laser light could focus at 1.24 mm depth under the top surface of cornea. Peaks of ethanol at 884cm-1 and 2930 cm-1 could clearly be observed with 10 seconds acquisition times in the artificial eye model. Weak water band between 3200 cm-1 to 3400 cm-1 could be detected in the anterior chamber of untreated eyes within 30s. Peaks at 884 cm-1 and 2930 cm-1 were also measurable in eyes injected with ethanol, although with lower peak intensities compared to the eye model. Peaks at 1002 cm-1 could be observed in eyes injected with phenylephrine.
The new device has been proven to be functional both in an artificial eye model as well as in rabbit eyes in vitro. Further improvements may be achieved by increasing laser power and optimizing the design of the device. In vivo experiment with living rabbit is on the schedule and pre-clinic applications are to be expected in near future. The device could open a major step into fast and non-invasive analysis of the internal eye fluid. Examples of clinical applications are early treatment of iritis/Uveitis and monitoring drug delivery into the eye in case of glaucoma.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only