THE IMPROVEMENT OF SOLID-STATE LIGHT SENSORS PERFORMANCE USING TEMPERATURE CONTROL IN OCULAR FLUOROMETRY APPLICATIONS

Ocular fluorometry is a non-invasive diagnostic technique that has bee n used widely in research to measure the amount of fluorescein leakage from the blood into the ocular tissues and fluids after intravenous i njection. This information has been demonstrated to be valuable in a n umber of clinically relevant situations. This paper mainly deals with demonstrating how the use of modern sensors associated with effective temperature control can configure a low-cost solution to an ocular flu orometry instrument and still upgrade the performance previously obtai ned with bench-top units only. A new ocular fluorometer is briefly des cribed and special attention is dedicated to the temperature cooling a nd control system that has been developed and to the quantification of ifs effects on the detector signal-to-noise ratio (SNR), lowest level of detection (LLOD) and error of measurement (EOM) within the context of ocular fluorometry requirements. Experimental evidence is given th at shows not only the improvements in LLOD with moderate cooling (more then 35% for a 5 degrees C decrease in temperature in the 10-20 degre es C range), but also the attenuation of the EOM by temperature stabil ization (+/-1 degrees C uncertainty in the 20 degrees C range induces a +/-1 ng ml(-1) EOM), the current LLOD being lower then 1 ng ml(-1), as we will see.