Ocular fluorometry has been recognized as a relevant noninvasive technique in ophthalmology diagnosis and research. Fluorometric methods are widely used namely for measuring some of the major physiological parameters of clinical significance: measurement of corneal epithelial and endothelial permeability, use of sodium fluorescein (a well known exogenous fluorophore) to estimate the aqueous flow, and, most important, to measure the permeability of blood-ocular barriers that can give an early indication of diabetic retinopathy, etc. Ocular fluorometry instrumentation relies on the performance of light detectors based on different technologies. The trend, over the past few years, seems to be the increasing use of solid state ones, namely the so-called photodiode arrays (PDA). Good quantum efficiency, wide spectral range, inherent spatial resolution, good reproducibility and low dark current make them appropriate to measure ocular fluorescence light intensity distribution along the eye optical axis. When the light levels to be measured are very low, special care must be focused on the parameters and the working conditions of these devices so that their quantitative results can be meaningful and reliable. Cooling to reduce dark current, slow data rates to allow for longer exposure times increasing sensitivity, high gain and low noise amplification can be listed as some of the operation requirements. The study of the specific nonuniformity profile of the sensor used is another important procedure.