The technique of fluorescence angiography by arterial injection in the anaesthetized cat is described. The appearances of the angiogram as it affects the choroid, retina and optic disc, and the influence of the tapetum are recorded, and illustrated. Attempts to measure the circulation time proved disappointing, the 95% confidence limits being ±47% of the mean value, 1·06 sec. The features of the angiogram are discussed with particular reference to multiple-dye entry and injection artefacts, the difficulties of measuring circulation time in the cat, the duration of peripapillary choroidal fluorescence, and the significance of tapetal reflectance. Using rapid small-volume injections, repeated angiograms of high quality with good retinal capillary bed detail could be obtained from the healthy eye despite intense choroidal fluorescence over the tapetum which cleared before capillary detail faded.
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