Real-time confocal imaging is subject to a number of constraints connected with the emission capabilities of (especially) fluorescent specimen and the particular confocal imaging technique employed. We will see that there are from the confocal image collection techniques no basic impediments towards real-time 3D imaging. The limitations sooner lie in the specimen fluorescence emission capabilities--both with respect to emission rate and total emission and of course biological tolerance limits to the exciting radiation. The various factors are examined and it is found that parallel confocal illumination and detection approaches especially via techniques of direct field (also known as direct view) confocal imaging. These combined with detection on CCD detectors offer probably the optimal and most convenient way to realize real-time imaging.