palpebral fissure n.
The longitudinal opening between the upper and lower eyelids.
The palpebral fissure was normal in size and there was little, if any, diminution in strength of the right radial pulse.
The palpebral fissure is smaller than its fellow, and the eyeball sinks into the orbit.
In such cases the palpebral fissure should be enlarged by dividing the outer canthus.