THE FINDING by Daniel,1 confirmed by Cooper and Daniel2 and Sunderland,3 of muscle spindles in the extraocular muscles of the human eye, and also in the eyes of other animals with mobile eyes, raises the question of the possible function of these end-organs. It has been shown by Irvine and Ludvigh4 that the human eye appears to have little, if any, position sense. These authors concluded:
The proprioceptive sense in the extra-ocular muscles has been tested for and found lacking by application of the usual criteria, namely: (1) histologic and anatomic evidence, (2) vibration sense, (3) myotatic reflexes and (4) position sense. For the possibility that ocular proprioceptive nerves not mediating position, operating at a low level, exist there is no physiologic evidence.
The very existence of muscle spindles in the human eye completely invalidates the first line of evidence quoted above. Criteria 2, 3, and
LUDVIGH E. POSSIBLE ROLE OF PROPRIOCEPTION IN THE EXTRAOCULAR MUSCLES. AMA Arch Ophthalmol. 1952;48(4):436-441. doi:10.1001/archopht.1952.00920010445007