It is well known that holding a tonometer near the eye or putting it on the cornea causes the patient to squeeze his lids because of a contraction of the orbicularis muscles. This reflex occurs regularly at the sight of an object near the eye and is generally termed a protective or fright reaction. Little attention has been paid to the part played by the oculorotary muscles during the so-called fright reaction.1,2
This study was undertaken to elucidate the reaction of the oculorotary muscles to tonometry and tonography. This seemed important in view of the pronounced influence the oculorotary muscles exercise on the intraocular pressure.3 Changes in the state of contraction of the oculorotary muscles might alter the ocular tension and introduce some inaccuracies in tonometric and tonographic measurements.
Materials and Methods
The measurements of ocular tension and of electrical activity of the oculorotary and orbicularis muscles were
KORNBLUETH W, JAMPOLSKY A, TAMLER E, MARG E. Activity of the Oculorotary Muscles During Tonometry and TonographyAn Electromyographic Study. AMA Arch Ophthalmol. 1959;62(4):555-561. doi:10.1001/archopht.1959.04220040017002