Progress in continual eye pressure monitoring

Observations of intraocular pressure (IOP) variations in response to CO2, adrenaline, speech and compression of the neck veins were documented by continual monitoring of IOP by radiotelemetry. Carbon dioxide increased IOP in the supine, but not in the erect, conscious subject. Adrenaline 2% caused a rapid short-lived painful increase in IOP, followed by a profound decrease. This was due to an increase in facility of outflow and was associated with paralysis of the sympathetic supply to the iris. Speech caused a small rise in IOP which was reversed by rest in silence. Compression of the neck veins caused a variable increase in IOP. These physiological variations in IOP may contribute to the errors of tonometry.