BACKGROUND: The purpose of the present study was to determine the effect of positive end-expiratory pressure on intraocular pressure under general anesthesia. METHODS: Contact tonometer HA-1 (Kowa, Japan) was used to measure the intraocular pressures of 22 subjects at zero end-expiratory pressure and positive end-expiratory pressure of 15 cmH2O under general anesthesia. The data were statistically analyzed by paired t-test. RESULTS: There is no statistically significant difference between intraocular pressure of zero end-expiratory pressure and positive end-expiratory pressure of 15 cmH2O in a population with normal basal ocular tonometry. CONCLUSIONS: Mechanical ventilation with positive end-expiratory pressure of 15 cmH2O under general anesthesia dose not present a clinically important significant risk for intraocular pressure increase in a population with normal basal ocular tonometry.