Normal intraocular pressure in children: a comparative study of the Perkins applanation tonometer and the pneumatonometer.

We measured the intraocular pressure (IOP) of 50 normal, cooperative, awake children below 5 years of age and 12 normal, volunteer adults with the Perkins hand-held applanation tonometer (Perkins) and the Digilab pneumatonographer-tonometer (Pneuma). Neither sedation, general anesthesia, nor lid specula were used. We confirmed others' findings that the normal IOP, measured in the supine position with the Perkins, is lower in infants and young children (mean = 5.89 mm Hg) than in adults (mean = 13.21 mm Hg; P < .0001). On the other hand, with the Pneuma, the supine pediatric IOP (mean = 14.76 mm Hg) was not significantly different from the adult sitting IOP (mean = 14.42 mm Hg; P = .497). Regression analysis suggests that children and adult Perkins IOP may become equal at around age 12 years.