Evidence that a gender difference in intraocular pressure is present from childhood

Routine assessment of intraocular pressure (IOP) is usually confined to the clinical population aged over 40 years, i.e., to those individuals considered to be most at-risk of developing glaucoma. Published IOP data collected from assumed non-glaucomatous adult subjects have shown a gender difference in this parameter, with human females recording a consistently higher value than age-matched males. A recent study has also demonstrated that a diurnal variation in IOP can be recorded in adults across normal consulting hours. IOP material is presented here, as collected in the early afternoon (14.00-14.59 hours) from n = 140 school children aged > or = 9 < 12 years. It is complemented by previously published data, also recorded between 14.00-14.59, from n = 100 middle-aged adults aged 40-59 years, and n = 102 mature adults aged over 60 years. Analysis of these three data sets indicates that a non-statistically significant gender difference in mean IOP (female > male) is present from childhood; it also suggests that, for either gender, the absolute mean level of IOP remains little altered from childhood into and throughout adulthood. However the physiological basis for these observations remains obscure.