The author investigated a group of 240 eyes of quite healthy subjects, without hypertension and diabetes in six age decades. Each age category comprised 20 female and 20 male eyes and IOP was assessed by applanation three times a day on a Goldmann tonometer (at 7.10 a.m. and 2.30 p.m.).
Investigations of the healthy population above 21 years of age revealed that there is no direct correlation of IOP with age, although there is a slow increase of IOP from 41-70 years and after the age of 71 years there is a decline of IOP (P < 0.01). The mean value of IOP is 16 +/- 2.0 mmHg, in women the pressure is by 0.7 mmHg higher.
The mean range of IOP in both sexes is 2.8 mmHg per day. For early diagnosis of glaucoma at least a one-day curve is essential to asses not only the absolute value of IOP but also the mean value and diurnal variation.
If a subject with glaucoma and risk factors is involved, then a lower optimal individual IOP value must be considered.