The unit of measurement for intraocular pressure is millimeters of mercury (mmHg). For example, this unit measures blood pressure. A healthy intraocular pressure is usually between 10 and 21 mmHg. The standard value is about 15.5 mmHg. In children and adolescents 10 to 12 mmHg are normal.
The pressure in the eye results from the amount of aqueous humor. This is a natural eye fluid that supplies the eye from within. Intraocular pressure increases as more aqueous humor is produced than can drain away. The cause of disturbances usually lies in a handicapped drain. The result of a prolonged increase in pressure is then often the green star (medical: glaucoma).
Optimal intraocular pressure varies from person to person
However, the optimal intraocular pressure is individually different. In Germany, 15-20% of people with Green Star have eye pressure values between 15 and 20 mmHg. Medical is called a normal pressure glaucoma.
The opposite case is also possible: In ocular hypertension, in German simply ocular hypertension, although the pressure values are abnormally increased, but the optic nerve is healthy (= no cataract).
Basically, in glaucoma patients: the lower the intraocular pressure, the better for the optic nerve. The desirable target pressure, however, depends on many factors and must be assessed in each case by the ophthalmologist, taking into account all findings and parameters.
Author: Dr. Hubertus Glaser