Intraocular pressure (IOP) varies naturally throughout the day and on different days. That is why the ophthalmologist will often ask you for a "pressure curve", showing the pressure measurement every 3-4 hours on the same day in order to be able to assess variations in IOP for the patient. This is very important as recent studies suggest that fluctuations in intraocular pressure can be harmful to the optic nerve. The ideal treatment for glaucoma not only contemplates reducing IOP but also minimizing variations throughout the day.