When long-term monitoring of IOP reveals that it is occasionally 1 or 2 times higher than normal and the rest of the time it is within the normal range, it is important to rule out any factors that may affect the IOP measurement, such as excessive tension, tight ties, insufficient eyelid opening, and measurement errors. The diagnosis of glaucoma is not only based on IOP, but also on the presence of glaucomatous damage to the optic nerve in the fundus and glaucomatous defects in the visual field.