Abstract: Normal-tension glaucoma (NTG) is a chronic progressive optic neuropathy, in which the intraocular pressure (IOP) is within the normal range. More and more evidence shows that NTG accounts for a high proportion of open-angle glaucoma. In the diagnosis of NTG, 24-hour IOP measurement is particularly important, and it is the main sign to differentiate NTG from POAG. The 24-hour IOP monitoring of NTG patients usually shows peak intraocular pressure at night, and the diurnal fluctuation of IOP is often larger than normal. In addition, the average IOP, short-term and long-term IOP fluctuation amplitude and minimum IOP value of 24 h IOP are all the predictive parameters of NTG disease progression. This makes the 24-hour IOP monitoring of NTG patients and individualized treatment based on the characteristics of their 24-hour IOP fluctuation become particularly important. (Int Rev Ophthalmol, 2023, 47: 24-29)

Key words: normal-tension glaucoma, primary open-angle glaucoma, fluctuation of intraocular pressure