To investigate the relationship between intraocular pressure (IOP) and visual field defect progression (VFP) in normal-tension glaucoma (NTG).

We reviewed the records of patients who were enrolled according to the following inclusion criteria: at least one IOP measurement at every section, which was divided into four sections (90 minutes) by IOP measurement time and a follow-up for 2 years or more. Patients were divided into VFP (n=9) and non-visual field defect progression (NVFP, n=28) groups. The baseline IOP was defined as an average IOP measured five times with 90-minute intervals before treatment. The maximal, minimal and mean IOPs were defined as the highest, lowest and average IOPs among all checked IOPs during follow-up. IOP fluctuation was defined as the difference between the maximal and minimal IOPs. The section IOP was defined as an average IOP among all checked IOPs in each section, and section IOP fluctuation was the difference between the highest and lowest section IOPs. We reviewed and compared the IOP indices of the two groups and the risk factors, including hypertension, diabetes, migraine, familial history of glaucoma, disc hemorrhage, and number of eyedrops.

Thirty-seven eyes with an average follow-up of 50.4±18.9 months were included. The baseline and the maximal IOPs were higher than those of the NVFP group ( p =0.001 and 0.032, respectively), but the mean, minimal and IOP fluctuations were not different (all, p >0.05). All section IOPs, section IOP fluctuations and other risk factors were not different (all, p >0.05).

The baseline and the highest IOPs were a risk factor of VFP in NTG.