Effect of Visual Field Test on Intraocular Pressure in Glaucoma Patients

<b>Objectives:</b> To evaluate changes in intraocular pressure (IOP) before versus after a visual field test in glaucoma patients. <b>Methods:</b> A total of 132 patients with glaucoma and 103 control subjects who visited Konyang University Hospital between August 2024 and May 2025 were included in the study. the right eye of each patient was selected for analysis. Visual field tests were conducted using the Humphrey Visual Field (HVF) analyzer (Zeiss Humphrey, San Leandro, CA, USA) with the SITA standard program (Central 24-2). Intraocular pressure was measured by two ophthalmologists at five time points: before the test and immediately, 10 min, 30 min, and 60 min after the test. <b>Results:</b> The average intraocular pressure decreased from 15.09 mmHg before the test to 14.29 mmHg immediately afterward; it declined further to 13.59 mmHg at 10 min in glaucoma patients. It then gradually increased to 15.01 mmHg at 60 min, returning to pre-test levels. Participants were divided into three age groups (40s, 50s, and 60s) for analysis. Across all groups, the IOP followed a similar pattern: a significant decrease for up to 10 min, followed by recovery at 60 min. Although a reduction in IOP was also observed in the control group after visual field testing, the magnitude of the decrease was smaller compared to the glaucoma patients. <b>Conclusions:</b> IOP declined immediately after the visual field test and remained lower for up to 10 min. It subsequently returned to baseline by 60 min. Therefore, when measuring the IOP after a visual field test, there is no need to adjust for temporary fluctuations if the measurement is performed 60 min after the test.