Abstract
Purpose: :
Precise measurement of intraocular pressure (IOP) remains an essential aspect of the management of glaucoma. Several factors may influence tonometric readings. Some individuals may hold breathing while tonometry is being performed. The purpose of this study was to investigate if breath holding has an impact on IOP measurement in patients with glaucoma.
Methods: :
Patients with open angle glaucoma were included. Patients that had undergone surgical procedures were excluded. Patients were also excluded if they had any respiratory problem or had any medical treatment for respiratory diseases. Patients with corneal problems preventing accurate readings were also excluded. IOP was measured with a Perkins tonometer in the seated position. A first basal measurement was taken with the patient breathing normally. Patients were asked to withhold breathing for 10 seconds and a second measurement was obtained. A third measurement was taken after breathing normally for 3 minutes. The IOP was measured in primary gaze and an independent observer recorded the values. The tonometer was reset to 10 mmHg after each measurement to mask the examiner. Results were analyzed using Instat3 software.
Results: :
Mean (+ SD) age was 64.7 (11.3) years-old. There were 15 females and 7 males. There were no differences between right and left eyes. Mean (+ SD) IOP (mmHg) in the right eyes was 11.4 (2.5), 12.5 (3.2), and 10.8 (2.6), for the basal (A), breath holding (B) and after 3 minutes (C) measurements. IOP after breath holding was higher than the basal IOP (p<0.01) and the post 3 minutes measurement (p<0.001). No difference was found between A and C.
Conclusions: :
Breath holding for 10 seconds can modify IOP. Patients should be instructed to breath normally while measuring IOP. These variations should be considered in the management of glaucoma and the evaluation of different treatments.
Keywords: intraocular pressure