Self-tonometry as a complement in the investigation of glaucoma patients

Purpose To evaluate the reliability of intraocular pressure measured by patients with glaucoma themselves using a new hand-held tonometer and to observe whether the intraocular pressure (IOP) variations have the same pattern on different days while glaucoma treatment is constant. Methods Eighty-seven patients diagnosed with open-angle glaucoma or ocular hypertension were recruited to the study. Intraocular pressure measured using Goldmann applanation tonometry (GAT) was compared with IOP measured using tonometry at baseline and on the second visit. Patients measured their IOP at home using the hand-held tonometers. Results The mean difference between GAT and iCare® values varies from 0 to 1 mmHg. Seventy-eight per cent of iCare® measurements were within 3 mmHg of the GAT measurements. Approximately 64% of the study eyes had higher IOP in the morning than in the afternoon/evening. Circadian patterns differed between consecutive days in 47% of the study eyes. There were IOP peaks outside office hours in up to 16% of the study eyes. Conclusion Measurements made using rebound self-tonometry are accurate and could be used to complement the investigation of patients with glaucoma. Intraocular pressure curves provide valuable data usable when adapting glaucoma treatment.