Reproducibility of self-measured intraocular pressure with the phosphene tonometer in patients with ocular hypertension and early to advanced glaucoma.

Purpose: To evaluate the reproducibility of self-measured intraocular pressure with the Proview tonometer in ocular hypertensives and early to advanced glaucoma patients.

Patients And Methods: Thirty-three patients with glaucoma and three with ocular hypertension (72 eyes) were prospectively enrolled. History of cornea surgery was the only exclusion criterion. A trainer took a set of three readings first. Subsequently, the patient (after successful training) took one set of three readings and a physician took two sets of three Goldmann readings. One hour later this was repeated.

Results: 72% of patients could see the phosphene in both eyes, 8% could see it in one eye, and 19% could not see it in either eye. Patients who could not see the Phosphene had an average mean deviation of -10.9 compared with -3.4 for those who could see it (P = 0.01). Eyes that could not see the phosphene were excluded from further analysis. The average absolute difference between two Proview measurements one hour apart was 1.76 +/- 1.76 mm Hg (r = 0.71). The measurement error (difference between Goldmann and Proview readings) tended to remain constant between sets of measurements taken one hour apart (average error was 2.4 +/- 2.1 mm Hg, r = 0.85). No adverse event was recorded.

Conclusions: Repeated self-tonometry measurements showed very good reproducibility. The systematic, reproducible error between Proview and Goldmann readings may be clinically acceptable and suggests that a baseline "calibration" should be obtained for each patient before the Proview values are used clinically. Self-administered tonometry can play a role in the clinical care of ocular hypertensive and glaucoma patients with the possible exception of very advanced cases.