Clinical Comparison Of Intraocular Pressure Measurements Using Goldmann And Proview Tonometry.

Background:The Proview tonometer (Bausch & Lomb, Rochester, NY), the new pressure
phosphene tonometer, would allow glaucoma patients to monitor intraocular pressure (lOP) by themselves and at various times of the day. The diumal variation in one's lOP that is known to exist can play an important role in the management of glaucoma. Unfortunately, there has never been an efficient way to self-monitor lOP. However, the Proview tonometer, if proven an accurate means ofiOP measurement, would provide doctors insight into the patients diurnal variations and allow for the most appropriate medical management of the
disease. Methods: A total of 50 non-glaucoma patients (100 eyes) were measured over a 4-week
period. Each subject was thoroughly instructed on the use of the Proview Tonometer by an examiner. The subject was then allowed to "practice" seeing the pressure phosphene by using their finger in place of the Proview Tonometer. After each subject acknowledged to a complete understanding of the procedure, they were to perform Proview tonometry on themselves, with one reading being taken on each eye. The same examiner who gave the instructions recorded the lOP measurements. Goldmann tonometry was then performed one time on each eye of every subject. This was done by a different examiner and the results
recorded. There was no corrummication between the different examiners regarding the results of each method. Results: 15% ofthe measurements were within +/- lmrnHg, 35% ofthe measurements
were within +/-2mmHg, and 37% of the measurements differed by 5mmHg or more. The average difference between readings for all of the measurements was 4.05mmHg. For Proview tonometry, the mean lOP was 15.12mmHg with a standard deviation of3.86 and a range of 19mmHg (8-27mmHg). With Goldmann, the mean was 15.35mmHg with a standard deviation of3.18 and a range of l4mmHg (9-23mmHg). The t test for paired data showed a P value of 0. 64 with a correlation coefficient of 0.017. Conclusions: lOP measurements taken by the test subject with the Proview tonometer did not correlate with measurements taken with Goldmann tonometry. This suggests that
Proview tonometry does not prove to be an accurate alternative method for measuring lOP when the subject is taking the measurement. One of the main proposed uses of the Proview tonometer is self-administered home testing of lOP. However, this potential use may provide inaccurate information regarding lOP measurements due to the poor correlation with Goldmann. lOP measurements taken by the test subject with the Proview tonometer did not correlate with measurements taken with Goldmann tonometry. This suggests that Proview tonometry does not prove to be an accurate alternative method for measuring lOP when the subject is taking the measurement. One of the main proposed uses of the Proview tonometer is self-administered home testing of lOP. However, this potential use may provide inaccurate information regarding lOP measurements due to the poor correlation with Goldmann.