Measurements of Intraocular Pressure with Tono-Pen and Goldmann Applanation Tonometers in Subjects with Systemic Illness

Objective: The purpose of this preliminary study was to compare differences in the measurement of intraocular pressure (IOP) between TonoPen tonometry and Goldmann applanation tonometry (GAT) in healthy individuals and those with coexisting illnesses. Patients and Methods: This prospective study included 42 individuals who were further categorized into two groups. Group 1 consisted of 20 healthy individuals and group 2 contained 22 participants who had various systemic illnesses such as congestive heart failure, chronic bronchitis, uremia, liver cirrhosis and cerebral ischemia stroke. One eye of each of the 42 participants was randomly selected and the IOP was measured with the Tono-Pen and GAT. In addition, the central corneal thickness (CCT), axial length (AL) and keratometric power (K) were measured in the same eyeball of each participant. Results: There was no significant difference in the IOP values between the Tono-Pen and GAT in these two groups (p > 0.05). The average IOP values in the healthy individuals were 14.5 ± 3.5 and 13.7 ± 3.4 mmHg with the Tono-Pen and GAT, respectively. The IOP values in the subjects with coexisting systemic illnesses were 13.8 ± 2.9 and 13.1 ± 3.2 mmHg with the Tono-Pen and GAT, respectively. The IOP values were positively correlated with CCT with both the Tono-Pen (group 1, p = 0.042; group 2, p = 0.039) and GAT (group 1, p = 0.020; group 2, p = 0.015). There were no significant differences in the age of subjects, AL or K (p > 0.05) in these two groups. Conclusion: In our preliminary study, the IOP values were positively correlated with the CCT with Tono-Pen tonometry and GAT in these two groups. The IOP values were not significantly different between the Tono-Pen and GAT in the subjects with systemic illness. [Tzu Chi Med J 2007;19(4):241–244] Article info Article history: Received: April 19, 2007 Revised: May 19, 2007 Accepted: June 15, 2007