COMPARISON OF INTRAOCULAR PRESSURE MEASURED WITH GOLDMANN APPLANATION TONOMETER AND NON-CONTACT AIR-PUFF TONOMETER

Abstract

Background: Intraocular pressure measurement (IOP) is of pivotal importance for the diagnosis and management of glaucoma. The objective of this study was to compare intraocular pressure measurement with Goldmann Applanation tonometer (GAT) and non-contact Air-Puff tonometer (APT).
Material & Methods: This comparative cross-sectional study was conducted at outpatient Department of Ophthalmology, District Headquarters Teaching Hospital, Bannu, Pakistan, from October 2015 to February 2016. The IOP was measured first with APT (Canon Full Auto Tonometer TX-F, Japan) followed by its measurement with GAT (HAAG-STRIET AT 900, Koeniz Switzerland)
Results: This study included 200 eyes of 100 patients. Among 100 patients, 57(57%) were males and 43(43%)
were females. Age range was from 16 to 78 years with a mean of 42.5 years. The IOP measured with APT ranged from 10 mmHg to 47mmHg with a mean of 18.17+8.25 mmHg, while IOP recorded with GAT ranged from 10 mmHg to 41mmHg with a mean of 15.59+7.75 mmHg. There was a significant difference in the mean IOP measured with APT and GAT, with APT recording a mean IOP of 2.58 mmHg higher than GAT (p=0.003).
Conclusion: Both APT and GAT are commonly used for IOP measurement. There is a reasonably good agreement between the two tonometers at IOP within the normal range. However GAT is more accurate and reliable. APT overestimates IOP, particularly in cases above the upper limit of normal IOP. The results of APT should be confirmed with GAT, particularly when the IOP exceeds the normal range for the diagnosis and treatment of glaucoma.