Related Experiment Video
Updated: Jul 21, 2026
Ultrasound Cyclo Plasty in Eyes with Glaucoma
Published on: January 26, 2018
Cross-Sectional Study of Differences between Intraocular Pressure Measurements using Goldmann, iCare, and Air-Puff
Sameh Saad Mandour1, Ahmed Elframawy2, Mohammad Moataz Murad3
1Ophthalmology Department, Faculty of Medicine, Menoufia University, Shebin El Kom, Menoufia, Egypt.
Purpose:
To investigate the agreement between the Goldmann tonometer (GAT), the air-puff tonometer, and the iCare tonometer in intraocular pressure (IOP) evaluation as well as their association with central corneal thickness (CCT) in normal participants, glaucoma patients, and patients following refractive surgery.
Methods:
This is a cross-sectional study conducted on 204 eyes from 102 patients. The study consisted of three equal groups: group I (control group, n = 34), group II (glaucoma patients on medication, n = 34), and group III (refractive surgery patients, n = 34). All patients were subjected to examination (complete ocular examination, refraction, and IOP measurement).
Results:
A total of 102 participants were included in the study with both genders distributed equally. The mean ± standard deviation age was 44.12 ± 12.8 years in the control group while it was 46.29 ± 13.24 years in the glaucoma group and 40.68 ± 15.86 years in the refractive surgery group. Overall, there was a high correlation between the three methods. The mean IOP measured by GAT was 14.03 ± 3.43. The mean IOP measured by iCare was 15.16 ± 3.46. The mean IOP measured by air-puff was 16.66 ± 3.6. The iCare showed the most significant agreement with the GAT (intraclass correlation coefficient [ICC] 0.985, P > 0.05) and the mean difference in IOP between GAT and iCare was 1.1 (95% limits of agreement, -0.62-+2.85 mmHg). The mean difference in IOP between iCare and air-puff was 1.5 and it was 2.6 between GAT and air-puff. There were no significant differences in IOP measurements between GAT and iCare tonometer or between iCare tonometer and air-puff in all groups (P > 0.05). However, there were significant differences in IOP measurements between GAT and air-puff in all groups (P < 0.001). The ICC between all studied methods was strong (ICC > 0.92 for all). Regarding CCT, the mean CCT was 517.14 ± 29.82 μm. There were significant positive correlations between increasing CCT and increasing IOP by GAT, iCare, and air-puff tonometer among the three groups (P < 0.001).
Conclusions:
In conclusion, the iCare tonometer, specifically the iCare PRO RT model, is a reliable and efficient alternative instrument for assessing IOP. The IOP values obtained with the iCare PRO RT were found to be consistent with those obtained using the air-puff and GAT.
Related Concept Videos
01:21Sites for measuring blood pressure
The Brachial Artery: Primary Site for Blood Pressure Measurement
01:30Equipments Used To Measure Blood Pressure
This invasive approach involves cannulating a peripheral artery. During each cardiac contraction, pressure generates mechanical motion within the catheter, transmitted through rigid, fluid-filled tubing to a transducer. This transducer converts mechanical motion into electrical signals displayed as waveforms on a monitor. An automatic flushing system prevents blood backflow. Due to the potential risk of unexpected arterial blood loss, this method is primarily used in intensive...
01:23Assessment of blood pressure in brachial artery(two-step method)
01:28Special considerations while measuring blood pressure
Monitoring Both Arms:
Monitoring BP in both arms during the initial assessment is advisable, as the systolic value may differ by five to ten mm Hg between arms. For subsequent BP assessments, use the arm with the higher reading.
01:17Measurement of Blood Pressure