Assessment of Intraocular Pressure Measurement Between Goldmann Applanation Tonometer and Portable Non-Contact Tonometer (TH1U).

Purpose: To investigate the consistency of intraocular pressure measurements between portable non-contact tonometer (PNCT) and Goldmann applanation tonometer (GAT). Patients and Methods: A total of 81 participants (150 eyes) who were aged ≥18 years and had no history of eye surgery within 3 months were recruited. Eyes were categorized into three IOP groups: 7-16 mmHg (n = 50, 33.3%), >16 to <23 mmHg (n = 50, 33.3%), and ≥23 mmHg (n = 50, 33.3%). All participants underwent PNCT and GAT intraocular pressure measurements in sequence, and central corneal thickness (CCT) was recorded. Pearson correlation analysis was used to evaluate the correlation between PNCT and GAT intraocular pressure results, and the intraclass correlation coefficient (ICC) and Bland-Altman method were used to evaluate the consistency. The effect of CCT on intraocular pressure measurement was further analyzed. Results: A total of 81 subjects (150 eyes) were included. The mean intraocular pressure measured by GAT and PNCT was 21.1±7.8mmHg and 21.4±7.5mmHg, respectively, with no significant difference between the two (P>0.05). The IOP values measured by the two devices were highly positively correlated (r²=0.934, P<0.001), with an ICC of 0.933, indicating good consistency. Bland-Altman analysis showed that the mean difference between GAT and PNCT was -0.2±2.8mmHg, the limits of agreement (LoA) was +5.3 to -5.8mmHg, and 93.33% of the differences fell within ±5mmHg. CCT was significantly positively correlated with the IOP values measured by both devices, but did not significantly impact the agreement between them. Conclusion: PNCT demonstrates high consistency with GAT and offers a reliable alternative for IOP monitoring. Its portability, non-contact operation, and automatic measurement function make it particularly suitable for home-based and long-term glaucoma management.