Search Results (6)

Objective: To compare intraocular pressure (IOP) measurements obtained using the Easytone Transpalpebral Tonometer (ETT) with the Icare 200 (IC200), Tonopen AVIA (TPA), and Goldmann Applanation Tonometer (GAT) in healthy individuals. Methods: Fifty-eight right eyes of 58 healthy volunteers underwent IOP measurement with all four devices. Three consecutive readings were taken per device and averaged. Two masked observers performed all measurements. Agreement was assessed using intraclass correlation coefficients (ICCs) and Bland–Altman analysis, and repeated-measures ANOVA compared mean IOP values. Results: Mean IOP values were 15.18 ± 1.88 mmHg (ETT), 14.45 ± 2.24 mmHg (TPA), 13.38 ± 2.65 mmHg (IC200), and 14.33 ± 2.03 mmHg (GAT) (p < 0.001). ETT provided significantly higher values than IC200, TPA, and GAT, while IC200 underestimated IOP compared with TPA and GAT. No difference was observed between TPA and GAT. Inter-observer agreement was excellent (ICC 0.805–1.000). Agreement analysis showed weaker ICC values for ETT–TPA (0.642) and ETT–IC200 (0.615). Bland–Altman plots confirmed the closest agreement between GAT and TPA, and the poorest agreement between ETT and IC200. Conclusions: ETT tends to overestimate and IC200 to underestimate IOP compared with GAT. TPA demonstrated the closest agreement with GAT and may be the most reliable alternative in clinical practice. ETT can be useful when applanation is not feasible, but its limited agreement should be considered. Full article

Objectives: The objective of this study was to evaluate the agreement and clinical interchangeability of intraocular pressure (IOP) measurements obtained with the mechanical Haag-Streit AT900 Goldmann applanation tonometer (mGAT) and the digital Huvitz HT5000 applanation tonometer (dGAT). Methods: This retrospective comparative study included 53 eyes of 28 patients undergoing routine ophthalmologic evaluation. Each eye underwent IOP measurement using both mGAT and dGAT in a randomized sequence. Central corneal thickness (CCT) was also recorded. Pearson’s correlation coefficient was used to determine correlation between paired IOP measurements. Bland–Altman plots were graphed for the analysis of differences for IOP between the instruments. Results: A total of 53 eyes of 28 patients (15 males) were included in the study. The mean age of the patients was 62.6 years. The mean mGAT and dGAT measurements were 16.3 ± 6.6 mmHg (range 9–50) and 16.4 ± 6.2 mmHg (range 8.8–45.9), respectively (p = 0.53). A strong, significant positive correlation was found for paired IOP measurements by the two instruments (r = 0.98; p < 0.0001). Bland–Altman analysis revealed 95% limits of agreement from −2.5 to +2.3 mmHg, with a small but statistically significant proportional bias favoring mGAT at higher IOP levels. Additionally, 91% of paired measurements were within ±2 mmHg. CCT-related differences were statistically and clinically insignificant. Conclusions: IOP measurements obtained with mGAT and dGAT were highly correlated and clinically interchangeable for the range tested. The Huvitz HT5000 may serve as a reliable alternative to the classic Goldmann tonometer in routine clinical settings. Full article

Background/Objectives: This study aimed to evaluate the clinical interchangeability of intraocular pressure (IOP) measurements between a non-contact tonometer (NCT), the TRK-3 OMNIA, and Goldmann applanation tonometry (GAT) and to assess the repeatability of TRK-3 measurements. Methods: This prospective, multicenter study included 120 subjects stratified into three IOP groups based on GAT measurements: low IOP (7–16 mmHg), intermediate IOP (>16 to <23 mmHg), and high IOP (≥23 mmHg). The study eye was randomly selected from each subject. IOP was measured using both TRK-3 OMNIA and GAT following a standardized protocol. Agreement between the two methods was evaluated using Bland–Altman analysis, 95% limits of agreement (LoA), and equivalence testing via the two one-sided test (TOST) approach with a predefined ±5 mmHg margin. Linear regression analysis was performed to characterize the relationship between TRK-3 and GAT measurements. The repeatability of TRK-3 measurements was assessed using the intraclass correlation coefficient (ICC), repeatability limit, and coefficient of variation (CV). Results: Across all subjects, the mean difference between TRK-3 OMNIA and GAT IOP measurements was −0.2 mmHg. TRK-3 OMNIA overestimated IOP in the low IOP group (mean difference: 2.1 mmHg, LoA: −1.2 to 5.4 mmHg) and underestimated in the high IOP group (mean difference: −2.4 mmHg, LoA: −5.9 to 1.1 mmHg), while agreement was highest in the intermediate IOP group (−0.2 mmHg, LoA: −2.9 to 2.5 mmHg). Despite the systematic trend, equivalence testing confirmed statistical equivalence across all groups, with 90% confidence intervals (CI) of 1.7 to 2.5 mmHg (low IOP group), −0.6 to 0.2 mmHg (intermediate IOP group), and −2.9 to −2.0 mmHg (high IOP group). Linear regression analysis found a strong correlation (r = 0.92) between TRK-3 and GAT. The TRK-3 OMNIA demonstrated good repeatability, with an ICC of 0.94, a repeatability limit of 3.12 mmHg, and a CV of 5.65%. The repeatability limits were 2.22 mmHg, 2.60 mmHg, and 4.19 mmHg in the low, intermediate, and high IOP groups, respectively. Conclusions: TRK-3 OMNIA and GAT measurements showed strong agreement, statistical equivalence, and a high correlation, supporting their clinical interchangeability. TRK-3 also demonstrated high repeatability. These findings indicate that this automated non-contact tonometer provides reliable and repeatable IOP measurements, supporting its integration into routine clinical workflows. Full article

Background/Objectives: Intraocular pressure (IOP) readings using three different methods (Goldmann applanation tonometry (GAT), Corvis ST, and iCare) were compared in patients who underwent penetrating keratoplasty (PK). Methods: An observational cross-sectional study with prospective recruitment of patients was conducted. IOP measurements were acquired using GAT, iCare, and Corvis (including both uncorrected IOP (CVS-IOP) and biomechanical IOP (bIOP)), and the agreement among methods was analyzed using Bland–Altman plots. Secondary outcomes included the influence of CCT, the number of sutures, the size of the corneal donor button, and the use of antiglaucoma topical medications on the IOP readings using the three methods. Results: Twenty-five eyes from 25 patients were included. The Bland–Altman analysis showed the narrowest limits of agreement (LoA) between GAT and bIOP (7.5 mmHg). The difference between iCare and GAT IOP showed a bias of 1.26 ± 3.8 mmHg, with increased variability in cases with more remaining sutures (p = 0.0079). A higher CCT was moderately associated with lower bIOP readings (p = 0.0067), but no significant impact of CCT on the difference in the IOP measurements between GAT and other tonometers was found. Additionally, there were no significant differences in tonometer readings based on the use of antiglaucoma medications or the corneal donor button size. Conclusions: Good agreement was found between iCare, CVS-IOP, bIOP, and GAT-IOP readings with the comparison between GAT-IOP and bIOP resulting in the narrowest 95% LoA. The difference between the GAT-IOP and iCare readings tended to be influenced by the number of sutures at the graft–host interface. Higher CCT values were associated with lower bIOP readings; however, the differences in tonometer readings compared to GAT-IOP were not found to be influenced by CCT. Full article

Intraocular pressure (IOP) is an important measurement that needs to be taken during ophthalmic examinations, especially in ocular hypertension subjects, glaucoma patients and in patients with risk factors for developing glaucoma. The gold standard technique in measuring IOP is still Goldmann applanation tonometry (GAT); however, this procedure requires local anesthetics, can be difficult in patients with scarce compliance, surgical patients and children, and is influenced by several corneal parameters. Numerous tonometers have been proposed in the past to address the problems related to GAT. The authors review the various devices currently in use for the measurement of intraocular pressure (IOP), highlighting the main advantages and limits of the various tools. The continuous monitoring of IOP, which is still under evaluation, will be an important step for a more complete and reliable management of patients affected by glaucoma. Full article

Glaucoma is the second cause of irreversible blindness in the world. Intraocular pressure (IOP) is a recognized major risk factor for the development and progression of glaucomatous damage. Goldmann applanation tonometry (GAT) is internationally accepted as the gold standard for the measurement of IOP. The purpose of this study was to search for correlations between Goldmann tonometry and corneal mechanical properties and thickness by means of in vitro tests. IOP was measured by the Goldmann applanation tonometer (GIOP), and by a pressure transducer inserted in the anterior chamber of the eye (TIOP), at increasing pressure levels by addition of saline solution in the anterior chamber of enucleated pig eyes (n = 49). Mechanical properties were also determined by inflation tests. The GAT underestimated the real measurements made by the pressure transducer, with most common differences in the range 15–28 mmHg. The difference between the two instruments, highlighted by the Bland–Altman test, was confirmed by ANOVA, normality tests, and Mann–Whitney’s tests, both on the data arranged for infusions and for the data organized by pressure ranges. Pearson correlation tests revealed a negative correlation between (TIOP-GIOP) and both corneal stiffness and corneal thickness. In conclusion, data obtained showed a discrepancy between GIOP and TIOP more evident for softer and thinner corneas, that is very important for glaucoma detection. Full article