OPTIMIZATION OF EARLY DIAGNOSTIC STRATEGIES FOR PRIMARY OPEN-ANGLE GLAUCOMA USING A PORTABLE ICARE TONOMETER: A COMPARATIVE STUDY

Abstract

Background:To evaluate the diagnostic utility of a portable rebound tonometer (iCare) for early detection of primary open-angle glaucoma (POAG) by comparing its intraocular pressure (IOP) measurements with those obtained using the Maklakov applanation tonometer during short-term diurnal monitoring, and to assess how central corneal thickness (CCT) influences IOP values recorded by both methods.

Methods:A prospective clinical study involving 60 patients (100 eyes) with early-stage POAG was conducted. All eyes underwent three-day diurnal IOP monitoring using both the Maklakov tonometer and the iCare rebound tonometer, with measurements taken twice daily (morning and evening). CCT was measured by ultrasound pachymetry and categorized into five groups to assess its effect on IOP readings. Comparative analysis examined the agreement between devices and the consistency of IOP fluctuations across POAG stages I and II.

Results:Across all three monitoring days, iCare-derived IOP values closely matched the Maklakov measurements in both POAG stages. In Stage I eyes, day-to-day reductions in IOP reached statistical significance (p≤0.05), while values in Stage II eyes remained stable (p>0.05). Device-level discrepancies were small (<1 mmHg on average). CCT analysis revealed that Maklakov readings were minimally influenced by corneal thickness, whereas iCare tended to underestimate IOP in ultra-thin corneas and overestimate it in thicker corneas. Nevertheless, these differences were not statistically significant.

Conclusion:Portable iCare rebound tonometry shows good concordance with Maklakov applanation tonometry and is useful for short-term IOP measurement protocols during early POAG.Recently introduced into the medical field, devices such as the iCare rebound tonometer might improve early diagnostic approaches for glaucoma because of the convenience and dynamic measurement characteristics of these devices, which are not readily achieved with standard applanation tonometry.