Lack of association between provocative test-based intraocular pressure parameters and functional loss in treated glaucoma patients

Abstract

To correlate provocative test-based intraocular pressure (IOP) variation parameters (fluctuation and peak) with functional status, and to compare these IOP parameters between treated eyes with asymmetric primary open-angle glaucoma (POAG). Methods: A prospective observational study including consecutively treated patients with primary open-angle glaucoma was performed. Subjects with ocular diseases other than glaucoma or previous incisional glaucoma surgery were excluded. The primary inclusion criteria were ≥3 visual field tests and ≥2 years of follow-up, without any changes on current medical regimen. Long-term intraocular pressure parameters were acquired via isolated intraocular pressure measurements from the patients' last 5 office visits. To evaluate provocative test-based intraocular pressure parameters, all patients were submitted to a water drinking test. Initially, the partial correlation coefficients between each intraocular pressure variation parameter and visual field mean deviation were calculated, adjusting for the baseline intraocular pressure and number of antiglaucoma medications. In addition, each intraocular pressure parameter was compared between eyes with better visual field mean deviation and fellow eyes with worse visual field mean deviation in patients with asymmetric visual field loss (defined as an inter-eye visual field mean deviation difference of at least 3 dB). Results: A total of 87 eyes (87 patients; mean age, 61.9 ± 12.5 years; 59.8% women) with primary open-angle glaucoma were included. The patients underwent a median of 5 visual field tests, with a mean follow-up of 4.3 ± 1.4 years. Neither long-term nor water-drinking test intraocular pressure variation parameters were significantly associated with visual field mean deviation values (p≥0.117). In the subgroup with asymmetric visual field loss (64 eyes of 32 patients; mean age, 65.0 ± 11.4 years), neither long-term water-drinking test intraocular pressure variation parameters differed significantly between eyes with better and worse visual field mean deviation (p≥0.400). Conclusion: Our results indicate that neither long-term intraocular pressure variation parameters nor stress test-derived intraocular pressure metrics, as assessed by the water-drinking test, appear to correlate with the visual field status or differ significantly between eyes with asymmetric visual field damage, suggesting that other factors may explain such functional asymmetry, and that the water-drinking test does not add significant information to these cases.

Comparison between provocative test-based and long-term intraocular pressure parameters in patients with stable open-angle glaucoma

“…27 Therefore, we questioned the real clinical relevance of a difference of less than 1 mm Hg in the WDT IOP peak in these eyes with such asymmetric VF defect. In fact, a recent study from Scoralick et al, 39 in which several WDT-based IOP parameters were compared between eyes with asymmetric VF damage, found no significant differences between eyes with better and worse VFMD. Scoralick et al 39 suggested that other factors could better explain such asymmetric VF loss rather than stress test–derived IOP metrics.…”

“…All VFs were performed using 24-2 Swedish Interactive Threshold Algorithm (Humphrey Field Analyzer II, Carl Zeiss Meditec, Dublin, USA), and they were excluded if presenting more than 33% fixation losses or false-negative errors, or more than 15% false-positive errors. Similar to the criteria we adopted in our previous studies, 37,39 VFs were reviewed and excluded in the presence of artifacts such as lid or rim artifacts, fatigue effects, inattention or inappropriate fixation. VFs were also reviewed for the presence of abnormalities that could indicate diseases other than glaucoma, such as homonymous hemianopia.…”

“…Considering these circumstances, several studies have investigated the relationship between different short- and long-term IOP variation parameters, such as peak and fluctuation, and glaucoma progression. 30–39 However, there are scant data comparing provocative test (such as the WDT) results and long-term IOP profile in patients with stable open-angle glaucoma (OAG). 29 Therefore, it is still uncertain whether eyes with stable disease would have similar short-term (WDT-based) and long-term IOP values, and if WDT outcomes would provide an adequate estimation of patients’ long-term IOP profile.…”

Continuous 24-hour measurement of intraocular pressure in millimeters of mercury (mmHg) using a novel contact lens sensor: Comparison with pneumatonometry

“…However, no alternative could be found to assess the capability of the lens to measure IOP values as no tonometry measurement can be performed when the lens is on the eye, and IOP values notoriously differ between fellow eyes. This has also led the investigators to consider the mere amplitudes of IOP variations to assess the ability of the lens to detect IOP variations in the contralateral eye, as these were shown to be relatively similar between both eyes, even in asymmetric glaucoma [31].…”