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

PURPOSE: To compare provocative test-based and long-term intraocular pressure variation parameters in patients with stable open-angle glaucoma. METHODS: A prospective observational study was carried out in which stable open-angle glaucoma patients (⩾3 years of follow-up without any changes on current medical regimen) were consecutively enrolled. All patients were submitted to a water-drinking test. Long-term intraocular pressure parameters were obtained from isolated intraocular pressure measurements from each visit (⩾5 visits). We investigated the correlation and agreement between the following water-drinking test and long-term intraocular pressure parameters: mean, peak, and fluctuation. In addition, the percentage of eyes with significant intraocular pressure peaks during the water-drinking test (defined as a difference ⩾25% between water-drinking test intraocular pressure peak and mean long-term intraocular pressure) was assessed. RESULTS: Sixty-three eyes from 63 open-angle glaucoma patients (mean age, 60.7 ± 11.8 years) were included. Mean and water-drinking test intraocular pressure peak correlated significantly with mean (r = 0.67) and maximum long-term intraocular pressure (r = 0.52), respectively (p < 0.01). The correlation between water-drinking test intraocular pressure fluctuation and long-term intraocular pressure fluctuation was not significant (p = 0.45). Limits of agreement from Bland-Altman plots exceeded the maximum allowed difference between methods (3 mm Hg) for all the intraocular pressure parameters analyzed, suggesting poor agreement between water-drinking test-derived and long-term intraocular pressure values. Overall, significant water-drinking test intraocular pressure peaks were observed in 39.7% of these eyes with stable open-angle glaucoma. CONCLUSION: Although some water-drinking test-based and long-term intraocular pressure parameters correlate significantly, water-drinking test results may not reflect the long-term intraocular pressure profile of stable open-angle glaucoma patients, as their agreement is poor. Many of these patients may experience significant water-drinking test intraocular pressure peaks, despite long-standing stable disease and unchanged medical regimen.

Retinal Sensitivity Thresholds Obtained Through Easyfield and Humphrey Perimeters in Eyes with Glaucoma: A Cross-Sectional Comparative Study.

OBJECTIVE: To compare global retinal sensitivity thresholds obtained through the Easyfield perimeter (EF) and Humphrey visual field analyzer (HFA). DESIGN: Observational cross-sectional study. PARTICIPANTS: Glaucomatous patients and glaucoma suspects enrolled between October 2018 and April 2019. MATERIALS AND METHODS: All participants underwent EF (SPARK Precision) and HFA perimetry (SITA-Standard). After inclusion, demographic and ocular data were collected, including measurements of retinal nerve fiber layer (RNFL) thickness obtained from spectral-domain optical coherence tomography (SD-OCT). Global indices (mean deviation, MD; pattern standard deviation, PSD) values were compared between perimeters, and their correlation and agreement were evaluated. We used regression analysis to investigate structure-functional correlations between SD-OCT measurements and MD index of each perimeter. RESULTS: We investigated 111 eyes from 69 patients. Mean MD (mean difference=1.49dB) and PSD values (mean difference=0.42dB) from the HFA were significantly larger than those from the EF perimeter (p<0.001). There were significant linear correlations between EF-MD and HFA-MD (r=0.56), and EF-PSD and HFA-PSD (r=0.38; p<0.001). We found significant non-linear associations between average RNFL thickness and MD values derived from both EF (R2=0.41) and HFA (R2=0.17) perimeters (p≤0.012). A difference <2dB between EF-MD and HFA-MD was found in 53% of the eyes, while 71% of them had a difference <1dB between EF-PSD and HFA-PSD. CONCLUSION: While we found a moderate correlation and a small mean sensitivity difference between test results, EF's correlation with structural measurements was at least comparable to that of the HFA. Our findings suggest that although these tests should not be used interchangeably, EF SPARK Precision could be used as an alternative for functional assessment in eyes with mild glaucoma.

Peak, Fluctuation, or Mean? A Correlation Analysis of Long-term Intraocular Pressure Variation Parameters in Patients with Stable Glaucoma.

AIM: To perform a correlation analysis between long-term intraocular pressure (IOP) variation parameters (mean, peak, and fluctuation) in patients with stable open-angle glaucoma (OAG). MATERIALS AND METHODS: A cross-sectional observational study was carried out, in which patients with stable OAG were consecutively enrolled. All patients had to have glaucomatous optic neuropathy and characteristic visual field (VF) defects. Key inclusion criteria were ≥5 VF tests, ≥3 disc photographs, and ≥3 years of follow-up without any changes in current medical regimen. Stable OAG was defined as nonprogressive VF results and absence of anatomical changes for at least 3 years. Long-term IOP variation parameters were obtained from isolated IOP measurements from each visit (minimum of five IOP measurements). The main outcome measure was the correlation between these IOP variation parameters. RESULTS: Of the 63 patients studied, 37 (59%) were women, and the mean age was 61 ± 12 years. Among all the analyses, IOP mean and peak had the strongest correlation (r = 0.94; 95% CI = 0.92-0.97; p < 0.001). There were also significant correlations between IOP peak and IOP fluctuation (r = 0.84; 95% CI = 0.75-0.90; p < 0.001), and mean IOP and IOP fluctuation (r = 0.62; 95% CI = 0.43-0.75; p < 0.001). CONCLUSION: Most long-term IOP variation parameters evaluated seem to be highly correlated. Notably, the correlation between mean IOP and IOP peak was the strongest one. We believe this fact should be taken into consideration as their inclusion as individual variables in a multiple regression model could lead to misinterpretation of the data. CLINICAL SIGNIFICANCE: Different well-designed studies are conflicting regarding which long-term IOP variation parameter is more clinically relevant. Our findings suggest that collinearity issues could explain in part the discrepant results among these studies evaluating the relationship between long-term IOP variation parameters and glaucoma prognosis. HOW TO CITE THIS ARTICLE: Scoralick ALB, Gracitelli CPB, et al. Peak, Fluctuation, or Mean? A Correlation Analysis of Long-term Intraocular Pressure Variation Parameters in Patients with Stable Glaucoma. J Curr Glaucoma Pract 2019;13(1):28-31.