Abstract
ABSTRACTAimTo 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 methodsA 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.ResultsOf 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).ConclusionMost 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 significanceDifferent 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 articleScoralick 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.
Highlights
intraocular pressure (IOP) mean and peak had the strongest correlation (r= 0.94; 95% CI = 0.92–0.97; p< 0.001)
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
Glaucoma is the leading cause of blindness in the world, but when detected and treated before its later stages, blindness is usually preventable.[1]Until now, intraocular pressure (IOP) remains the only modifiable risk factor for glaucoma development and progression.[2]Even though being a key parameter to evaluation glaucoma diagnosis and progression, IOP varies significantly, due to either factors associated with the measurement itself,[3]to individual patient/ocular factors.[5]
Summary
Glaucoma is the leading cause of blindness in the world, but when detected and treated before its later stages, blindness is usually preventable.[1]Until now, intraocular pressure (IOP) remains the only modifiable risk factor for glaucoma development and progression.[2]Even though being a key parameter to evaluation glaucoma diagnosis and progression, IOP varies significantly, due to either factors associated with the measurement itself (such as the type of tonometer, examiner, fluorescein, and circadian cycle),[3]to individual patient/ocular factors (such as central corneal thickness,[4]corneal hysteresis,[4] dehydration,[5]glucose levels,[6] and fasting).[5] In this context, many studies have investigated IOP variation patterns and their relationship with glaucoma management.[7,8] One of the main focuses of such studies was which IOP variation parameter would be the best predictor of glaucoma development or progression: mean, peak, or fluctuation.
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