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Kenzo Koike, Megan Hohenberger, Kendall Wannamaker, Rupal H Trivedi, Jan A Kylstra, Department of Ophthalmology, Medical University of South Carolina; Noise Field Perimetry for Screening Central Scotomas in Age Related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3152.
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© ARVO (1962-2015); The Authors (2016-present)
Noise field perimetry (NFP) is a technique that utilizes small black and white spots flickering randomly at high frequency (“television static”) to detect visual abnormalities in macular disease, and was previously shown to be more effective than Amsler grid (AG) in detecting diabetic macular edema. However, the Amsler grid (AG) continues to be the primary method for self-detection of central scotomas correlating to early progression of age related macular degeneration (AMD). We performed a cross-sectional clinical study to determine if NFP is an effective screening tool for detecting progression of AMD, and how it specifically compares with AG testing.
Patients with a documented history of AMD were selected to undergo both AG and NFP testing. Patient responses from the testing were graded on a 5-point scale to determine their certainty of a central scotoma. Optical coherence tomography and clinical exam findings were reviewed to correlate with results from the AG vs. NFP testing, and used to diagnose patient eyes with dry vs. exudative AMD. A “4” or greater was considered a positive response for detection of central scotomas. Sensitivities and specificities were calculated, and chi-square test was used for analysis.
Results: AG had a sensitivity of 67.3% and specificity of 66.7% for detection of exudative AMD, while NFP had a sensitivity and specificity of 51.0% and 66.7%, respectively (n = 82 eyes; 49 dry, 33 exudative). AG sensitivity was significantly greater than NFP (p < 0.05). Both testing methods (AG and NFP) were analyzed together, and showed a combined sensitivity and specificity of 73.5% and 57.6%, respectively. Receiver operator characteristic (ROC) curves for each test are shown in the attached figures (95% confidence intervals included as gray lines):
Conclusions: NFP was shown to be effective for detecting progressive (exudative) AMD, but was not as sensitive as AG testing. Analysis of the two tests combined showed increased sensitivity for detecting exudative AMD, compared to either test alone. Thus, future investigations should consider evaluating a combined testing approach as a more effective modality for AMD screening.
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