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J.E. DeLeon, C.A. Girkin, S. Arthur, K. Carroll; Frequency Doubling Technology (FDT) Perimetry and Retinal Nerve Fiber Layer Thickness in Non–Arteritic Ischemic Optic Neuropathy (NA–AION) . Invest. Ophthalmol. Vis. Sci. 2005;46(13):643.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To compare the extent of visual field loss and the correlations to retinal nerve fiber layer thickness (RNFL) in NA–AION measured with standard perimetry (SAP–SITA 24–2) and FDT (24–2). Methods: 21 eyes from 21 patients with NA–AION and 34 eyes from 34 normal participants had a comprehensive eye exam, and completed both SAP–SITA and FDT and RNFL thickness measured with Optical Coherence Tomography. The number of points outside the 95 % confidence interval (CI) was obtained from the total deviation plot from SAP–SITA and FDT for the entire field, superior and inferior hemifields, and in 6 sectors corresponding to regions of the optic nerve. The sensitivity values from perimetry tests were also matched to the respective sectors of the optic nerve. Wilcoxon test was used to compare the number of abnormal points (score mean) between perimetry tests. Non–parametric pairwise correlations (Spearman Rho) were determined between sensitivity values from the perimetry tests and RNFL for each sector. Results: Smaller values of the RNFL were observed for NA–AION compared to normal eyes for the sectors supero–nasal, nasal, infero–temporal, temporal and supero–temporal (p < 0.01). No difference was found for the infero–nasal sector (p = 0.2628). For inferior and superior hemifields, and entire field, no differences were found between mean numbers of abnormal points for FDT compared to SAP–SITA (score mean = 24.74, 23.26 and 23.36 for FDT, and 19.39, 20.79 and 20.71 for SAP–SITA respectively; p=0.1604, 0.5181, and 0.4959 for inferior, superior and entire field). The mean sensitivity values from all six sectors from FDT were significantly lower compared to SAP–SITA sensitivities (p < 0.01). Significant correlations from all six sectors were found between SAP–SITA and RNFL (Rho = 0.66, 0.55, 0.35, 0.51, 0.68 and 0.42 for supero–nasal, nasal, infero–temporal, infero–temporal, temporal and supero–temporal respectively; p < 0.01). Significant correlations were found between FDT and RNFL for all sectors (Rho = 0.57, 0.51, 0.35, 0.62 and 0.31 for supero–nasal, nasal, infero–temporal, temporal and supero–temporal respectively p < 0.05) except for infero–nasal sector (p = 0.1922). Conclusions: FDT showed more extensive defects in the entire field, inferior and superior hemifields compared to SAP suggesting greater damage measured with FDT technique. Similar correlations were found between sensitivity values from SAP–SITA and FDT perimetry test with RNFL.
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