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J.–U. Hwang, D.–S. Kim, J. Choi, H.–S. Cho, M.S. Kook; Scanning Laser Polarimetry Using Variable Corneal Compensation in the Detection of Glaucoma With Localized Visual Field Defects . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2541.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the ability of scanning laser polarimetry parameters and a novel deviation–map algorithm to discriminate between healthy and early glaucomatous eyes with localized visual field defects confined in one hemifield. Methods: In this prospective case–controlled study, 61 glaucomatous eyes with localized visual field defects and 66 normal controls were enrolled. Humphrey field analyzer (HFA, Zeiss–Humphrey, Dublin, CA, USA) 24–2 glaucoma hemifield test and scanning laser polarimetry (GDx–VCC system, Laser Diagnostic Technologies, San Diego, California, USA) were used. We assessed sensitivity and specificity of GDx–VCC parameters, sensitivity and cutoff values for GDx–VCC deviation map algorithm scores at different specificity values (80%, 90%, and 95%) in the detection of glaucoma, and correlations between the GDx–VCC algorithms (number of superpixels at each deviation probability and severity score) and the algorithms of the pattern deviation (PD) derived from HFA testing. Results: There were significant differences between the glaucoma group and normal subjects in the mean parametric values of TSNIT average, superior average, inferior average, and TSNIT SD (P<0.05). The sensitivity of each GDx–VCC parameter was as follows: TSNIT, 47.5%; superior average, 31.1%; inferior average, 47.5%; and TSNIT SD, 24.6% (when abnormal was defined as P<0.05). The range of areas under the receiver–operating–characteristic curves using our GDx–VCC deviation–map algorithm in the detection of glaucoma was 0.79–0.89. The overall sensitivities combining each probability scale and severity score at 80%, 90%, and 95% specificity were 90.2%, 72.1%, and 59%, respectively. There was a statistically significant correlation between the GDx–VCC severity score and the visual field severity score (R2=0.408, P<0.05). Conclusions: GDx–VCC parameters may not be sufficiently sensitive to detect glaucomatous patients with localized visual field damage. Our algorithm using the GDx–VCC deviation map may enhance the detection rate and the understanding of GDx–VCC printout in terms of the locality, deviation size, and severity of localized RNFL defects in eyes with localized visual field loss.
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