Abstract
Abstract: :
Purpose:To compare FDT Perimetry indices with those of standard Octopus perimeters in patients with glaucoma, glaucoma suspects and normal control group respectively; and also to evaluate the sensitivity and specificity of FDT Perimetry in detection of glaucomatous visual field loss. Methods:In a prospective study, 168 eyes(normal 30, POAG 53, PACG 49 and glaucoma suspects 36) were assessed by the FDT Perimetry (C-20 full threshold) and Octopus Perimetry (TOP) respectively. The participants underwent fundus stereo photography for optic disc and retina nerve fiber layer analysis.In the comparison of the total visual field, for Octopus perimeters, mean defect [OCT-MD], mean sensitivity [OCT-MS], and loss variance [OCT-LV] were calculated and used for correlation; For the FDT, mean deviation [FDT-MD] and pattern standard deviation [FDT-PSD] were calculated and used for correlation. For the four divided quardrants visual field comparison, each quardrants of the visual fields were scored depending on the severity of loss in every measured spot. The total scores of each quadrants were calculated for the comparison between FDT and Octopus Perimetry.The glaucomatous visual field loss was classified as early (MD no worse than -5dB), moderate (MD between -5dB and -10dB) or advanced (MD between -10dB and -20dB). The sensitivity and the specificity of FDT perimetry for detecting glaucomatous visual field loss were estimated and the method was statistically evaluated with ROC Curves. Results:When compared with either FDT-MD or FDT-PSD, significant differences were found between the normal control group and the glaucoma group. In the glaucoma group, a statistically significant correlation (Pearson's r, P<0,001) was found between FDT-MD and both OCT-MS (0.837) and OCT-MD (0.858); also significant correlation was found between FDT-PSD with Octopus-LV (0.683). In the normal and glaucoma suspect group, no significant correlation was found. When the visual field was divided into four quadrants, a similar correlation was found between the indices. The sensitivity of FDT was 100% for detecting moderate and advanced visual field loss and approximately 80% for detecting early visual field loss, the specificity was 86% .The area under under the ROC curve was 0.851. Conclusion:FDT Perimetry has similar clinical efficacy as the Octopus Perimetry in detecting glaucoma visual field loss; FDT has good sensitivity and specificity for detection of early, moderate and advanced glaucoma visual field loss, and it may be a potential tool for glaucoma screening.
Keywords: 624 visual fields • 511 perimetry