Objective To describe the frequency doubling technology (FDT) methodology to measure visual field loss in patients with primary open-angle glaucoma.
Methods Participants with primary open-angle glaucoma were eligible performed for both Humphrey Matrix FDT perimetry and short-wavelength automated perimetry (SWAP) at the same visit (all perimeters by Carl Zeiss Meditec, Inc., Dublin,CA). FDT perimetry with the N-30 full threshold protocol and SWAP using the Humphrey Field Analyzer with Swedish interactive thresholding algorithm (SITA) SWAP were performed. Visual field defects were confirmed with two or more consecutive examinations by the same types of perimetry.
Results Sixty-nine participants had complete data were analyzed. The IOP and CCT did not differ between the 2 groups. The FDT results were abnormal in 52 cases (75.4%) and 47 cases (68.1%) had abnormal SWAP results, the sensitivity was higher for Matrix FDT perimetry with a significant difference detected between FDT and SWAP (P = 0.024), (P<0.05). The characteristic curve (AUC) of MD (mean deviation) and PSD (pattern standard deviation) followed a similar order, with Matrix FDT perimetry having higher AUC (0.86-0.92), followed by SAP (0.82-0.90). There were significant differences in sensitivities at 90% specificity between Matrix FDT perimetry and SAP (P < 0.01 for MD; P <0.05 for PSD).
Conclusions FDT perimetry is a feasible, fast, and reliable method for visual field loss screening in patients with POAG and it had a higher sensitivity for detecting glaucoma than SWAP at a comparable level of specificity. |
