Abstract
Abstract: :
Purpose: Difference in frequency-doubling technology (FDT) performance between open-angle glaucoma eyes with elevated pressure (primary open-angle glaucoma: POAG) and those with normal pressure (normal-tension glaucoma: NTG) and its relation to the optic nerve head topography were evaluated. Methods: Twenty-six eyes of 26 POAG patients and 37 eyes of 37 NTG patients who underwent Humphrey perimetry (central 30-2 full threshold program), FDT perimetry (N-30 threshold program) and scanning laser tomography by a Heidelberg Retina Tomograph within 3 months were enrolled. In FDT testing, patients were first tested with C-20 screening program, then with N-30 threshold program in each regularly visit. Data of the second results obtained with N-30 program were used. The mean deviation of the global indices of the Humphrey perimetry and that of the FDT perimetry were obtained. In HRT parameters, we used the cup-to-disc area ratio, rim area, mean cup depth, and cup shape measure for analyses. There was no significant difference in the disc area between POAG (2.40mm2) and NTG patients (2.34 mm2). Results: Age, refraction (spherical equivalent), and the mean deviation of the Humphrey perimetry showed no significant of inter-group difference (53.9 ± 9.4 vs 58.7 ± 9.6 years, -3.21 ± 3.05 vs –2.49 ± 3.01 dioptors, and –3.87 ± 3.33 vs –4.04 ± 3.29 dB, respectively), while the highest intraocular pressure recorded was 23.8 ± 2.5 mmHg in the POAG and 17.7 ± 1.9 mmHg in the NTG patients, (p<0.001; Mann-Whitney U-test). The mean deviation of the FDT in POAG (-5.32 + 2.72 dB) was statistically, significantly worse than that in NTG (-3.57 + 2.49 dB) (p=0.0138; Mann-Whitney U-test). While, in the HRT parameters, the rim area in NTG (1.11 + 0.28 mm2) was statistically, significantly smaller than that in POAG (1.26 + 0.32 mm2). Conclusions: The mean deviation of the FDT in eyes with POAG was significantly lower than those in NTG, although the rim area of the optic nerve head in NTG was significantly thinner than in POAG. The present results suggest FDT visual field is likely to be affected more severely in OAG with high pressure.
Keywords: visual fields • optic disc • imaging/image analysis: clinical