Abstract:

Objective To investigate the reproducibility of macular ganglion cell complex (mGCC) and retinal nerve fiber layer (RNFL) thickness measurements using Fourier-domain optical coherence tomography (OCT) in patients with normal tension glaucoma (NTG) and primary open angle glaucoma (POAG). Methods Normal people (normal control group, n=15), patients with NTG (NTG group, n=15) and those with POAG (POAG group, n=15) were selected, and Fourierdomain OCT was employed to measure RNFL thickness, mGCC thickness and its general loss of volume (GLV) and focal loss of volume (FLV) in each group. After 5 times of measurements by operator A at 4-h intervals, the same job was done by operator B on the following day. Inner-operator and inter-operator intraclass correlation coefficient (ICC) were adopted to evaluate the reproducibility of measurements, and area under the receiver operator characteristic curve (AROC) was used to analyse the diagnosis performance. Results ICC were >0.75 for mGCC and RNFL thickness measurements. All the measured parameters in NTG group and POAG group were significantly different from those in normal control group (P<0.05). There was no significant difference in RNFL thickness and FLV% between NTG group and POAG group (P>0.05), while there were significant differences in mGCC thickness and GLV% between these two groups (P<0.01, P<0.001). There was no significant difference in AROC between RNFL parameters and mGCC parameters (P>0.05). Conclusion The reproducibility of mGCC and RNFL thickness measurements using Fourier-domain OCT in patients with NTG and POAG is favorable. RNFL works well in diagnosis, and mGCC may serve as a good supplement.

Key words: optical coherence tomography, primary open angle glaucoma, normal tension glaucoma, macular ganglion cell complex, retinal nerve fiber layer, reproducibility