Abstract
Purpose:
To determine the relationship, in glaucoma patients, between PMBT and logMAR best corrected visual acuity (BCVA), as well as the relationship between PMBT and optic nerve blood flow.
Methods:
We studied 50 eyes of 27 patients with primary open-angle glaucoma, including normal-pressure glaucoma. We used two methods to measure PMBT, both using optical coherence tomography (3D-OCT2000, TOPCON, Japan). The first method used built-in program of 3D-OCT2000 to measure retinal nerve fiber layer thickness (RNFLT) and ganglion cell complex thickness (GCCT) in a square 10-degree area centered on the macula. The second method used a new program to measure a rectangular area (1.5mm wide and 9.0mm long) centered on the mid-point of the optic nerve disc and the macula, sub-divided into three parts along its length. In the middle part of this rectangular section, we measured RNFLT and GCCT with software for the automatic analysis of NFLT developed by Yamagata University. Additionally, we measured optic nerve blood flow with Laser Speckle Flowgraphy (LSFG-NAVI, Softcare, Japan). We divided the optic nerve into superior (S), temporal (T), inferior (I), and nasal (N) quadrants and measured MA (mean MBR in all areas), MT (mean MBR in the tissue area), and MV (mean MBR in the vessel area) in each quadrant. The Spearman coefficient of correlation was calculated to determine the relationship among RNFLT, GCCT, logMAR BCVA, and optic nerve blood flow.
Results:
There was a significant correlation between RNFLT (r=-0.48) and GCCT (r=-0.56) in the central 10 degrees of the macula and logMAR BCVA. Similarly, there was a significant correlation between RNFLT (r=-0.56) and GCCT (r=-0.50) in the middle part of the new rectangular section we measured and logMAR BCVA. Moreover, there was a significant correlation between RNFLT (r=0.39) and GCCT (r=0.39) in the central 10 degrees of the macula and temporal MT. Similarly, there was a significant correlation between RNFLT (r=0.37) and GCCT (r=0.52) in the middle part of the rectangular section and temporal MT. The highest coefficient of correlation was between GCCT and temporal MT (r=0.52).
Conclusions:
There is a significant correlation among RNFLT, GCCT, and logMAR BCVA, and also among RNFLT, GCCT, and temporal MT in glaucoma patients with low PMBT. Our findings may indicate that temporal MT relates closely to low PMBT.
Keywords: 629 optic nerve