Abstract
Purpose: :
To examine the relationship between the structural parameters (retinal nerve fiber layer (RNFL) thickness, macular ganglion cell complex (GCC) thickness, global loss volume (GLV), focal loss volume (FLV)) and GCC abnormal area that appears red and yellow on a significance map in optical coherence tomography (OCT).
Methods: :
The subjects all underwent standard automated perimetry testing and OCT imaging with RNFL 3.45 and the GCC mode. The GCC parameters were measured by spectral-domain OCT (RTVue-100; Optovue Inc, Frement, CA). The GCC abnormal area was measured by the image J software package (National Institutes of Health, Bethesda, MD) using a significance map. Standard visual field testing was performed using the Humphrey Field analyzer with the Swedish Interactive Thresholding Algorithm standard 24-2 test program. An analysis of variance and the Tukey multiple comparison test were used to compare the findings in the different glaucoma severity groups. The relationship among the structural parameters (GCC thickness, GLV, FLV, GCC abnormal area, RNFL thickness) was identified based on a regression analysis and the Akaike information criterion.
Results: :
One hundred five glaucoma and 35 healthy subjects were included in this study. The average GCC and RNFL were thickest in the normal group, and the thickness decreased as the severity of glaucoma increased (p<0.001). The FLV, GLV and GCC abnormal area were lowest in the normal group and increased as the severity of the glaucoma increased (p<0.001). Third-order polynomial models clearly showed the relationships between GCC abnormal area and average GCC (p<0.001), GLV (p<0.001) and RNFL thickness (p=0.0175). However, second-order polynomial models described a better relationship between GCC abnormal area and FLV (p<0.001) than Third-order polynomial.
Conclusions: :
The GCC abnormal area had curvilinear relationship with other GCC parameters. At early stage of glaucoma, the change of GCC parameters was larger than the change of GCC abnormal area.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)