Abstract
Purpose:
Investigate relationship between structural damage analyzed by OCT RTVue100 (Optovue, Inc.) and CirrusHD (Carl Zeiss Meditec, Dublin, CA, USA) with functional parameters of standard automated perimetry (SAP).
Methods:
143 eyes of 78 patients (96 early glaucoma, 47 moderate to severe glaucoma) and 43 control eyes were included. They had, the same day, a clinical exam with RTVue100 OCT (7*7 macular grid), CirrusHD OCT (200*200 macular grid), 24°2 and 10°2 SAP (Humphrey SITA-standard). CirrusHD segmentation includes ganglion cell layer and inner plexiform (GCIPL). RTVue associates retinal nerve fiber layer thereby defining macular ganglion cell complex (GCC). Structural damage parameters analyzed were GCC average thickness, Global and Focal Loss Volume (GLV and FLV) with RTVue, average and minimum GCIPL thickness with CirrusHD. Functional parameters collected were MD, PSD and VFI for 24°2 SAP and MD and PSD for 10°2 SAP. A Student t-test was performed to compare parameters between groups and a logistic regression analyse calculated Pearson coefficient (r) to study correlation might exist between structural and functional parameters.
Results:
Glaucoma group had a significant functional impairment in 24°2 and 10°2 SAP compared to control (MD=-5.6dB±1.1 and PSD=5.9dB±0.7 in 24°2 SAP, p<0,01 and MD=-8.3±1.6dB and PSD=7.2dB±1 in 10°2, p<0,01). Logistic regression analysis found a linear correlation between structural and functional parameters. Glaucoma group correlation coefficients were higher than control group. OCT RTVue parameters appeared to have higher correlation coefficients with functional indices than those of CirrusHD OCT (r from 0.50 to 0.72 for RTVue and 0.44 to 0.56 for CirrusHD) in 24°2 and 10°2 SAP. The highest Pearson coefficient with OCT RTVue was between focal damage indices (FLV) and PSD in 24°2 SAP (r=0.72). With CirrusHD, it was correlation between minimum GCIPL and PSD in 24°2 SAP (r=0.56). Further analysis of macular nerve fibers layer (mNFL) allowed a higher coefficient, r=0.65 between mNFL+ average GCIPL and MD of 24°2 SAP. Correlation coefficients were not different with 24°2 SAP and 10°2 SAP.
Conclusions:
This study objectives a structure function relationship between focal structural (FLV and GCIPL-Min) and functional (PSD) parameter damage with these 2 SD-OCT. If a difference between these OCT may exist, it has to be confirmed by other studies.
Keywords: 642 perimetry •
531 ganglion cells