Abstract
Purpose:
The aim of this study is to evaluate the glaucoma discriminating ability of macular layers measured by spectral domain optical coherence tomography (Cirrus HD-OCT, Carl Zeiss Meditec (CZM), Dublin, CA, USA).
Methods:
This study concerns 252 eyes of 120 glaucoma patients treated for primary open angle glaucoma (POAG) (164 early POAG, 44 moderate POAG and 44 advanced POAG) and 337 eyes of 148 normal control subjects. Every patient underwent a visual field testing (Humphrey Field Analyser, SITA-Standard 24-2, CZM), and SD-OCT imaging (Cirrus HD-OCT) in the macular (Ganglion Cell Analysis (GCA), macular cube 200x200) and optic nerve head regions (optic disc cube 200x200). OCT macular scans were segmented into macular nerve fibre layer (mNFL), ganglion cell layer with inner plexiform layer (GCIPL) and ganglion cell complex (GCC) (mNFL + GCIPL). Glaucoma discriminating ability was assessed using the area under the receiver operator characteristic curve (AUC) for all macular parameters and mean circumpapillary retinal nerve fibre layer (cpRNFL).
Results:
There is a statistically significant difference between glaucomatous eyes and control eyes for every parameters (p <0.05). Parameters with the best AUCs in the early POAG group were the minimum GCIPL (0.747 (Se = 46.4%, Sp = 89.9%)), average GCIPL (0.716 (Se = 52.4%, Sp = 84.3%)), GCC (0.710 (Se = 86.0%, Sp = 47.5%)), cpRNFL (0.704 (Se = 39.0% sp = 92.42%)), minimum mNFL (0.673 (Se = 28.0%, Sp = 92.6%)) and average mNFL (0.655 (Se = 31.0%, Sp = 95.0%)) Parameters with the best AUCs in the moderate POAG group were the minimum GCIPL (0.864 (Se = 65.9%, Sp = 92.3%)), GCC (0.858 (Se = 47.7%, Sp = 94.9%)), cpRNFL (0.853 (Se = 36.6% sp = 99.0%)), average GCIPL (0.838 (Se = 13.6%, Sp = 98.5%)), average mNFL (0.820 (Se = 79.5%, Sp = 76.0%)) and minimum mNFL (0.815 (Se = 59.1%, Sp = 95.2%)). Parameters with the best AUCs in the advanced POAG group were the minimum GCIPL (0.938 (Se = 86.4%, Sp = 93.5%)), GCC (0.928 (Se = 68.2%, Sp = 97.3%)), minimum mNFL (0.920 (Se = 63.6%, Sp = 97.6%)), average GCIPL (0.908 (Se = 50.0% sp = 98.5%)), cpRNFL (0.854 (Se = 52.4 %, Sp = 100.0%)) and average mNFL (0.854 (Se = 52.4 %, Sp = 100.0%)).
Conclusions:
The minimum macular GCIPL is a new index obtained with the GCA algorithm of Cirrus-HD OCT. It seems to have an excellent ability to detect glaucoma at every stage with a better performance than peripapillary RNFL.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
568 intraocular pressure