Comparative Evaluation Of Optical Coherence Tomography And GDxVCC In The Diagnosis Of Primary Open Angle Glaucoma

Objective: To evaluate the structural damage in the peripapillary retinal nerve fiber layer (RNFL) using optical coherence tomography (OCT) and scanning laser polarimetry (GDxVCC) in primary open angle glaucoma, ocular hypertension, physiologic large cups and normal eyes. And to compare the sensitivity and specificity of OCT and GDxVCC parameters for discriminating between glaucomatous and stable healthy eyes.Methods: Stratus OCT imaging of the peripapillary retina , GDxVCC imaging of the peripapillary RNFL and automated achromatic primetry were used to detect RNFL, visual field in 31cases (57 eyes) primary open angle glaucoma, 28 cases (56 eyes) ocular hypertension, 32 cases (64 eyes) physiologic large cups and 14 cases (28 eyes) normal human. The data were analyzed using SPSS13.0 for windows.Results: One hundred and five patients (205 eyes, 57 glaucomatous, 56 OHT, 64 physiologic large cups, 28 normal) were enrolled (mean age 45.17±14.39 years, range 18-76).1. The age, sexuality, diopter were not significantly different in open angle glaucomatous, ocular hypertensive, physiologic large cups and normal eyes (P>0.05).2. The superior, inferior and mean RNFL thickness were significantly less in open angle glaucomatous eyes than that in ocular hypertensive, physiologic large cups and normal eyes, whose OCT-derived RNFL thickness were not significantly different.3. The following parameters were found to be significantly correlated , TSNIT average/average thickness (γ=0.817, P<0.01) in open angle glaucomatous eyes.4. The RNFL thickness is not be significantly or mild correlated with MD, PSD of visual fields in ocular hypertensive, physiologic large cups and normal eyes. But in open angle glaucomatous eyes, the RNFL thickness is significantly correlated with MD, PSD of visual fields.5. The area under the receiver-operating characteristic curve (AUCROC) value of RNFL thickness parameters by OCT and GDxVCC , Savg, Iavg, Avg.Thick, SA, IA, TSNIT, NFI are 0.831, 0.792, 0.830, 0.798, 0.775, 0.763 and 0.790 respectively. The sensitivity of parameters by OCT and GDxVCC, Savg, Iavg, Avg.Thick, SA, IA, TSNIT, NFI are 75.44%, 68.42%, 71.93%, 66.67%, 64.91%, 59.65%, 68.97% respectively. The specificity of parameters by OCT and GDxVCC, Savg, Iavg, Avg.Thick, SA, IA, TSNIT, NFI are 96.43%, 100%, 100%, 96.43%, 96.43%, 100%, 100%.Conclusion: 1. Peripapillary RNFL thickness decreases in POAG.2. OCT and GDxVCC are significantly correlated in imaging RNFL thickness of POAG.3. The decrease RNFL thickness is correlated with the glaucomatous defect of visual fields.4. OCT and GDxVCC have good diagnostic power of glaucoma. And OCT has better diagnostic accuracy than GDxVCC in glaucoma.