Objective: To explore the applied value of ganglion cell inner plexiform layer (GCIPL) thickness asmeasured by high definition resolution optical coherence tomography (HD OCT), in the macular region of chronic angle closure glaucoma (CACG). Methods: In this descriptive study, 76 eyes of CACG patients at the Changsha Aier Hospital from December 2014 to March 2016 and 30 eyes of normal subjects were enrolled. The patients were divided into an early CACG group (37 eyes), a medium CACG group (10 eyes), and a late CACG group (29 eyes). The thickness of the macular GCIPL was made by HD OCT, and visual fields were examined in each quadrant. We compared the HD OCT and the visual field measurementsamong the different groups using one-way ANOVA, and analyzed the correlation between the average GCIPL thickness and visual field defects with Pearson correlation analysis. Results: The mean GCIPL
thicknesses in the normal group, early, medium, and late CACG groups were 85±14 μm, 84±9 μm, 72± 21 μm, 62±15 μm respectively. The difference between the 4 groups were statistically significant (F =15.89, P <0.001). The difference between the normal group and the early CACG group was not statistically significant (P =0.120), but the medium and late CACG groups were each significantly thinner than the normal group (P <0.001). The mean GCIPL was positively correlated with visual field mean differences in the glaucoma patients (r=0.636, P <0.001). Conclusions: GCIPL thickness parameters have clinical value in the diagnosis of medium and late CACG. When combined with perimetry, they can be used as an important reference index for the diagnosis, staging, and follow-up of CACG.