Both macular ganglion cell layer (GCL) and ganglion cell inner plexiform layer (GCIPL) thicknesses can be used by physicians to identify early glaucoma, according to research published in Ophthalmology Glaucoma. 

Researchers conducted a 2-armed, cross-sectional analysis comparing GCL and GCIPL thickness as methods of glaucoma detection. Cohort 1 consisted of 58 eyes with glaucoma and 125 control eyes. Cohort 2 included 28 control eyes, 45 glaucoma suspect eyes, and 72 eyes with glaucoma. The investigators used thickness measurements in cohort 1 and deviation maps in cohort 2 to compare the efficacy of both methods for detecting early glaucoma structure damage.    

The researchers noted mean deviations of -3.7±1.6 and -2.7±1.8 dB in cohorts 1 and 2, respectively. Using area under the receiver operating characteristic curves (AUC), they determined that superior and inferior sector 3 thickness provided the best discrimination with both GCL and GCIPL (inferior GCL AUC: 0.860 vs GCIPL AUC: 0.916, P =.001; superior GCL AUC: 0.916 vs GCIPL AUC: 0.900, P =.24). The global GCIPL thickness of the central 18×18˚ macular region performed better than GCL for early detection of glaucoma (AUC: 0.928 vs. 0.884; P =.004), according to the report. 

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Investigators acknowledge the better performance of GCIPL reported in the analysis, but state that both methods are effective in identifying early glaucoma. 

“The lower performance of GCL as compared to GCIPL in some of the analyses could also be explained by segmentation and alignment errors in the inner macular layer, as well as concurrent changes within the inner plexiform layer in early glaucoma,” according to the researchers. “Both GCL and GCIPL measures may be used effectively for identifying early macular structural damage with the current SD-OCT technology.”

Study limitations include the sole use of SD-OCT to identify glaucoma and the difference in size between the 2 cohorts. 

Disclosure: This research was supported by Heidelberg Engineering. Please see the original reference for a full list of disclosures. 


Mahmoudinezhad G, Mohammadzadeh V, Martinyan J, et al. Comparison of GCL and GCIPL measures for detection of early glaucoma. Ophthalmol Glaucoma. Published online June 30, 2022. doi:10.1016/j.ogla.2022.06.008