The Application Of Estimated Macular And Retinal Ganglion Cells Count In The Diagnosis Of Glaucoma Research

Objectives:To integrate the measurement of structural and functional tests to provide estimated macular and total retinal ganglion cell(RGC).To evaluate the ability of estimated macular and total RGC counts to discriminate between healthy and glaucomatous eyes,and to discriminate various stages of the disease.Methods:This was a cross-sectional study,including 89 eyes of 70 patients with POAG and 30 eyes of healthy as control subjects.All eyes underwent 24-2 and 10-2 standard automated perimetry(SAP),RNFL and macular GCC imaging using high-definition optical coherence tomography(OCT).The total number of RGCs(eRGC)was estimated using a previously described model that uses SAP(24-2)and OCT circumpapillary retinal nerve fiber layer(cpRNFL)measurements.The number of macular RGCs(mRGC2)was estimated with the help of a model already published by Medeiros et al.combining light sensitivities SAP(24-2)test points within the central 10°and the temporal cpRNFL.Because SAP(10-2)test evaluates a much larger number of points in the macular area compared with the 24-2test and may improve the characterization of macular damage,SAP 10-2 fieldstest points and average thickness of macular GCCparameters were taken into account to develop a new mode of macular RGCs(mRGC1).Scatterplots and linear regression then was used to examine the relationship between estimated macular RGC counts and functional/structural parameters.Area under the receiveroperating characteristic(ROC)curves(AUCs)was used to evaluate the ability of the parameters to differentiate between controls and glaucomatous eyes.Results:The macular and total estimated RGC counts showed highly significant differences among the five groups(P<0.0001).There was strong correlation between estimated macular RGC counts and GCC thickness(R2=0.807mRGC1and R2=0.827 mRGC2;P<0.001).There was strong correlation between estimated macular RGC counts and eRGC(R2=0.0.914mRGC1and R2=0.968 mRGC2;P<0.001).At early stages of damage(high macular RGC counts),changes in estimated RGC counts correspond to relatively smaller changes in MD and relatively larger changes in average GCC thickness.At advanced stages of damage,changes in estimated RGC counts correspond to relatively large changes in MD,but only small changes in average GCC thickness.Both of the area under the ROC curve of macular RGC counts and eRGC were more than 0.9,0.982(mRGC1),0.972(mRGC2)respectively(P<0.0001),eRGC was 0.992(P<0.0001),which had good diagnostic performance in the diagnosis of glaucoma.The estimated RGC counts performed fairly well in distinguishing healthy from glaucomatous eyes with no statistically significant difference between macular and total RGCs.Conclusions:The macular and total estimated RGC counts can discriminate glaucomatous from healthy eyes and various stages of the disease.There is also a good/very good correlation with both GCC thickness which gives further support to the validity of the method used for estimating macular RGC counts.Glaucomatous damage affects both macular and extramacular regions to a similar degree.At early stages of damage(high macular RGC counts),changes in estimated RGC counts correspond to relatively smaller changes in MD and relatively larger changes in average GCC thickness.At advanced stages of damage,changes in estimated RGC counts correspond to relatively large changes in MD,but only small changes in average GCC thickness.Both macular and total estimated RGC counts had good diagnostic performance in the diagnosis of glaucoma and them could be used as valid surrogates for neural losses in glaucoma.