The Application Of The Estimated Retinal Ganglion Cell Counts In Detecting Glaucoma Progression

Objectives:Calculate the estimated retinal ganglion cell counts(eRGC)by integrating the structural and functional parameters of glaucoma.Evaluate the application of the rate of eRGC loss in detecting glaucoma rogression.Methods:Observational cohort study.The study included 69 eyes of 38 patients with glaucoma in different stages.All patients received at least 5 consecutive standard automated perimetry(SAP)and optical coherence tomography(OCT)measurements,two measurements should be completed on the same day.There was a 2-year separation between the first and last measurements.Based on the parameters such as the sensitivity of the visual field(VF),the average retinal nerve fiber layer(RNFL)thickness and age of the patients,the number of RGC somas and the number of RGC axons can be derived and then evaluate the correlation between them.Finally,obtain the final eRGC of each eye by calculate the weighted average.Linear regression analysis was used to calculate the rate of the RGC loss.An eye was considered to have progressed if the slope of RGC loss was significantly faster than the age-expected decline of RGC counts(7205cells/year)with P<0.05.Estimate the rate of eRGC loss to detect glaucoma progression.Results:Baseline eRGC of the enrolled patients was 466949 + 311614.In these 69 eyes,the rate of eRGC loss in 9 eyes(13%)was higher than that of age-expected decline of RGC counts(P<0.05).The mean rate of eRGC loss of these eyes was-67022 cells/year.The mean rate of eRGC loss was-16791 cell/year(>7205 cell/year)in the eyes of patients without progression.There was a strong correlation between RGC count obtained from SAP and OCT data for the 213 eyes included in the study group and the correlation coefficient is r=0.861,P<0.01.A larger proportion of glaucomatous eyes showed progression based on the rate of RGC loss rather than based on isolated parameters from OCT(10.1%),or SAP(11.6%).There was progression of 2 eyes detected by three methods.There was progression of 2 eyes only detected by eRGC.Conclusion:The number of glaucoma progression detected by the rate of eRGC loss was higher than either by VFI alone or by average RNFL thickness alone.There was a strong correlation between RGC count obtained from SAP and OCT data for the 213 eyes included in the study group.The rate of eRGC loss in eyes of patients with ’glaucoma without progression was higher than in normal subjects.eRGC,which is integrated with the structural and functional parameters of glaucoma,is a new tool that is worthy of further study and clinical application.