A Follow-up Study Of Retinal Nerve Fiber Layer Thickness And Visual Field In The Progress Of Primary Open-angle Glaucoma

Objective:To observe the changes of visual field（VF）and retinal nerve fiber layer（RNFL）thickness in patients with primary open-angle glaucoma（POAG）,analyze the related factors of visual field progress,and further explore trend of RNFL thickness in different degrees of baseline VF defect,then provide guidance for more effective use of VF and RNFL in following-up of POAG patients.Methods:A prospective cohort study was conducted to select POAG patients from September 2017 to April 2018 in the West Coast ophthalmology department of the Affiliated Hospital of Qingdao University.A total of 39 patients（77 eyes）were divided into three groups based on the severity of glaucomatous VF loss:the first group included patients with mild baseline VF defects（mild group;n=21 eyes）;the second group included patients with moderate VF defects（moderate group;n=18 eyes）;the third group included patients with severe baseline VF defects（severe group;n=38 eyes）.All subjects were tested as the following order:（1）naked eye and best corrected visual acuity（BCVA）test;（2）Octopus 900 automatic perimetry;（3）measurement of intraocular pressure（IOP）with Goldman applanation tonometer;（4）fundus examination after full mydriasis;（5）inspection by Heidelberg optical coherence tomography（OCT）:measure the average thickness of the ring RNFL section around the optic disc.The IOP、MD value RNFL thickness of and the subjects were measured and recorded once every 3 months.All the groups were followed up postoperatively for 18 months.In the study of factors related to VF damage,stepwise regression method was used to select independent risk factors,and logistic regression analysis was used to analysis multiple factors.Simple linear regression analysis was used for the anylysis of RNFL thickness changes in different degrees of baseline VF defects.Results:1.Factors related to VF progress:Patients with no change in RNFL thickness had no relationship with VF progress（P>0.05）;further slight thinning of RNFL thickness was related to VF progress（P<0.05）;further obvious thinning of RNFL thickness was significantly related to VF progress（P<0.05）.The degree of baseline VF defect was related to VF progress.Compared with the mild baseline VF defect,the moderate baseline VF defect was more related to VF progress（P<0.05）;compared with the mild baseline VF defect,the severe baseline VF defect was not significantly related to VF progress（P>0.05）.2.The changes of RNFL thickness in different degrees of baseline VF defects were studied:（1）the changes of RNFL thickness were different among the three groups with different degrees of baseline VF defects;（2）the change trend of mean RNFL thickness with time in different groups was different,the specific equations are as follows:y_mild=84.604-0.088x_mild;y_moderate=68.059-0.082x_moderate;y_severe=48.495-0.015x_severe;（3）in order to further verify the trend of the average RNFL thickness over time in different groups,further data processing was carried out:it was found that the trend of the average RNFL thickness thinning in different groups was different(y’_mild=-0.031+0.089x’_mild;y’_moderate=-0.093+0.085x’_moderate;y’_severe=-0.058+0.017x’_severe).Conclusion:1、In this study,RNFL thinning was related to VF progression.During follow-up;moderate baseline VF defect was most related to VF progression,followed by mild and severe was the least.2、The thickness of RNFL changed linearly with time,and the rate of RNFL thinning was different in patients with different baseline VF defects.3、In patients with mild baseline VF defect,RNFL thinned rapidly,and the follow up can mainly relies on structural examination such as RNFL;in patients with moderate baseline VF defect,the most relevant with VF progress,and the speed of RNFL thinning tends to be slower,the follow-up could depends on regular VF and RNFL examination;in patients with severe VF defect,RNFL thinned the slowest,and the follow-up mainly relies on other high level structural examinations.