Relationship between parameters of optic disc and visual field defect in early primary glaucoma

Objective To detect relationship between topographic parameters of the optic disc from Heidelberg Retinal Tomograph(HRT-II) and Humphrey 750 perimeter in early primary glaucoma.Methods 79 subjects were examined with HRT-II and Humphrey 750 perimeter.These included 49 primary glaucoma patients and 30 normal individuals.Both eyes were included in the study,optic nerve head damage per eye was corresponding to respective visual field defect independently.To compare difference of topographic parameters of optic disc among normal,chronic angle-closure glaucoma(CACG),primary open-angle glaucoma(POAG) and normal tension glaucoma(NTG) subjects,and analysis correlation between topographic parameters of the optic disc and mean defect of visual field respectively.The topographic parameters of the optic nerve head were undergone stepwised discriminant analysis and the discriminant function was established.The sensitive diagnostic parameters of glaucoma were screened.Results The topographic parameters of optic disc,including cup area(CA),disk area(DA),rim area(RA),cup volume(CV),rim volume(RV),cup/disk area ratio(CDAR),linear cup/disk ratio(LCDR),mean cup depth(MCD),maximum cup depth(max CD),cup shape measure(CSM),height variation contour(HVC),mean RNFL thickness(MRNFLT),RNFL cross sectional area(RCSA) and mean defect(MD) values,showed significant(P0.01) difference between the above 4 groups.There was a linear relationships between LCDR and MD in normal eyes,DA,CA and MD in POAG group,CA,RA,CV,CDAR,HVC and MD in NTG group.The sensitive diagnostic parameters were CV and HVC.The regression equation was MD = 4.475 × CV + 5.338 × HVC-0.480.The discriminant function was D = 2.767 + 0.312 × RA + 3.731 × RV + 4.294 × MRNFLT-3.668 × CSM-4.024 × HVC.Conclusion The examination of the topographic parameters of optic discs,together with Humphrey 750 Results is valuable in diagnosis of early glaucoma.