Relationship between optic disc parameters and visual field loss

Objective To evaluate the relationship between mean sensitivity(MS)and mean defect(MD)in each optic disc parameter by visual field examination.Methods Selection was performed among 201 cases(402 eyes)that underwent Heidelberg retinal tomography(HRT)and visual field examination during 2 weeks.Among them,the 103 cases(161 eyes)with MD2 dB and whose refractive error and fundus appearance did not meet exclusion criteria were enrolled.HRT parameters(disc area,rim area,cup-disc ratio,mean retinal nerve fiber layer(RNFL)thickness and cross-sectional area)and visual field parameters(central 30 degree),including MS and MD were evaluated.Results Visual field parameters were MS(20.34±5.79)dB and MD(6.94±5.47)dB,optic disc parameters were optic cup area(1.02±0.59)mm2,optic cup volume(0.29±0.25)mm3,mean optic cup depth(0.29±0.13)mm,maximum optic cup depth(0.71±0.25)mm,cup-disc ratio 0.40±0.20,horizontal cup-disc ratio 0.64±0.18,vertical cup-dics ratio 0.54±0.25,average RNFL thickness(0.23±0.10)mm,RNFL cross-sectional area(1.29±0.61)mm2.MS significantly correlated with optic cup area(r=-0.413,P0.001)and optic cup volume(r=-0.267,P=0.001).Similarly,MD also significantly correlated with optic cup area(r=0.405,P0.001)and optic cup volume(r=0.279,P0.001).However,MS and MD did not significantly associate with mean/maximum optic cup depth(all P0.05).MS and MD significantly associated with optic cup and disc area ration,horizontal and vertical cup-disc ratio(all P0.01).MS and MD also significantly related with mean RNFL thickness and RNFL cross sectional area(all P0.01).MS did not significantly associated with optic disc area(r=-0.124,P=0.117),but positively associated with optic rim area(r=-0.383,P0.001).Similarly,MD did not significantly associated with optic disc area(r=0.127,P=0.108),but positively associated with optic rim area(r=-0.370,P0.001).Conclusions For the cases with visual field loss,the optic cup area is more important than optic cup depth for clinic doctors.Optic rim,cup-disc area ratio,horizontal and vertical cup-disc ratio,RNFL thickness and cross section area is related with visual field loss.