Morphology of retinal nerve fiber layer in diabetic patients by optical coherence tomography / 中华实验眼科杂志

ABSTRACT

Background Conventional studies showed that the primary pathological change of diabetic retinopathy (DR) is retinal microangiopathy.However,recent studies found that the disorder of visual function appears prior to retinal microangiopathy in diabetic patients.Thereby,this findings can not be explained by conventional view.Objective The aim of the study was to find the change of retinal nerve fiber layer (RNFL) by frequency domain optical coherence tomography(OCT) in the diabetic patients without retinal microangiopathy and with non-proliferative DR (NPDR) and investigate the relationship between the change of RNFL thickness and DR.Methods Sixty eyes of 56 patients with 2 type diabetes mellitus were enrolled in Shanxi Eye Hospital from October 2012 to September 2013.The patients were divided into the non-diabetic retinopathy (NDR) group (30 eyes of 26 patients) and NPDR group (30 eyes of 30 patients) depending on the findings of fundus fluorescine angiography (FFA) according to the DR International Clinical Classification System.Thirty normal eyes of 30 age-and gendermatched healthy volunteers were included as controls.RNFL thicknesses around optical disc and macular zone were measured by OCT,including average RNFL thickness in 360°,superior nasal,superior temporal,temporal,inferior temporal,inferior nasal and nasal RNFL thicknesses.The measuring results were compared between the three groups.Results The total average thickness values of RNFL around the optic disc for the NDR group,NPDR group and the control group were (97.46-± 8.65) μm,(100.69 ± 16.35) pm and (109.22 ± 8.69) μm,respectively,and the parameters in the NDR group and NPDR group were significantly lower than those in the normal control group (P=0.001,0.006).The RNFL thicknesses were thinning at the superior temporal,temporal,inferior temporal,inferior nasal quadrants around optical disc in NDR group compared with the normal control group (P=0.001,0.001,0.001,0.010),and RNFL thickness values of all the quadrants were decresed in the NPDR group compared with the normal control group,and significant differences were seen in superior temporal and nasal quadrants (P =0.001,0.046).The total average thickness values of RNFL around macular zone for the NDR group,NPDR group and the normal control group were (33.47±3.39),(36.81±3.21) and (38.18±2.16) μm,and parameters in the NDR group was significantly lower than that in the normal control group (P =0.001).The RNFL thicknesses of all the quadrants around macular zone in the NDR group were thinned in comparison with the normal control group (all at P＜0.01),and the RNFL thicknesses at the superior nasal,superior temporal and temporal quadrants were significantly decreased in comparison with the normal control group (P=0.026,0.015,0.001).Conclusions The thinning of the RNFL thickness occurs prior to retinal microangiopathy in diabetic patients,and it may be an early pathological stage for DR.