The Change Of Subfoveal Choroidal Thickness In Nonproliferative Diabetic Retinopathy Patients

Objective To investigate the change of subfoveal choroidal thickness (SFCT) and relationshipbetween SFCT and the severity of the diabetic retinopathy using enhanced depth imaging opticalcoherence tomography (EDI-OCT).Methods A total of93patients (164eyes) of type2diabetes mellitus (DM) were selected fromMarch2012to February2013，including34males59eyes and59females105eyes. They were amean age of (56.80±5.81) years old ranging from50to69years old. They had no retinopathyand choroidopathy except diabetic retinopathy, diseases affecting blood flow in the eyes andserious complications of other systems. The patients with DM were divided into four groupsaccording to international classification standards of DR: nondiabetic retinopathy (NDR) group(64eyes), mild non-proliferative diabetic retinopathy (NPDR) group (33eyes), moderate NPDRgroup (37eyes), and severe NPDR group (30eyes). Another group as normal control washealthy and enrolled10males18eyes and15females24eyes. They were a mean age of(56.80±5.81) years old ranging from50to69years old. The eyes of all patients were examinedfully including EDI-OCT, which was measuring SFCT. That the change of SFCT and therelationship between SFCT and the severity of the diabetic retinopathy was analyzed in the DRgroups and the control group by one-way ANOVA. All diabetic patients were requested to askand record the DM duration, to measure the fasting blood glucose, blood pressure then calculatethe mean arterial pressure, and axial length using A ultrasonography. The correlations wereanalyzed with SFCT and diabetic duration, fasting plasma glucose, mean arterial pressure, andaxial length of diabetic patients by Pearson and Spearman correlation analysis.Results The mean SFCT of the DM patients were224.24±42.10μm (ranging from130.5to340.0μm). The SFCT of normal control group was276.77±48.07μm (ranging from141.5to415.0μm). There were negative linear correlation between SFCT of all patients and the severityof retinal lesions (rs=-0.555, P=0.000). There were statistically differences compared betweenthe DM group and the control group (P<0.05), and also significant differences statisticallyamong the SFCT of the NDR, mild NPDR, moderate NPDR, severe NPDR groups (P<0.05). And LSD-t test showed that there were statistically differences among the SFCT of all diabeticgroups except NDR and mild NPDR groups (P<0.05). There was negative correlation betweenSFCT and DM duration (rs=-0.332, P=0.001). But the SFCT was independent of fasting plasmaglucose (rs=-0.123, P=0.221), mean arterial pressure (rs=-0.116, P=0.248), and axial length (rs=-0.018, P=0.855).Conclusion SFCT was thinner in the eyes of the DM patients than the normal controls. Therewere differences about SFCT in the NDR, mild NPDR, moderate NPDR, severe NPDR patients.And the SFCT was gradually thinning with the severity of diabetic retinopathy.