OBJECTIVE
To explore the association of choroidal thickness variations in type 2 diabetes mellitus (T2DM) patients with diabetic retinopathy (DR) at different stages.
METHODS
A total of 161 patients with T2DM were included in this study, from October 2012 to June 2014. According to Early Treatment Diabetic Retinopathy Study (ETDRS) criteria, the patients were divided into 5 groups: non-DR without diabetic macular edema (DME) group(DR-/DME- group, 45 eyes), nonproliferative diabetic retinopathy (NPDR) without DME group(NPDR+/DME- group, 58 eyes), proliferative diabetic retinopathy (PDR) without DME group (PDR+/DME- group, 12 eyes), NPDR with DME group (NPDR+/DME+ group, 41 eyes), PDR with DME group (PDR+/DME+ group, 5 eyes). Meanwhile, 60 normal subjects were enrolled as the control group. All study subjects received optical coherence tomography enhanced depth imaging (EDI-OCT) examination to detect and compare subfoveal choroidal thickness at different stages of DR.
RESULTS
Mean SFCT was (271 ± 36), (270 ± 35), (262 ± 38), (244 ± 36), (229 ± 35) µm respectively in control, DR-/DME-, NPDR+/DME-, PDR+/DME-, NPDR+/DME+ groups. The SFCTs of PDR+/DME- and NPDR+/DME+ group were statistically lower than that of control group (P=0.004, P=0.001). The SFCT of PDR+/DME- group was lower than that of DR-/DME- group (P=0.003), and there was also a significant difference of SFCT between NPDR+/DME+ and NPDR+/DME- group (P=0.001). There was linear correlation between SFCT and the logMAR best-corrected visual acuity (r=0.397, P<0.01), but the SFCT was independent of diabetic duration, fasting blood glucose, HbA1c, axial length, diastolic blood pressure (DBP) and systolic blood pressure SBP (r=-0.024, 0.159, 0.089, 0.036, 0.143, 0.057, all P>0.05). There was no significant difference of SFCT among different DME types (F=0.071, P>0.05).
CONCLUSION
The SFCT decreased with increasing severity of DR. To monitor the SFCT in T2DM patients may be helpful to evaluate the severity of DR and provide a new treatment conception.