Manasvini Sharma1, Ashish Chander2, Rupali Chopra3, Nitin Batra4
BACKGROUND
Macular oedema is one of the important causes of vision impairment in patients with diabetic retinopathy. In diabetic retinopathy, single measurements of central foveal thickness using OCT correlate with visual acuity. The purpose of the study is to assess Central Macular Thickness (CMT) in diabetics with and without diabetic retinopathy and to compare CMT within different stages of retinopathy.
MATERIALS AND METHODS
A total of 500 eyes of 250 diabetic subjects and 150 eyes of 75 age and gender matched controls were included. Complete ophthalmological examination was done and they were divided into 5 subgroups according to the diabetic retinopathy grading. OCT scanning was performed using Nidek RS-3000 Lite OCT, which generated a topographical map of the macula. Central macular thickness was defined as the average thickness in the central 1 mm diameter. Other parameters like body mass index, duration of diabetes and glycated haemoglobin levels of last 3 months were also assessed.
RESULTS
A statistically significant difference was observed in the mean central macular thickness between the study and control group (p<0.001). Among the subgroups, subjects in the CSME group showed maximum CMT (394.0±105.3 μm) while minimum CMT was seen in no diabetic retinopathy group (248.3±21.8 μm). Central macular thickness was seen to increase progressively with increasing stages of diabetic retinopathy. CMT in no DR and mild NPDR differed significantly with each of the other subgroups (p<0.001). The difference in central macular thickness between moderate NPDR subgroup and severe NPDR (p=0.431) and PDR subgroup (p=0.106) was not statistically significant. On regression analysis, increased duration of diabetes and glycated haemoglobin correlated with higher CMT.
CONCLUSION
Subclinical macular thickening was observed in diabetics, which increased with increasing stages of diabetic retinopathy without evidence of any clinically significant macular oedema.
