Central macular thickness in diabetics without retinopathy

Abstract

Background: Diabetic maculopathy is the major cause for blindness in type 2 diabetics. Slit-lamp biomicroscopy with +90 D lens has been the traditional method for diagnosis. Neurodegenerative changes precede clinical retinopathy. Optical coherence tomography (OCT) is a newer tool for diagnosis of such subtle changes in the macula. Aim: This study aimed to compare the central macular thickness (CMT) in type 2 diabetics without clinical retinopathy and normal controls. Subjects and Methods: This prospective case–control study was conducted at a rural tertiary care center after obtaining clearance from the Institutional Human Ethics Committee. CMT was measured using spectral-domain OCT among the type 2 diabetics without clinical retinopathy and control group. CMT was correlated with duration of diabetes and glycemic control using Pearson's correlation. Results: This study included 170 patients (85 cases and 85 controls). The average age in cases and controls was 52 ± 10.2 years and 51 ± 8.1 years, respectively; this difference was statistically not significant. Duration of diabetes ranged from newly diagnosed to 15 years. Mean glycosylated hemoglobin (HbA1c) in the study and control groups were 8.93 ± 2.54% and 4.57 ± 0.56% respectively. Mean CMT in type 2 diabetics without clinical retinopathy was 198.47 ± 17.98 μm and in control group, it was 235.68 ± 11.25 μm (P = 0.00). CMT among male diabetics was thicker than that of female diabetics (P = 0.00). CMT did not correlate with duration of diabetes (r = 0.54) or with the glycemic control (r = 0.09). Conclusion: CMT was thinner among type 2 diabetics without clinical retinopathy than healthy controls. CMT did not correlate with duration of diabetes or with the glycemic control.

Keywords

• central macular thickness and glycemic control
• diabetic maculopathy
• type 2 diabetes mellitus