Abstract
Purpose: :
Previous studies suggest that persons with diabetes have decreased retinal thickness. We compared the macular thickness in persons with and without diabetes in an urban Indian population using optical coherence tomography (Stratus OCT, Carl Zeiss Meditec, Dublin, CA), and identified factors which significantly affect OCT measurements of the macula.
Methods: :
This was a population-based case-control study which included participants from the Singapore Indian Eye Study (SINES). We identified 247 participants with diabetes mellitus, which included 40 participants with diabetic retinopathy (DR) and 207 participants without DR, and 86 non-diabetic controls. Macular measurements were obtained from the right eye of the participants after pupil dilation, using the fast macular thickness scan protocol. We excluded subjects who received previous retinal laser treatment, and those with macular pathology, including macular edema.
Results: :
The mean age of the participants was 60.1 ± 10.1 years (range 44 to 83 years), and 179 (53.8%) participants were male. Participants with diabetes had an increased foveal thickness (190.47 ± 26.18 µm vs 183.84 ± 20.22, p = 0.038) compared to controls. Total macular volume was not significantly different between participants with diabetes and controls. Among persons with diabetes, those with DR had an increased foveal thickness (202.81 ± 37.79 vs 188.06 ± 22.61 µm, p = 0.002) compared to those without DR. OCT measurements of the macula did not differ significantly between diabetic participants without DR and normal controls. Factors associated with an increased total macular volume were being male (p = 0.022), younger age (p < 0.001) and an increased spherical equivalent (p = 0.005), after controlling for glycosylated haemoglobin (HbA1C), diabetes duration and mean arterial blood pressure (MABP). Male gender (p = 0.033), older age (p = 0.006) and a decreased spherical equivalent (p = 0.026) were associated with an increased foveal thickness after controlling for HbA1C, diabetes duration and MABP.
Conclusions: :
Our population-based study showed that persons with diabetes (with and without DR) have an increased foveal thickness, although total macular volume is not significantly different, as compared to non-diabetic controls. These data may aid in the interpretation of OCT findings in persons with diabetes.
Keywords: diabetes • imaging/image analysis: clinical • macula/fovea