Abstract
Purpose :
To evaluate the relationship between fractal dimension (Df) of retinal microvascular around macular and diabetic retinopathy(DR) in patients with type 2 diabetes mellitus (T2DM) by using optical coherence tomography angiography (OCT-A).
Methods :
Sixty-one nondiabetic eyes and 167 eyes with T2DM were evaluated. The T2DM eyes were classified into three groups: 111 eyes without DR (NDR), 43 eyes with mild non-proliferative DR (NPDR), and 13 eyes with moderate or severe NPDR. Capillary mean Df around macular within 3×3 mm was assessed quantitatively based on the OCT-A images (RTVue; Optovue, Inc., Fremont, CA, USA). Logistic regression models were used to compute odds ratios (OR) and confidence intervals (CI) for T2DM/ NPDR with adjustment for confounders.
Results :
For the diabetic groups, the mean Df in the deep vascular layers were significantly different among the groups (ANOVA, p<0.001), with NPDR patients having lower Df compared with NDR. After adjustment for age and sex (Table 1), lower Df in the diabetic patients was significantly associated with increased odds of retinopathy (OR 9.21, p<0.001) comparing the highest and lowest quartile of Df. This association remained with additional adjustment for body mass index (BMI), Mean arterial blood pressure (MABP), intraocular pressure (IOP), diabetes duration, blood glucose, HbA1c, triglyceride, total cholesterol, high density lipoprotein and low density lipoprotein (OR 32.90, p=0.002). Furthermore, the mean Df in the NDR patients were also lower compared with the nondiabetic group. Logistic regression showed there was a trend of an association of lower Df and diabetes after adjustment for age, sex, BMI, MABP, IOP (p=0.059).
Conclusions :
Lower retinal capillary Df in the deep vascular layer, representing the decreased geometric complexity of the retinal microvascular around the macular, is independently associated with early DR signs in T2DM. Fractal analysis of images acquired by OCT-A may allow quantitative measurement of early diabetic microvascular damage.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.