Choroidal Thickness in Diabetic Patients without Diabetic Retinopathy

Abstract

PurposeTo evaluate choroidal thickness (CT) in diabetic patients without diabetic retinopathy (DR) using enhanced depth imaging spectral‐domain optical coherence tomography (EDI SD‐OCT). To correlate CT with disease duration, systemic blood pressure (BP), glycemia, intraocular pressure (IOP) and ocular pulse amplitude (OPA).MethodsProspective, observational case‐control study. A complete ophthalmological examination was performed (visual acuity, refraction, Goldmann applanation and dynamic contour tonometries, fundoscopy and axial length). CT was assessed by a non‐invasive procedure using an EDI‐OCT (Spectralis Heidelberg) at 13 locations (subfoveal and 3 measurements 500 μm apart in all 4 directions – nasal, temporal, superior and inferior).Results180 patients were recruited: 130 diabetic patients with no DR and 50 healthy controls; one eye per patient included in the study. CT at 1500 μm above the fovea was significantly thicker in the diabetic group (239.9 ± 56 μm vs 268.2 ± 67.7 μm, p = 0.001). None of the other topographic region comparisons were statistically different (p > 0.05). In diabetic patients CT was not correlated with disease duration, BP, glycemia or IOP. CT was positively correlated with OPA in 12 points in diabetic patients (r between 0.19 and 0.27, p < 0.05) but not in the control group. CT variation coefficients in the diabetic group were statistically lower than in the control group (p < 0.01).ConclusionsThe thickening of the choroid at 1500 μm superior of the fovea in diabetic patients without DR may correspond to the diabetic choroidopathy in mid‐periphery presented before DR. Moreover, this tissue may be functionally different, as the pattern of correlations seems to differ between groups. Further studies are needed to explore these differences and the potential of the CT in the clinical setting.