Purpose
1. To assess choroidal thickness (CT) in diabetic patients with no retinopathy;<br /> 2. To correlate CT with disease duration, systemic blood pressure (BP), glicemia, intraocular pressure (IOP) and ocular pulse amplitude (OPA).
Methods
Prospective, observational case-control study. Diabetic patients and healthy controls were both recruited from general consultation from tertiary center.<br /> A complete ophthalmological examination was performed (visual acuity, refraction, goldman applanation and dynamic contour tonometries, fundoscopy and axial lenght. CT was assessed by a non-invasive procedure using an OCT (Spectralis Heidelberg Engineering) with an enhanced depth mode (EDI) at 13 different locations (subfoveal and 3 measurements 500um appart in all 4 directions - nasal, temporal, superior and inferior). One eye per patient was included.<br /> Mean comparison and correlation between variables were explored using non-parametric tests and Spearman correlation's, respectively.
Results
90 patients were recruited (60 diabetic patients; 30 healthy controls). Both subfoveal and 1500um superior CT were significantly thicker in the diabetic group (230.1 ± 50.59 vs 258.33 ± 67.38, p=0.04; 226.03 ± 46.63 vs 257.75 ± 64.57, p=0.02, respectively). None of the other topographic region comparisons were statistically different (p>0.05). CT of diabetic patients had a negative correlation with disease duration in at least 4 locations (r between 0.25 and 0.30, p<0.05). Furthermore, CT was positively correlated with OPA in 12 points in diabetic patients but only in 4 points of the control groups.
Conclusions
There appears to be an heterogeneous thicknening of the choroid in diabetic patients with no visible signs of the disease. Moreover, this tissue may be funcionally different, as the pattern of correlations seems to differ between groups. Further studies are needed to explore these differences and the potential of this variable in the clinical setting.