Choroidal Thickness and Systemic Examination in Diabetic Patients without Diabetic Retinopathy
Abstract
Purpose
The choroidal circulation receives nearly 95% of ocular blood flow and it is essential for a normal retinal structure and function. Recently, several clinical studies showed a variation in choroidal thickness (CT) even before the presence of diabetic retinopathy (DR), which the meaning remains uncertain and questionable. Our objective was to analyze and correlate the CT with the disease duration, systemic blood pressure (SBP) and analytic evaluation.
Methods
Prospective, observational case-control study. A complete ophthalmological examination was performed, including dynamic contour tonometry and axial length. 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 500 μm apart in all 4 directions – nasal, temporal, superior and inferior). The SBP was measured and an analytical evaluation was performed, including glycemia, glycosylated hemoglobin – HbA1c, lipid parameters, renal function, ionogram and microalbuminuria. Correlation between variables was explored using Spearman correlations.
Results
The study included 65 diabetic patients without DR (36 females; mean age 67.23 ± 9.08 years), with an average disease duration of 90.42 ± 81.82 months. The CT didn't showed a correlation with disease duration, SBP, glycemia, HbA1c, renal function, lipid parameters, homocysteinemia, natremia or microalbuminuria. However, the CT was positively correlated with potassium and chlorine serum levels in 5 points, with statistic significance (r between 0.26 and 0.31, p < 0.05).
Conclusions
CT may be positively influenced by serum levels of potassium-chlorine in diabetic patients but not in healthy controls. These abnormal CT relationships can be detected even with no visible DR. Further studies are needed to explore these differences.
