Higher Levels of Serum Ionic Calcium are Associated with Macular Edema in Patients with Diabetic Retinopathy.

BACKGROUND: The aim was to study the association of serum total calcium, ionic calcium, and magnesium with increases in macular thickness parameters and photoreceptor ellipsoid zone (EZ) disruption in diabetic macular edema (DME). METHODS: This study is a tertiary care center based observational cross-sectional study with sixty-six consecutive cases, divided into 3 groups of 22 cases each with no diabetic retinopathy (No DR), non-proliferative diabetic retinopathy (NPDR), and proliferative diabetic retinopathy (PDR) and a control group of 22 healthy controls. Best corrected visual acuity (BCVA) was measured on logMAR scale. Central subfield thickness (CST), cube average thickness (CAT), and EZ disruption were assessed using spectral-domain optical coherence tomography (SD-OCT). Serum total calcium, ionic calcium, and magnesium were measured using standard protocol. Data was analyzed statistically. RESULTS: Significant correlation was found between the increase in CST and the increase in serum total calcium and serum ionic calcium. Increase in CAT was significantly correlated with an increase in serum total calcium, serum ionic calcium, and a decrease in serum magnesium. Grades of EZ disruption and logMAR BCVA were also found to be significantly positively associated with serum total calcium and ionic calcium and negatively with serum magnesium. CONCLUSIONS: Increased levels of serum ionic calcium and decreased levels of serum magnesium are associated with an increase in macular thickness and EZ disruption in DME.