Abstract
Purpose :
Vitamin D has anti-angiogenic and anti-inflammatory effects. Vitamin D receptors are expressed in inner retinal layers, photoreceptors and retinal pigment epithelium (RPE). Correlation of serum vitamin D levels with quantitative [central subfield thickness (CST), cube average thickness (CAT)], cross sectional [disorganization of retinal inner layers (DRIL) and ellipsoid zone (EZ)] and topographic parameter (RPE) on spectral domain optical coherence tomography (SD-OCT) was studied in diabetic retinopathy (DR), for the first time.
Methods :
A tertiary care center-based cross sectional study was undertaken according to the tenets of the Declaration of Helsinki and institutional review board clearance. Sixty six consecutive cases of type 2 diabetes mellitus [no retinopathy (No DR; n=22); non-proliferative DR (NPDR; n=22); proliferative DR (PDR; n=22)] and healthy controls (n=22) between the ages of 40 and 65 years were included, after sample size calculation. Physician-friendly grading systems were created for DRIL, EZ and RPE abnormalities on SD-OCT. DRIL was graded: grade 0, DRIL absent; grade 1, DRIL present. EZ disruption was graded: grade 0, intact EZ; grade 1, focal EZ disruption; grade 2, global EZ disruption. RPE alterations were graded on segmentation map: grade 0, no RPE alterations; grade 1, RPE alterations in up to two quadrants and grade 2, RPE alterations in more than two quadrants. Serum vitamin D was analyzed using chemiluminescence immunoassay technique. Statistical analysis was done using Pearson correlation, Student’s t test, ANOVA, chi-square (χ2) test and univariate ordinal logistic regression analysis.
Results :
Mean serum vitamin D levels (ng/ml) were: No DR=23.36±2.00, NPDR=17.88±1.86, PDR= 14.07± .21, and controls = 25.11±1.59. Low serum vitamin D levels significantly correlated with severity of retinopathy (p<0.001), logMAR visual acuity (r=0.50, p<0.001), CST (r=0.36, p<0.001), CAT (r=0.41, p<0.001), DRIL (r=0.35, p<0.01), EZ disruption (r=0.40, p<0.001) and RPE alterations (r=0.37, p<0.001). Univariate analysis revealed that vitamin D, visual acuity, CST, CAT, DRIL, EZ and RPE are significant predictors of severity of DR .
Conclusions :
Low serum vitamin D levels correlate with increased severity of DR and with changes in DRIL, EZ and RPE alterations on SD-OCT.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.