Macular thickness comparison in type II diabetic patients using optical coherence tomography: A case control study

Abstract

A case control approach was done in which the primary outcome was to measure and to compare detect any significant changes in the macular thickness of normal controls Versus Type II diabetic patients or with their subgroups of with and without diabetic retinopathy and a secondary outcome to correlate the visual acuity of distance and near with central macular thickness. Two hundred ten study subjects were included in this case-control study has been conducted over a pool of overall 210 participants were further divided into 7 groups such as normal controls, no diabetic retinopathy, mild non-proliferative diabetic retinopathy, moderate non-proliferative diabetic retinopathy, severe non-proliferative diabetic retinopathy, proliferative diabetic retinopathy, clinically significant macular edema was taken and each group having 30 patients (60 eyes in each group) using spectral-domain - OCT. Selected participants enrolled using sampling size (n = k{Z+Z}× {s+s}/d) and confidence interval being capped at 95%. An automated algorithm of OCT scanned the central retinal region having a variable thickness in three concentric circles primary central circle 1 mm of the macula. Four major quadrants (superior, nasal, inferior, temporal) was scanned from center (1mm) to inner (3 mm) and an outer circle (6 mm). To evaluate the result, overall 210 participants with each group having 30 patients in 7 groups (mean age 54.54 ± 9.67 years) were analyzed by one way ANOVA and independent sampling T-test method. The results were evenly distributed in terms of gender-wise sampling, duration/severity of the disease, and changes in visual acuity. A substantially increased macular thickness (p <0.05) was observed among severe forms of diabetic retinopathy compared with the control group. This study conclude that the there is an increased in the macular thickness of all quadrants especially in PDR and CSME group which may be masked by changes in vascular permeability triggering thickening of the retinal layers from early to severe diabetic changes of the macula, using optical coherence tomography for diabetic patients Type II  with and without diabetic retinopathy. Although central macular thickness and Log Mar visual acuity distance as well as near are moderately strong correlated.