Background: Diabetes Mellitus (DM) is a chronic metabolic disease with considerable morbidity and mortality. Diabetic retinopathy (DR) and diabetic macular edema (DME) are major complications of DM and are the principal cause of vision loss among the working age group in developed countries. Optical coherence tomography (OCT) uses low-coherence interferometry to provide noncontact and noninvasive optical biopsy of the tissue morphology of the retina, making it a useful tool for detecting and managing DME. Aim of the Work: To study the effect of controlled type II DM on visual acuity (VA) and macular changes by OCT. In addition, to correlate VA to macular parameters detected on OCT retinal examination. Patients and Methods: This is a retrospective case control study that included 30 eyes of 22 controlled type II diabetic patients (group1) and 30 eyes of 19, age and sex matched healthy subjects (group 2). All diabetic patients were diagnosed as DME using OCT parameters. Correlation between central foveal thickness (CFT) and VA was done. Results: There were statistically significant differences in UCVA & BCVA between the 2 groups. The difference in the central foveal thickness (CFT) from ETDRS map of OCT between the 2 groups was statistically significant. There were statistically significant differences between CFT from ETDRS map and both UCVA & BCVA. Statistically significant differences were detected between CFT and both FBS and 2HPP levels. Furthermore, statistically significant differences were detected between BCVA and both FBS and RBS levels. Conclusion: Based on the data in our study, results pose a recommendation of regular follow up of three blood sugar-assessing parameters (FBS, 2HPP and RBS) and referring patients to ophthalmologists if abnormal values were detected. Recommendations: Using large sample size will give more valid results. In our study, we evaluated the structure of the fovea, further studies can evaluate structure using OCT and function by electrophysiology. OCT angiography also could be useful in scanning retinal vasculature.