Diabetic retinopathy is one of the leading causes of blindness worldwide. We propose a low cost postable smartphone-based decision support system for initial screening of diabetic retinopathy using image analysis and machine learning techniques. We attach a smartphone to a direct handheld ophthalmoscope, where the phone captures fundus images as seen through the opthalmoscope. Through this mobile eye-examination system, we envision making the early screening of diabetic retinopathy accessible, especially where dedicated ophthalmology centers are expensive.