Early eye screening detection and treatment is fundamental in managing significant complications of chronic disease, both for improving diabetic retinopathy (DR) clinical outcomes and improving the economic burdens. Early detection and subsequent treatment can substantially reduce the risk of blindness from DR. This chapter will review the screening episode, measuring visual acuity, drop instillation, contraindications, and correct camera operation. It will review problems associated with incorrect camera operation and the NHS Diabetic Eye Screening Programme (NHSDESP) standards of acceptable image quality. This will guide the screener in obtaining clear, well-centred, gradable digital images of the retina in diabetic patients with vision better than no perception of light in both eyes, as well as providing a greater understanding of issues associated with screening.