Retinal vasculature measurement
tortuosity
A CANON CR-2/Plus/AF RX non-mydriatic retinal camera is being used to obtain retinal images. Two images of each eye are being taken (macular centred and disc centred), following a standard protocol. Image quality will be continuously monitored throughout the study. Images will be graded using fully automated software providing measures of arteriolar and venular diameter and tortuosity. The refractive status of the eyes are being assessed using aCanon RK-F2 Autorefractometer.