DME is one of the leading causes of loss of vision in people of a working age in the developed world. It affects the function of the macula, a key part of the retina which is used for central vision. In DME there are abnormal structural changes in the blood vessel walls which lead to leakage of fluid and proteins from the blood vessels. [2, 3] DME can be classified as ischaemic or exudative, based on the dominant underlying problem. In ischaemic DME, the main problem is a reduction in blood flow to the macula which causes reduced central vision and swelling of the retinal tissues in this area. [4] In exudative DME, excessive leakage of fluid from the blood vessels around the macula results in thickening or swelling of the retina and a resultant reduction in central vision. There is often a combination of ischaemia and exudation.