In 1985, the Early Treatment Diabetic Retinopathy Study (ETDRS) demonstrated that focal (direct/grid) laser photocoagulation reduces moderate vision loss from diabetic macular oedema (DMO) by 50% or more. However, further studies have shown that photocoagulation can eventually result in complications leading to loss of central vision and decreased colour vision. Thus, many newer laser machines that claim to reduce the rate of complications have been developed over the years.