MTDH and diabetes mellitus: This study showed that serum cholesterol, the AEG-1 gene's mRNA expression and AEG-1 protein are common risk factors for all varieties of DON while the blood glucose levels (FBG and 2hpp) favour the development of DP, control of diabetes (HbA1c) favours the occurrence of AION, lastly diabetes duration is more related to the presence of optic atrophy.