Introduction: Diabetes mellitus (DM) (i.e., diabetes), a set of metabolic illnesses defined by chronically increased blood sucrose levels, is becoming more common worldwide. As a result of a pancreatic beta-cell failure, inadequate insulin is formed. Type 1 insulin is generated to efficiently apparent blood sucrose; type 2 insulin is formed to effectively clear blood glucose; type 3 insulin is produced (T2DM), characterized by insulin resistance. When the hormone fails to affect the target cells, gestational diabetes mellitus (GDM) arises while pregnant. Insulin resistance develops in pregnant women. Diabetes is the leading cause of visual defects in adults in the world. Diabetes causes problems in maximum parts of the eye, like in retina it causes retinopathy, in the lens it causes cataract, in lids- lashes the xanthelasma is more common, in conjunctiva the bacterial infections are more common as in diabetes they receive more nutrition and easy to increase, in cornea it causes keratopathy, and it is more severe it is also linked to tear function abnormality. Diabetes is a well-known significant factor for visual impairment as there are 12000 to 24000 new cases of visual loss every year. By 2030, it is expected that more than 342 million individuals worldwide will have diabetes, with the degree of diabetic consequences in various organs determining the total health burden.