Metabolic cataracts are related to the metabolism of the lens. As blood sugar increases, the glucose content of the lens increases, which increases the activity of its aldose reducing enzymes. Glucose is converted into sorbitol, and sorbitol accumulates in the lens, increasing the osmotic pressure. The lens absorbs water, causing fiber swelling and degeneration, and finally produces turbidity. Many systemic diseases, especially endocrine disorders, are often accompanied by different types of cataracts, namely metabolic cataracts. Abnormal biochemistry in the internal environment leads to cataract formation, which is more common in cases of congenital metabolic abnormalities. Therefore, the understanding of cataracts related to metabolic diseases is of great significance not only to ophthalmology, but also to the entire clinical evidence collection and differential diagnosis.