Drugs generally affect human health in many harmful ways; however, their impact on the eyes has additional and serious consequences. These effects begin with weakened vision, as excessive drug abuse can cause direct effects on eyesight, such as increased blurriness and reduced visual acuity. The damage may extend to the optic nerve and spread through the brain to the visual center located at the back of the brain. Therefore, each type of drug has a different effect on the eyes, including: Loss of focus while looking Increased intraocular pressure Irritation and redness of the conjunctiva The image illustrates the extent of the effects of drugs on the eyes. Drug abuse may cause corneal ulcers, which can lead to loss of vision. Changes in blood pressure caused by some drugs may lead to increased intraocular pressure, which raises the risk of developing eye diseases such as glaucoma. Drugs severely affect the nerves of the eye muscles, the optic nerve, and the visual center in the brain, resulting in double vision, optic nerve atrophy, and loss of sight. In addition, drug use may cause various types of headaches, as shown in the figure below. Furthermore, drugs may damage the liver over time, causing jaundice that appears in the eyes, as clearly shown. The article will be continued in Part Two, God willing University of Al-Mustaqbal – The First and Leading Private University