Your eyes are delicate structures that work due to a complex interplay between blood vessels, nerves, muscles, and glands. When one piece of this chain breaks down, the health of the entire eye is at risk.
Alcohol: Heavy drinkers have a higher risk for macular degeneration and cataracts. Some also develop involuntary eye movements.
Marijuana: This drug can impact your ability to track items with your eyes as they move across your field of vision. You may also have trouble discriminating between colors, and you may be sensitive to the sun. With long-term use, those problems could be permanent.
Cocaine: This drug is toxic to the cornea, and it can cause ulcers. That can happen to people who smoke or snort the drug. It can also change blood vessel structures in the eye and lead to inflammation or bleeding. Those can cause permanent vision loss.
Heroin: This drug can cause inflammation in the eye. If you inject it, you can also push germs into your body and your eyes.
Methamphetamine: This drug can cause a spike in blood pressure, which can damage your eyes. That could persist even when you get sober. Meth can also cause corneal ulcers, especially if you snort or smoke the drug.