Damage tends to occur to the front of the eye. Industries use a variety of chemicals daily. However, household chemicals can be just as dangerous and must be treated cautiously. The acidity or alkalinity, called the pH, of a substance is measured on a scale from 1-14. If a substance is neither acid nor alkaline, it is neutral, and its pH number is 7.
Alkali burns are the most dangerous.
Alkalis chemicals that have a high pH penetrate the surface of the eye and can cause severe injury. In general, the higher the pH, the more damage will occur. Common alkali substances contain the hydroxides of ammonia, potassium, sodium, calcium, and magnesium. Substances you may have at home that contain these chemicals include lye, cement, lime, and ammonia. Acid burns result from chemicals with a low pH and tend to be less severe than alkali burns.