by Shadi Awwad, MD

A. Introduction:
Chemical injury to the eye can be of two kind:
A. Acidic
B. Alkali (basic)
Acids are usually twice less common as a source of injury than alkali. They are usually found in car batteries and industrial cleaners (H2SO4), silicone production, glass polishing, gasoline alkylation(HF), Vinegar(acetic acid), chrome plating industry(Cr2O3)
Alkali are found in cleaning agents and fertilizers(ammonia NH3), drain cleaners(Lye, NaOH), sparklers(Magnesium hydroxide Mg(OH)2), plaster, cement(lime, Ca(OH)2)
Alkali are usually more damaging to the human eye than acids, with the exception of some strong acids like hydrofluoric acid (HF)

B. Complications of chemical eye injury:
               Injury to the outermost layer of the cornea (the epithelium) that can be irreversible and necessitating surgical procedures (such as limbal cell transplantation)
Corneal perforation: that can be acute with the strong alkali like ammonia (NH3) and lye ( NAOH), or late in onset (up to 6weeks after the injury,  when corneal melting takes over corneal regeneration)
Corneal scarring and subsequently poor vision, that will ultimately become established occur at a later stage
High intra-ocular pressure that might occur at time of injury or later with subsequent risk of  glaucoma.
Infection that usually establishes over the denuded cornea.

C. Treatment:
Immediate:
      -As soon as the injury happens, run to the nearest water source and promptly irrigate the involved eye with running  waterfor about 15 minutes. Mere washing is not sufficient.
      -See the closest eye specialist to have your eyes adequately irrigated and assessed.
      -have the chemical pamphlet or bottle with you if available for the physician to know which kind of injury      he's dealing with, and which compound: this affects treatment and prognosis
       -Injury is usually graded into I, II, III, IV according to severity and limbal cell affection (limbal cells being to precursors of the outermost layer of the cornea. They are usually precious because they don't divide.
First 3-6 weeks:
     -Treatment includes steroids eye drops for the first 10 days, together with antibiotics, +/- tetracycline, citrate and ascorbate(vitamin  C)eyedrops, and Vitamin C tablets and sometimes Doxycycline antibiotic tablets as well.
       -Close follow-ups are to be expected.
       -Grade I and II usually heal without complications.
       -Grade III and IV usually require surgery on top of the medical treatment.
              -Surgeries include Corneal transplantation, "glue" instillation, stem cell transplantation, amniotic membranes, tenoplasty, keratoprosthesis