Corneal burns – forms, treatment
Eyeball consists of three tunics (layers). External tunic is made of the cornea (anterior), and sclera (posteriorly). The second tunic of the eyeball is the uveal (vascular, nutritional membrane of eye) which consists of the iris (anterior), ciliary body and choroid (posterior). The retina is the third tunic of the eyeball and is the nervous tunic.
Cornea in addition to the protection role, fulfills its optical role due to its transparency, leaving light rays enter the eye. Among trauma diseases that can affect the cornea, burns are include. Corneal burns are very common injuries and very serious because of their consequences (scar formation). These burns also affect the conjunctiva (is a transparent, mucous membrane, glossy, lining the back of the eyelids and front of the eyeball).
Corneal burns can be caused by both physical agents and chemical agents.
Among the physical agents that cause corneal burns the most significant are UV rays and thermal physical agents (gases or vapors, overheated liquid, molten metal).
UV radiation is absorbed by the cornea in large amounts and produce lesions in the superficial layers. Such burns may occur in welders or in those who are exposed to the action of coartem lamps.
Clinically, corneal burns caused by ultraviolet radiation are characterized by intense lacrimation, photophobia, blepharospasm (abnormal, involuntary muscle contraction of the eyelid muscle of variable duration), increased eye pain, congestion, conjunctivitis.
Treatment aims to relieve the eye pain and for this purpose there must be administered anesthesia drugs as eyewash (to be applied to the eye, specifically in the conjunctiva). You can use an antiseptic and healing medication.
Prevention of these burns is by wearing masks and safety glasses.
Burns caused by the thermal physical agents (gases or vapors, overheated liquid, molten metal) are accompanied by lacrimation, blepharospasm, increased pain and important damage of the eyelid.
Treatment of these burns aims to limit inflammatory reactions, avoid superinfection and stimulate the reepithelization.
Chemical agents cause more serious injuries than physical agents. Chemical burns can be caused by a large number of substances. The severity of burns depends on the chemical composition, the amount that comes into contact with the cornea and the time of contact with the substance.
Among the chemical agents that cause corneal burns are acids (sulfuric acid, hydrochloric acid, acetic acid) and bases (sodium and potassium hydroxide).
Acid burns are somewhat more benign than the base burns, because after base burns the penetration of new quantities of caustic substance in-depth is still active after several days after from accident, while the acid burns as a result of necrosis coagulation, is achieved a kind of barrier that prevents penetration of the substance in-depth.
Symptoms of chemical burns vary from lacrimation, blepharospasm and pain, even loss of visual acuity.
Treatment of burns should be done urgently, first act is to remove the substance with a cotton swab, with a forceps or a curette if the substance adheres to the cornea.
Step 1: removal of the substance with cotton swab, step 2: washes with warm water or if possible with neutralizing agents (for acid burns use sodium bicarbonate solution 1%, for base burns use weak acid like boric acid 1-3 %, acetic acid 1%).
In the next phase of treatment the aim is to relieve the pain (with analgesics), avoid superinfection (local antiseptic medications and application of healing substances).
Sometimes, in addition to medical treatment is required surgery to remove the substance from the tissue, but most often for removing the necrotic tissue.