A chemical burn in the eye occurs when a liquid or powdered substance contacts the ocular surface, initiating a rapid chemical reaction that causes tissue damage. This injury is a time-sensitive medical emergency where every moment of exposure increases the risk of permanent vision loss. The severity of the damage depends on the chemical’s composition, concentration, and duration of contact with the eye tissues. The primary goal of immediate treatment is to remove the chemical agent swiftly.
Immediate Emergency Steps
The most impactful action following a chemical splash to the eye is to begin immediate and continuous irrigation. Flush the eye with a large volume of clean, lukewarm tap water or saline solution for an extended period. Do not delay this step to search for specialized eyewash or to remove contact lenses; flush first, then deal with contacts.
While flushing is underway, contact emergency medical services or have someone else call for help. The irrigation must continue for a minimum of 15 to 30 minutes to ensure the chemical is adequately diluted and removed from the eye’s surface.
To irrigate effectively, hold the eyelid open with your fingers to ensure the water reaches all parts of the eye and the under-surface of the lids. If only one eye is affected, tilt the head so the water flows away from the unaffected eye to prevent cross-contamination. Direct a gentle stream of water from a faucet, shower, or clean container onto the eye, asking the person to move their eye in all directions to thoroughly rinse the entire surface.
Understanding Chemical Severity
The potential for long-term damage is largely determined by whether the chemical is an acid or an alkali, also known as a base. Alkaline substances, such as lye, ammonia, and drain cleaners, are responsible for the most severe injuries because they penetrate tissues deeply and quickly. The hydroxyl ions in alkalis cause a process called liquefaction necrosis, which saponifies the fatty acids in cell membranes, effectively dissolving tissue and allowing the chemical to travel into the deeper structures of the eye.
In contrast, acidic substances, like vinegar and car battery fluid, typically cause a mechanism known as coagulation necrosis. The hydrogen ions cause proteins on the eye’s surface to denature and coagulate, creating a protective barrier that often limits the acid’s ability to penetrate the deeper cornea and internal eye structures. However, highly concentrated or hydrofluoric acid can still cause catastrophic damage. Understanding this difference explains why an alkali burn may initially appear less painful than an acid burn, yet it is often much more destructive.
Professional Medical Intervention
Upon arrival at a medical facility, the immediate priority remains the removal of the caustic agent, even if prolonged flushing has already occurred. Medical staff will continue copious irrigation, often using specialized buffered solutions or sterile saline, while periodically checking the pH of the ocular surface. The goal is to return the eye’s pH to a neutral range of 7.0 to 7.2.
Once the pH is normalized, a comprehensive ophthalmic assessment begins, including checking visual acuity and measuring intraocular pressure. A special dye, fluorescein, is used to stain the eye and reveal the extent of corneal and conjunctival damage under a slit lamp microscope. Any remaining particles or dead tissue (necrotic debris) may be carefully debrided to promote healing.
Specific medications are then administered to manage the injury and prevent complications. Topical antibiotics are prescribed to guard against secondary infection. Cycloplegic drops are used to relax the ciliary muscle, reducing painful muscle spasms and light sensitivity. In cases of significant inflammation, topical corticosteroids may be used, though their usage must be carefully monitored due to the potential risk of corneal melting.
Recovery and Long-Term Care
The recovery phase begins once the acute chemical exposure is neutralized and the eye is stabilized. Healing can be a long process; mild injuries resolve within a few weeks, while severe burns require months or even years of management. The primary concern during this period is preventing complications that can lead to permanent vision impairment.
Severe burns can result in the loss of limbal stem cells, which are responsible for renewing the corneal surface, potentially leading to chronic epithelial defects. This deficiency can cause the conjunctiva to grow over the cornea, a process called corneal vascularization and scarring, which severely limits vision. Secondary issues such as persistent dry eye, elevated intraocular pressure leading to glaucoma, and cataract formation may also develop.
Adherence to the prescribed regimen of medications, which often includes lubricating eye drops and anti-inflammatory agents, is necessary for a positive outcome. Regular follow-up appointments with an ophthalmologist are necessary to monitor healing, manage intraocular pressure, and detect early signs of complications. For the most severe injuries, surgical interventions, such as corneal transplantation or limbal stem cell grafts, may be necessary to restore the ocular surface and potentially recover lost vision.