Eye irrigation is the crucial first step in the treatment of chemical injuries to the eye. Chemical burns are among the most urgent of ocular emergencies. The procedure dilutes the chemical (acid or base) and, if accomplished within seconds or minutes after the event, can decrease the damage caused by the chemical and improve the long-term prognosis.

Chemical burns are more common in adult patients and may occur as industrial accidents, in agricultural work, or in the household. In children, household accidents are the most common source of ocular chemical exposure. Ideally, irrigation of the eye begins immediately at the location where the incident occurred and is continued by emergency medical technicians (EMTs) and then completed in the hospital emergency department. The procedure can be performed by the parent, the patient, a bystander, EMTs, nurses, and physicians (1,2,3,4,5,6).

Chemical injuries to the eye can occur accidentally or unintentionally in all age groups and also may occur intentionally in adolescents. Because household agents are a major cause of chemical burns of the eye, active toddlers and preschoolers are at particular risk (Table 48.1).

The conjunctiva is a thin, transparent mucous membrane that covers the posterior surface of the lids (the palpebral conjunctiva) and the anterior surface of the sclera (the bulbar conjunctiva) (see Fig. 45.1). It is continuous with the skin at the lid margin and with the corneal epithelium at the limbus (sclerocorneal junction). The palpebral conjunctiva is firmly adherent to the tarsus. At the superior and inferior margins of the tarsus, the conjunctiva is reflected posteriorly at the superior and the inferior fornices and attaches to the sclera to become the bulbar conjunctiva, which is loosely attached to the orbital septum in the fornices and the sclera. The fornices and the medial and lateral canthi are locations where chemicals can pool or become trapped, especially if in the solid state. The eye, therefore, must be irrigated well in these difficult-to-reach areas (7).

The cornea is a transparent, avascular membrane that functions as a refracting and protective window through which light rays pass en route to the retina. The epithelium comprises the outer layer of the cornea, and the endothelium lines the anterior chamber of the eye. Chemical or physical damage to the endothelium of the cornea is far more serious than epithelial damage and can cause marked swelling, scarring, and loss of transparency, which can lead to loss of vision. Therefore it is vital to limit damage to the cornea during chemical exposure by prompt and thorough irrigation.

The irrigation process is more difficult in a child who is uncooperative. Such a child may need to be immobilized for the procedure; however, sedation is rarely indicated.

The severity of a chemical burn varies depending on the nature of the chemical, its volume, its concentration, the duration of contact, and the reaction with tissue components. Gases are less injurious than liquids or solid particles.

Alkaline substances are usually more damaging to the ocular structures than acids. Acids with pH of 2.5 or less coagulate and precipitate tissue proteins, which create a physical barrier against further penetration. Buffering by surrounding tissue proteins also helps localize damage to the initial area of contact. Exceptions include burns from hydrofluoric acid and from acids containing heavy metals, which rapidly penetrate
the cornea. Organic solvents result in epithelial damage and do not penetrate into deeper structures.

An alkali burn is usually more severe because it thromboses blood vessels, denatures collagen, and damages cell membranes by saponification, a process by which the alkali reacts with fats to form soaps, thereby allowing further penetration of the alkali into the eye (1,3,4,5,6,8,9).

Any suspected contact with the eyes by a caustic or irritant warrants irrigation. Children with acute onset of burning, pain, itch, or redness should have the affected eyes irrigated for possible chemical exposure.

Small foreign bodies of the conjunctiva that are not embedded often can be removed with irrigation. Children with foreign body sensation in the eye without a visible foreign body also may benefit.

For moderate or severe burns, irrigation should begin immediately on arrival to the ED. Consultation with ophthalmology should occur promptly while instituting treatment. Irrigation is indicated in children with suspected chemical exposure of the eye even if the parent or prehospital care providers have already irrigated.