Chemical eye injury and immediate irrigation

Chemical injury is damage caused by contact with an acidic, alkaline or otherwise toxic substance. Household cleaners, industrial solutions, cement, solvents and incorrectly used contact-lens products can injure the surface of the eye. Concentration, temperature, duration of contact and the chemical's ability to penetrate tissue influence severity. The clinician's first useful intervention is to shorten contact time. Obtain a brief exposure account while treatment proceeds, asking another person to locate the container or safety information rather than interrupting irrigation to complete the history.

Alkalis can disrupt cell membranes and penetrate into deeper tissues; acids often produce protein coagulation that limits further penetration, although this is not a guarantee of a superficial injury. Hydrofluoric acid is an important exception and requires urgent specialist toxicology advice because fluoride can cause deep tissue and systemic effects. An explosion may combine chemical exposure with a penetrating fragment or thermal burn. Check the wider injury pattern and personal protective requirements while ensuring that time-critical eye decontamination is actually happening.

Hold the lids open gently and encourage movement of the eye so fluid reaches the exposed conjunctiva. A topical ocular anaesthetic given by a clinician can reduce blepharospasm and make flushing feasible, but looking for it must not postpone the first water. Avoid directing a forceful jet onto the cornea. Position the head to reduce contamination of the uninjured eye, protect staff from splashes and assess skin or airway exposure where relevant. Remove contact lenses promptly during irrigation when they can be reached without traumatic manipulation.

Surface pH guides ongoing washout but is not a complete measure of injury. Aim for a stable physiological, near-neutral reading using the local measurement method and comparison eye. The NHS Highland protocol checks pH at the end of irrigation, again after five minutes and, if neutral or near neutral, after twenty minutes. A pause matters because irrigant can transiently mask residual chemical. Rebound abnormality suggests persistent material or chemical release from tissues and requires renewed irrigation and inspection. No predetermined number of litres proves that decontamination is complete. The immediate minimum twenty-minute first-aid period is therefore not a universal stopping rule.

After decontamination, document visual acuity, pupils, corneal clarity, epithelial defects, conjunctival involvement and limbal perfusion. Fluorescein demonstrates areas without intact epithelium. The limbus contains cells required to renew the corneal surface; damage there predicts persistent epithelial problems. Roper–Hall and Dua classifications describe severity using different combinations of haze, limbal involvement and conjunctival injury. Record actual findings as well as any grade so that another clinician can follow change. Definitive anti-inflammatory, antimicrobial and surface-support treatment depends on this assessment and the evolution over subsequent days.