How long should the eye be irrigated?

At least fifteen minutes, and thirty for an alkali — caustic soda, lime, cement, ammonia. Irrigation takes priority over everything else.

Should an acid be neutralised with an alkali, or the reverse?

No. The reaction releases heat and worsens the burn. Irrigate with water, abundantly.

Are alkali burns more serious?

Yes. They saponify membranes and keep penetrating for hours, whereas an acid coagulates proteins and limits its own progression.

Chemical splash in the eye: what is decided in the first ten minutes

There are few situations in ophthalmology where the outcome depends on what the person present does before any doctor arrives. Chemical burn is one of them. Immediate irrigation largely determines what will remain of the eye.

Irrigate, at once, for a long time

Irrigate before calling, before looking for the product name, before going anywhere. With whatever water is available: tap, shower, bottle, saline if you have it. Lids held open with the fingers, water running from the inner corner outwards, moving the eye in every direction.

At least fifteen minutes, thirty if the product is an alkali. That is very long when actually doing it — most real irrigations last two minutes, which is not enough. Remove contact lenses if present, but without interrupting irrigation to look for them.

Do not attempt to neutralise: pouring an acid on an alkali burn produces an exothermic reaction that worsens the injury. Water, in quantity, is the best treatment.

Why alkalis are worse than acids

An acid coagulates surface proteins, and that coagulation forms a barrier which limits its own penetration. An alkali does the opposite: it saponifies cell membranes and keeps advancing into the stroma, then into the anterior chamber, over several hours.

That is why caustic soda, lime, cement, ammonia and drain cleaners are the most feared. Lime adds a particular difficulty: its grains lodge in the conjunctival fornix and keep releasing alkali until they are removed one by one.

What happens next, in hospital

Irrigation is continued and the surface pH measured, then rechecked until it normalises. Any grains are removed. Examination assesses the extent of epithelial loss and above all limbal ischaemia — the zone where the corneal stem cells reside: it determines long-term prognosis more than the initial appearance of the cornea.

Treatment combines corticosteroids, antibiotics, cycloplegics, lubricants, and an anti-melting protocol — vitamin C topically and systemically, doxycycline, sometimes N-acetylcysteine — intended to prevent digestion of collagen by the proteases released in the following days.

The late risk

A severe burn is not judged on day one. Two complications appear later: stromal melting, within the first two weeks, and limbal stem cell deficiency, months later, in which the cornea is progressively covered by opaque, vascularised conjunctival tissue. It is this last situation that calls for limbal stem cell grafting.

When to seek care without delay. Any chemical splash in the eye is an emergency. Irrigate immediately for fifteen to thirty minutes, then go to an eye casualty department, taking the product packaging with you. Do not wait until the next day, even if the pain settles after irrigation.

Frequently asked questions

How long should the eye be irrigated?: At least fifteen minutes, and thirty for an alkali — caustic soda, lime, cement, ammonia. Irrigation takes priority over everything else.
Should an acid be neutralised with an alkali, or the reverse?: No. The reaction releases heat and worsens the burn. Irrigate with water, abundantly.
Are alkali burns more serious?: Yes. They saponify membranes and keep penetrating for hours, whereas an acid coagulates proteins and limits its own progression.