Principles of management of poisons in contact with eye- Ocular toxic exposure (eye contamination)

Ocular toxic exposure occurs when chemicals, biological toxins, industrial products, or household agents come into direct contact with the eye. Rapid recognition and immediate irrigation are critical because delayed treatment can result in permanent visual impairment or blindness.

Risk factors

Environmental and occupational

• Industrial chemical exposure

• Laboratory accidents

• Agricultural chemical splashes

• Mechanical and automotive work

Household exposure

• Detergents and bleaches

• Battery acid

• Cosmetic products

• Cleaning agents

Patient-related

• Contact lens use

• Delayed irrigation

• Pre-existing ocular disease

Clinical presentation

Early findings

• Lacrimation

• Photophobia

• Conjunctival redness

• Foreign body sensation

• Blepharospasm

Progressive findings

• Severe ocular pain

• Corneal clouding

• Reduced visual acuity

• Conjunctival ischemia

Late findings

• Corneal ulceration

• Corneal perforation

• Permanent blindness

Diagnostic criteria

Diagnosis is based on:

• Definite history of ocular chemical exposure

• Ocular surface pH abnormality

• Corneal or conjunctival injury

• Progressive symptoms despite initial irrigation

Investigations

• Ocular pH testing

• Visual acuity assessment

• Fluorescein staining

• Slit-lamp examination

• Orbital imaging when penetrating injury is suspected

Non-pharmacological treatment

Immediate irrigation

Emergency irrigation must begin immediately and should not be delayed for examination.

• Remove contact lenses immediately

• Irrigate with clean running water or normal saline

Duration of irrigation

• Irritant exposure: 15–20 minutes

• Acid exposure: at least 30 minutes

• Alkali exposure: at least 30 minutes and reassess for a further 30 minutes if necessary

Additional measures

• Tetracaine hydrochloride 1–2 drops may be instilled to facilitate irrigation

• Evert eyelids and remove retained particles

• Recheck ocular pH where available

• Perform fluorescein staining after irrigation

Pharmacological treatment

• Topical antibiotic eye drops

• Cycloplegics for pain relief

• Lubricating eye drops

• Vitamin C (ascorbate)

• Doxycycline to reduce corneal melting

• Short-course topical steroids under ophthalmologist supervision

• Anti-glaucoma therapy when intraocular pressure is elevated

Referral

Urgent ophthalmology referral is required for:

• Significant conjunctival injury

• Corneal epithelial defects

• Corneal opacity

• Persistent pain

• Reduced vision

• Limbal ischemia

• Any alkali burn

• Suspected globe perforation

• Cases where detailed eye examination cannot be performed

Prevention

Do's

• Use eye protection when handling chemicals

• Store chemicals safely

• Read product labels carefully

• Use child-resistant containers

Don'ts

• Transfer chemicals into beverage containers

• Remove warning labels

• Store chemicals near food

• Allow children access to hazardous products