Acid and Alkali Burns to the Eye

Introduction

• Ophthalmology consultation is mandatory for all cases.
• Chemical eye injuries are true ocular emergencies.
• Assign Category 2 triage status.
• Immediate saline irrigation is essential.

Pathophysiology

Alkali Burns

• Cause liquefactive necrosis.
• Tissue destruction continues until the agent is completely removed.
• Alkalis (and hydrofluoric acid) are more damaging than acids.

Acid Burns

• Typically cause coagulative necrosis, which limits tissue penetration (except for HFl).

Prognosis Factors

Recovery depends on:

Factor	Description
Causative agent	Type and strength of the chemical
Limbal involvement	Assessed in “clock hours”
Conjunctival damage	Measured by % of surface area affected
Corneal damage	Degree of opacity and clarity

Clinical Assessment

General Notes

• Immediate treatment before full examination is vital.
• Injury severity increases with duration of exposure.

History

1. Time and mechanism of injury
2. Type and concentration of chemical
3. First aid measures and timing

Examination

1. Blepharospasm indicates more severe injury.
2. Corneal clarity suggests lesser damage.
3. Assess vascular blanching, especially at the limbus.
4. Record visual acuity in both eyes (if possible).

Classification of Severity

• The modified Roper-Hall classification (Dua et al.) grades injuries from 1 to 6.
• Based on Limbal involvement (clock hours) and Conjunctival involvement (% of surface)

Grade	Prognosis	Clinical Findings	Conjunctival Involvement	Analogue Scale*
I	Very good	0 clock hours of limbal involvement	0%	0 / 0%
II	Good	≤3 clock hours of limbal involvement	≤30%	0.1–3 / 1–29.9%
III	Good	>3–6 clock hours of limbal involvement	>30–50%	3.1–6 / 31–50%
IV	Good to guarded	>6–9 clock hours of limbal involvement	>50–75%	6.1–9 / 51–75%
V	Guarded to poor	>9–<12 clock hours of limbal involvement	>75–<100%	9.1–11.9 / 75.1–99.9%
VI	Very poor	Total limbus (12 clock hours) involved	Total conjunctiva (100%) involved	12 / 100%

*Analogue scale records the limbal involvement in clock hours of affected limbus/percentage of conjunctival involvement. While calculating percentage of conjunctival involvement, only involvement of bulbar conjunctiva, up to and including the conjunctival fornices is considered.

Management

1. Analgesia

• Immediate use of local anaesthetic drops
• Repeat as necessary
• IV opioids and antiemetics if severely distressed

2. Irrigation

• Use isotonic saline immediately
• Minimum 30–40 minutes for severe injuries
• Start with at least 1 litre, even if prior irrigation attempted
• Morgan lens may assist
• Evert eyelids to irrigate inner surfaces

3. pH Monitoring

Tool	Notes
Universal Indicator Paper	Test forniceal space (not just saline)
Acceptable pH	6.5–8.5 (normal is ~8)
Ensure dryness	Dry eye before pH test to avoid saline contamination

4. Removal of Residual Particles

• Use cotton bud to remove visible debris

5. Topical Antibiotics

• Start empiric topical antibiotics

6. Mydriatics

Used for pain relief and to prevent posterior synechiae (refer to Therapeutic Guidelines for prescribing details.)

Drug	Duration
Tropicamide 0.5%	~6 hours
Cyclopentolate 0.5%	~24 hours
Homatropine 2%	Up to 5 days

7. Topical Steroids

• Only on advice of ophthalmologist

8. Surgical Management

• Severe cases may require corneal grafting
• Prognosis depends on initial severity

Additional Measures (Ophthalmology-directed)

• Topical Vitamin C
• Topical Citrate

Disposition

• All patients require urgent ophthalmology consultation
• Severe burns → likely admission and urgent review

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Appendix 1

Appendix 2

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References

FOAMed

• Nickson C. Ophthalmology Befuddler. Clinical Cases. LITFL
• Nickson C. The Eye In Chemical. LITFL

Publications

• Roper-Hall MJ. Thermal and chemical burns. Trans Ophthalmol Soc U K (1962). 1965;85:631-53.
• Dua HS, King AJ, Joseph A. A new classification of ocular surface burns. Br J Ophthalmol. 2001 Nov;85(11):1379-83.
• The Eye Emergency Manual, NSW Department of Health, 2nd ed. 2009