Chemical (alkali and acid) injury of the conjunctiva and cornea is a true ocular emergency and requires immediate intervention. Epidemiology:>-Chemical injuries to the eye represent between 11.5%-22.1% of ocular traumas. etiology:-Chemical injuries occur as a result of acid, alkali, or neutral agents.Alkalis being responsible for 60%. pathophysiology:-Alkali agents are lipophilic and therefore penetrate tissues more rapidly than acids.the damaged tissues then secrete proteolytic enzymes, which lead to further damage.Acids are generally less harmful than alkali . coagulated proteins act as a barrier to prevent further penetration . Symptoms & signs:-Pain,Lacrimation,Photophobia,Blepharospasm Grading of severity:=1) Roper-Hall (modified Hughes) classification 2) Dua classification MANAGEMENT:-Emergency treatment Medical treatment Surgical treatment

1. CHEMICAL INJURY
DR RAHUL MAHALA
DNB OPHTHALMOLOGY
BOKARO GENERAL HOSPITAL, BOKARO
JHARKHAND ( INDIA )

2. CHEMICAL INJURY
• Chemical exposure to any part of the eye or eyelid may result in a chemical eye
burn.
• Chemical (alkali and acid) injury of the conjunctiva and cornea is a true ocular
emergency and requires immediate intervention.
• Chemical injuries to the eye can produce extensive damage to the ocular surface
and anterior segment leading to visual impairment and disfigurement.

3. EPIDEMIOLOGY
• Chemical injuries to the eye represent between 11.5%-22.1% of ocular traumas.
• 2/3 these injuries occur in young men and children age 1-2 years are particularly
at risk.
• The vast majority of the injuries occur in the workplace as a result of industrial
accidents.
• Minority of injuries occur in the home or secondary to assault.
• Alkali found more commonly in building materials and cleaning agents and occur
more frequently than acid injuries.

4. INTERNATIONAL CLASSIFICATION OF DISEASES
• ICD-9-CM
• 940.2 alkaline chemical burn to cornea and conjunctiva.
• 940.3 acid chemical burn to the cornea and conjunctiva.
• 372.06 chemical conjunctivitis.
• ICD-10-CM
• T26.60XA Corrosion of cornea and conjunctival sac, unspecified eye, initial
encounter.

5. ETIOLOGY
• Chemical injuries occur as a result of acid, alkali, or neutral agents.
• Alkalis being responsible for 60%.
• Common causes:-

6. PATHOPHYSIOLOGY
• 1)Alkali:-
• Alkali agents are lipophilic and therefore penetrate tissues more rapidly than
acids.
• They saponify the fatty acids of cell cell membranes.
• penetrate the corneal stroma and destroy proteoglycan ground substance and
collagen bundles.
• the damaged tissues then secrete proteolytic enzymes, which lead to further
damage.

7. • 2)Acids:-
• Acids are generally less harmful than alkali substances.
• They cause damage by denaturing and precipitating proteins in the tissues they
contact.
• The coagulated proteins act as a barrier to prevent further penetration (unlike
alkali injuries).
• Exception :- hydrofluoric acid, where the fluoride ion rapidly penetrates the
thickness of the cornea and causes significant anterior segment destruction.

8. • Damage by severe chemical injuries tends to progress as below:
• 1) Necrosis of the conjunctival and corneal epithelium with disruption and
occlusion of the limbal vasculature.
• 2) Loss of limbal stem cells may lead to conjunctivalization and vascularization of
the corneal surface, or persistent corneal epithelial defects with sterile corneal
ulceration and perforation.
• 3) Longer-term effects include ocular surface wetting disorders, symblepharon
formation and cicatricial entropion.
• 4) Deeper penetration causes the breakdown and precipitation of
glycosaminoglycans and stromal corneal opacification.

9. • 5) Anterior chamber penetration results in iris and lens damage.
• 6) Ciliary epithelial damage impairs secretion of ascorbate, which is required for
collagen production and corneal repair.
• 7) Hypotony and phthisis bulbi may ensue in severe cases.
• Healing:-
• 1) The epithelium heals by migration of epithelial cells originating from limbal
stem cells.
• 2) Damaged stromal collagen is phagocytosed by keratocytes and new collagen
is synthesized.

10. SYMPTOMS & SIGNS
• Pain
• Lacrimation
• Photophobia
• Blepharospasm
• Diminution of vision
• Eye lid edema
• Chemosis
• Corneal abrasions

11. GRADING OF SEVERITY
• Two major classification schemes for corneal burns.
• 1) Roper-Hall (modified Hughes) classification
• 2) Dua classification

12. ROPER-HALL (MODIFIED HUGHES) CLASSIFICATION
• The Roper-Hall classification is based on the degree of corneal involvement and limbal ischemia.
• Grade 1 is characterized by a clear cornea (epithelial damage only) and no limbal ischemia
(excellent prognosis).
• Grade 2 :-shows a hazy cornea but with visible iris detail and less than one-third of the limbus
being ischemic (good prognosis).
• Grade 3 :-manifests total loss of corneal epithelium, stromal haze obscuring iris detail and
between one-third and half limbal ischemia (guarded prognosis).
• Grade 4 :-manifests with an opaque cornea and more than 50% of the limbus showing ischaemia
(poor prognosis).

13. GRADE 1 GRADE 2
GRADE 4GRADE 3

15. DUA CLASSIFICATION
• Based on an estimate of limbal involvement (in clock hours) and the percentage
of conjunctival involvement.

16. EFFECTS OF OCULAR SURFACE BURN

17. MANAGEMENT
• Emergency treatment
• Medical treatment
• Surgical treatment

18. EMERGENCY TREATMENT
• A chemical burn is the only eye injury that requires emergency treatment without
formal clinical assessment.
• Copious irrigation:- crucial to minimize duration of contact with the chemical
and normalize the pH in the conjunctival sac as soon as possible.
• The speed and efficacy of irrigation is the most important prognostic factor.
• Tap water should be used if necessary to avoid any delay, but a sterile balanced
buffered solution, such as normal saline or Ringer lactate, should be used to
irrigate the eye for 15–30 minutes or until the measured pH is neutral.

19. • Double-eversion of the upper eyelid should be performed so that any retained
particulate matter trapped in the fornices is identified and removed.
• Debridement of necrotic areas of corneal epithelium should be performed at the
slit lamp to promote re-epithelialization and remove associated chemical
• Admission to hospital will usually be required for severe injuries to ensure
adequate eye drop instillation in the early stages.

20. MEDICAL TREATMENT
• Patients with mild to moderate injury (Grade I and II) have a good prognosis and
can often be treated successfully with medical treatment alone.
• The aims of medical treatment are to enhance recovery of the corneal epithelium
and augment collagen synthesis, while also minimizing collagen breakdown and
controlling inflammation.

21. STANDARD TREATMENTS
• Antibiotics:-
• A topical antibiotic ointment like erythromycin ointment four times daily can be
used to provide ocular lubrication and prevent superinfection.
• Stronger antibiotics (e.g. a topical fluoroquinolone) are employed for more severe
injuries (e.g. Grade II and above).
• Cycloplegic agents:-
• Such as atropine or cyclopentolate can help with comfort.

22. • Steroid drops:-
• In the first week following injury, topical steroids can help calm inflammation and
prevent further corneal breakdown.
• In mild injuries, topical prednisolone can be employed four times daily.
• In more severe injuries, prednisolone can be used every hour.
• After about one week of intensive steroid use, the steroids should be tapered
because the balance of collagen synthesis vs. collagen breakdown may tip
unfavorably toward collagen breakdown.
• Artificial tears:-and other lubricating eye drops, preferably preservative free,
should be used generously for comfort.

23. OTHER TREATMENTS
• Ascorbic acid:-
• A cofactor in collagen synthesis and may be depleted following chemical injury.
• Used as a topical drop (10% every hour) or orally (two grams, four times daily in
adults).
• Reverses a localized tissue scorbutic state and improves wound healing, promoting
the synthesis of mature collagen by corneal fibroblasts.
• Citric acid:-
• A powerful inhibitor of neutrophil activity and reduces the intensity of the
inflammatory response.
• Topical sodium citrate 10% is given 2-hourly for about 10 days, and may also be given
orally (2 g four times daily).

24. • Tetracyclines:-are effective collagenase inhibitors and also inhibit neutrophil
activity and reduce ulceration
• If there is significant corneal melting and can be administered both topically
(tetracycline ointment four times daily) and systemically (doxycycline100 mg
daily tapering to once daily).
• Acetylcysteine 10% six times daily is an alternative anticollagenase agent given
topically.
• Symblepharon formation should be prevented as necessary by lysis of
developing adhesions with a sterile glass rod or damp cotton bud.
• IOP should be monitored, with treatment if necessary; oral acetazolamide is
recommended to avoid adding further to the ocular surface burden.
• Periocular skin injury may require a dermatology opinion.

25. LATE SEQUELAE OF CHEMICAL INJURY
Conjunctival bands Symblepharon

26. Cicatricial entropion Corneal scarring
Keratoprosthetics

27. SURGICAL TREATMENT
• Early surgery may be necessary to promote revascularization of the limbus,
restore the limbal cell population and re-establish the fornices.
• 1) Advancement of Tenon capsule with suturing to the limbus is aimed at re-
establishing limbal vascularity to help to prevent the development of corneal
ulceration.
• 2) Limbal stem cell transplantation from the patient’s othereye (autograft) or from
a donor (allograft) is aimed at restoring normal corneal epithelium.
• 3) Amniotic membrane grafting to promote epithelialization and suppression of
fibrosis.
• 4) Gluing or keratoplasty may be needed for actual or impending perforation.

28. • Late surgery may involve:
• 1) Division of conjunctival bands and symblepharon.
• 2) Conjunctival or other mucous membrane grafting.
• 3) Correction of eyelid deformities such as cicatricial entropion.
• 4) Keratoplasty for corneal scarring should be delayed for at least 6 months and
preferably longer to allow maximal resolution of inflammation.
• 5) A keratoprosthesis may be required in a very severely damaged eye.