Ocular chemical injuries

1. OCULAR CHEMICAL
INJURIES

2.  INTRODUCTION
 EPIDEMIOLOGY
 MECHANISM
 CLASSIFICATION/GRADING
 MANAGEMENT

3. CHEMICAL INJURIES
 One of the true ophthalmic emergencies
 Often result in significant ocular
morbidity and generally strike young
adults in the prime of life.
 2nd
most common cause of work based
eye injuries at 12%.

4. EPIDEMIOLOGY
 2/3rd
in young males.
 2/3rd
at Workplace vs home
 Alkali > Acid
 2/3rd
are minor (gr. I & II) injuries
 In India common d/t fire cracker
injuries,lime or after accidental injury with
holi colours

5. Acid injury
 Acids dissociate into hydrogen ions and
anions in the cornea, e.g.: HCl= H+
+Cl-
 The hydrogen molecule damages the
ocular surface by altering the pH, while
the anion causes protein denaturation,
precipitation, and coagulation .
 Protein coagulation generally prevents
deeper penetration of acids.
MECHANISM

6. Alkali injury
 pH changes: increase in pH , which
saponifies the fatty acid of cell
membranes leading to cell destruction.
 Ulceration & proteolysis: Alkalies cause
stromal ulceration at two to three weeks
after injury this ulceration is though to be
due to various proteolytic enzymes.
 Collagen synthesis defects
MECHANISM

7. • Roper-Hall/ modified Hughes classification
• Degree of corneal involvement
• Limbal ischemia.
• Dua classification
• Limbal involvement (in clock hours)
• Percentage of conjunctival involvement.
 In a randomized controlled trial of acute burns, the Dua classification
was found to be superior to the Roper-Hall in predicting outcome in
severe burns. However, both classification schemes are commonly
employed in daily practice.
CLASSIFICATION OF CHEMICAL INJURIES

8. DUAS CLASSIFICATION
Gr Prognosis Clinical findings(clock
hrs of limbal
involvement
Conjunctival
involvelment
Analogue
scale
I Very good 0 clock hours 0% 0.0%
II Good ⩽3 clock hours ⩽30% 0.1-3/1-30%
III Good >3–6 clock hours >30–50% 3.1-6/31-50%
IV Good to
guarded
>6–9 clock hours >50–75% 6.1-9/51-755
V Guarded to
poor
>9–<12 Clock hours >75–<100% 9.1-
11.9/75.1-
99.9%
VI Very poor 12 clock hours involved Total
conjunctiva
(100%) involved
12/100%
A new classification of ocular surface burns: Harminder S Dua, Anthony J King,
Annie Joseph, Br J Ophthalmol 2001;85:1379–1383.

9. Dua’s classification
Grade 1 ocular surface burn. Large
corneal burn following accidental
exposure to ammonia. There is no limbal
or conjunctival involvement. Fluorescein
stained diffuse view of the cornea.

10. Dua’s classification

11. Dua’s classification
Grade 3 (5/35%) ocular surface burn
following an accident involving an
industrial alkaline chemical. Five clock
hours of the limbus and 35% of the
conjunctiva were involved.

12. Dua’s classification
 Grade 4 (7/50%) ocular surface burn
following an acid burn. Seven clock
hours of the limbus and 50% of the
conjunctiva were involved. (A) An
autolimbal transplant was first carried
out in the inferior nasal quadrant
(arrows). (B) One year after a full
thickness corneal transplant that
succeeded the autolimbal transplant
by 4 months. Arrows show the limits
of the autologous conjunctiva
attached to the peripheral corneal
strip that constituted the "autolimbal
graft." The patient has been followed
for 2.5 years and retains a clear graft.
(With the Roper Hall grading (IV) this
would carry a poor prognosis.)

13. Dua’s classification
 Grade 5 (9.5/60%) ocular surface
burn following alkali injury. Nine
and a half clock hours of the
limbus and 60% of the
conjunctiva were involved. (A)
Diffuse view of the cornea
showing extensive
conjunctivalisation and a
fibrovascular pannus. (B) The
eye 13 months after ocular
surface reconstruction with
autolimbal transplantation. (With
the Roper Hall grading (IV) this
would carry a poor prognosis.)

14. Dua’s classification
 Grade 6 (12/100%) ocular
surface burn with a "fish pond
cleaning liquid" following an
assault. The entire limbus and the
entire conjunctiva were
involved. (A) Diffuse view
showing involvement of the
entire upper and (B) lower
bulbar conjunctiva. (C) The
entire corneal surface and 12
clock hours of the limbus are
involved. This patient carries a
very poor prognosis.

15. MANAGEMENT
 Management of the case of chemical
burns can be divided into:
 Immediate / Emergency Treatment
 Early acute phase treatment
 Intermediate term treatment
 Late rehabilitation treatment

16. MANAGEMENT
 Immediate / Emergency treatment:
1. Irrigation with NS/water/BSS for atleast 30 mins. or
till pH turns neutral.
2. Eyelid immobilization with eyelid speculum or
retractor.
3. Instillation of topical anaesthesia.
4. Removal of particulate matter/debris after double
eversion of lids.

17. MANAGEMENT
 Early Acute Phase treatment:
Broadly classified into :
 Those promoting reepithelization / transdifferntiation:
Tear substitutes, Bandage soft contact lens, Fibronectin, Epidermal growth
factor, Retinoic Acid.
 Those supporting repair and minimizing ulceration:
Ascorbate, Collagenous inhibtors like sodium EDTA 0.2 M, calcium EDTA 0.2 M,
penicillum 0.2 M and 10 % to 20%acetylcystine.
 Those controlling inflammation.

18.  Early Acute Phase treatment:
Aim of treatment is to restore the cornea with normal epithelium and a clear
stroma by decreasing the inflammation and enhancing the healing.
Treatment after irrigation is as follows:
1. Topical steroids 2 hourly
(inhibits PMN proliferation and function)
2. Topical sodium citrate 10% 2 hourly
(inhibits PMN degranulation by Ca chelation)
3. Tetracycline 1% ointment QID
(inhibits collagenase enzyme by chelating with Zn)
4. Oral sodium ascorbate 500mg QID
(promotes collagen synthesis)
5. Topical sodium ascorbate 20% 2 hourly
(promotes collagen synthesis)
6. Tear substitutes 2 hourly
(promotes epithelial healing)
7. Cycloplegics TDS or BD
(relieves pain)
8. Topical/oral antiglaucoma therapy, if needed
9. Conjunctival/tenons advancement for grade-IV.
(Improves vascularization)

19. MANAGEMENT
 Intermediate Phase treatment:
 Conjunctival / Tenons advancement : It is based on the
principle of suturing vital connective tissue in the orbit to
reestablish limbal vascularity and to facilitate
epithelization.
 Tissue adhesives: They are used in small corneal perforations, whereas
an emergency patch graft or therapeutic PK is done for large
perforations.
 Amniotic membrane transplantation

20. MANAGEMENT
 Late Rehabilitation Phase:
Impending or actual perforation
1. Tissue adhesives for <1mm perforations
2. Tectonic keratoplasty
Vascularised Cornea
1. Limbal stem cell transplantation followed by
Penetrating keratoplasty (PK) or Lamellar keratoplasty (LK) after 6 months.
2. Large PK or large LK
3. Keratoprosthesis in Bilateral cases.
For symblepharon/cicatrisation of conjunctiva
Amniotic membrane transplant/mucus membrane transplant can be done.

21. REFERENCES
 Dua HS, King AJ, Joseph A. A new classification of ocular surface
burns. Br J Ophthalmol. 2001 Nov;85(11):1379-83. doi:
10.1136/bjo.85.11.1379. PMID: 11673310; PMCID: PMC1723789.
 DOS Times: Chemical Injuries of the Eye
Dr. Tishu Saxena MS, Dr. Radhika Tandon MD, DNB, FRC Ophth., FRCS
Ed, Dr. Jeewan S. Titiyal MD
 Kanski's Clinical Ophthalmology, Tenth Edition: Textbook by John
F. Salmon
 https://doi.org/10.1038/s41433-020-1026-6: Chemical eye injury:
pathophysiology, assessment and management
Harminder S. Dua ● Darren Shu Jeng Ting ● Ahmed Al Saadi ● Dalia
G. Said

22. MANAGEMENT
 Late Rehabilitation Phase:
Impending or actual perforation
1. Tissue adhesives for <1mm perforations
2. Tectonic keratoplasty
Vascularised Cornea
1. Limbal stem cell transplantation followed by
Penetrating keratoplasty (PK) or Lamellar keratoplasty (LK) after 6 months.
2. Large PK or large LK
3. Keratoprosthesis in Bilateral cases.
For symblepharon/cicatrisation of conjunctiva
Amniotic membrane transplant/mucus membrane transplant can be done.