Treatment of corneal ulcer

 corneal ulcer treatment

[A] Clinical evaluation
Each case with corneal ulcer should be subjected to:
1. Thorough history taking to elicit mode of onset, duration of disease and severity of symptoms.

2. General physical examination, especially for built, nourishment, anaemia and any immunocompromising disease.

3. Ocular examination should include:
i. Diffuse light examination for gross lesions of the lids, conjunctiva and cornea including testing for sensations.
ii. Regurgitation test and syringing to rule out lacrimal sac infection.
iii. Biomicroscopic examination after staining of corneal ulcer with
  2 per cent freshlyprepared aqueous solution of fluorescein dye or sterilised fluorescein impregnated filter paper strip to note site, size, shape, depth, margin, floor and
vascularization of corneal ulcer. On biomicroscopy also note presence of keratic precipitates at the back of cornea, depth and contents of anterior chamber, colour and pattern of iris and condition of crystalline lens.

[B] Laboratory investigations
(a) Routine laboratory investigations such as haemoglobin, TLC, DLC, ESR, blood sugar, complete urine and stool examination should be carried out in
each case.
(b) Microbiological investigations. These studies are essential to identify causative organism, confirm the diagnosis and guide the treatment to be instituted. Material for such investigations is obtained by scraping the base and margins of the corneal ulcer (under local anaesthesia, using 2 percent xylocaine) with the help of a modified Kimura spatula or by simply using the bent tip of a 20 gauge hypodermic needle. The material obtained is used for the following investigations:
i. Gram and Giemsa stained smears for possible identification of infecting organisms.
ii. 10 per cent KOH wet preparation for identification of fungal hyphae.
iii. Calcofluor white (CFW) stain preparation is viewed under fluorescence microscope for fungal filaments, the walls of which appear bright apple green.
iv. Culture on blood agar medium for aerobic organisms.
v. Culture on Sabouraud's dextrose agar medium for fungi.

[C] Treatment
I. Treatment of uncomplicated corneal ulcer
Bacterial corneal ulcer is a vision threatening condition and demands urgent treatment by identification and eradication of causative bacteria.

Treatment of corneal ulcer can be discussed under three headings:
1. Specific treatment for the cause.
2. Non-specific supportive therapy.
3. Physical and general measures.
1. The specific treatment
(a) Topical antibiotics. Initial therapy (before
results of culture and sensitivity are available)
should be with combination therapy to cover
both gram-negative and gram-positive
organisms.
It is preferable to start fortified gentamycin (14
mg/ml) or fortified tobramycin (14mg/ml)
eyedrops along with fortified cephazoline (50mg/
ml), every ½ to one hour for first few days and
then reduced to 2 hourly. Once the favourable
response is obtained, the fortified drops can be
substituted by more diluted commercially
available eye-drops, e.g. :

• Ciprofloxacin (0.3%) eye drops, or
• Ofloxacin (0.3%) eye drops, or
• Gatifloxacin (0.3%) eye drops.

(b) Systemic antibiotics are usually not required.
However, a cephalosporine and an aminoglycoside
or oral ciprofloxacin (750 mg twice daily)
may be given in fulminating cases with
perforation and when sclera is also involved.

2. Non-specific treatment
(a) Cycloplegic drugs. Preferably 1 percent atropine
eye ointment or drops should be used to reduce
pain from ciliary spasm and to prevent the
formation of posterior synechiae from secondary
iridocyclitis. Atropine also increases the blood
supply to anterior uvea by relieving pressure
on the anterior ciliary arteries and so brings
more antibodies in the aqueous humour. It also
reduces exudation by decreasing hyperaemia
and vascular permeability. Other cycloplegic
which can be used is 2 per cent homatropine
eye drops.

(b) Systemic analgesics and anti-inflammatory
drugs such as paracetamol and ibuprofen relieve
the pain and decrease oedema.
(c) Vitamins (A, B-complex and C) help in early
healing of ulcer.

3. Physical and general measures
(a) Hot fomentation. Local application of heat
(preferably dry) gives comfort, reduces pain
and causes vasodilatation.
(b) Dark goggles may be used to prevent
photophobia.
(c) Rest, good diet and fresh air may have a
soothing effect.

II. Treatment of non-healing corneal ulcer
If the ulcer progresses despite the above therapy the following additional measures should be taken:
1. Removal of any known cause of non-healing
ulcer. A thorough search for any already missed
cause not allowing healing should be made and
when found, such factors should be eliminated.
Common causes of non-healing ulcers are as
under:
i. Local causes. Associated raised intraocular
pressure, concretions, misdirected cilia,
impacted foreign body, dacryocystitis,
inadequate therapy, wrong diagnosis,
lagophthalmos and excessive vascularization
of ulcer.
ii. Systemic causes: Diabetes mellitus, severe
anaemia, malnutrition, chronic debilitating
diseases and patients on systemic steroids.
2. Mechanical debridement of ulcer to remove
necrosed material by scraping floor of the ulcer
with a spatula under local anaesthesia may hasten
the healing.
3. Cauterisation of the ulcer may also be considered
in non-responding cases. Cauterisation may be
performed with pure carbolic acid or 10-20 per
cent trichloracetic acid.
4. Bandage soft contact lens may also help in
healing.
5. Peritomy, i.e., severing of perilimbal conjunctival
vessels may be performed when excessive corneal
vascularization is hindering healing.
III. Treatment of impending perforation
When ulcer progresses and perforation seems

imminent, the following additional measures may help
to prevent perforation and its complications:
1. No strain. The patient should be advised to
avoid sneezing, coughing and straining during
stool etc. He should be advised strict bed rest.

2. Pressure bandage should be applied to give
some external support.

3. Lowering of intraocular pressure by
simultaneous use of acetazolamide 250 mg QID
orally, intravenous mannitol (20%) drip stat, oral
glycerol twice a day, 0.5% timolol eyedrops twice
a day, and even paracentesis with slow evacuation
of aqueous from the anterior chamber may be
performed if required.

4. Tissue adhesive glue such as cynoacrylate is
helpful in preventing perforation.

5. Conjunctival flap. The cornea may be covered
completely or partly by a conjunctival flap to
give support to the weak tissue.

6. Bandage soft contact lens may also be used.

7. Penetrating therapeutic keratoplasty (tectonic
graft) may be undertaken in suitable cases, when
available.

IV. Treatment of perforated corneal ulcer
Best is to prevent perforation. However, if perforation
has occurred, immediate measures should be taken
to restore the integrity of perforated cornea.
Depending upon the size of perforation and
availability, measures like use of tissue adhesive glues,
covering with conjunctival flap, use of bandage soft
contact lens or therapeutic keratoplasty should be
undertaken. Best is an urgent therapeutic
keratoplasty.