corneal ulcer

Corneal ulcer

Definition

Defined as discontinuation in normal epithelial surface of cornea associated with mecrosis of the surrounding corneal tissue

Bacterial corneal ulcer

Etiology

• Damage to corneal epithelium

• Infection of eroded area

Pathogenesis

The development corneal ulcer is in 4 stages

1. Stage of progressive infiltration

2. Stage of active ulceration

3. Stage of regression

4. Stage of cicatrization

Clinical features

• Depends on virulence of organism, its toxins and enzymes and the response of host tissue

Symptoms • Pain • Foreign body sensation• Watering • Photophobia• Redness of eyes

Signs

• Edema of lids • Marked blepharospasm• Conjunctival chemosis• Corneal Epithelial defect• Yellowish white area of ulcer, oval or irregular in shape• Margins are swollen & over hanging • Floor covered with necrotic material • Stromal edema • Muddy iris • Small pupil • Increased IOP

Causative bacteria

• Staphylococcal aerues and steptococus pneumonia

• Pseudomonus

• Enterobacteria

General examination

• Built

• Nourishment

• Anaemia

• Immunological status

Ocular examination

• Diffused light examination

• Regurgitation test and syringing

• Biomicroscopic examination (staining with 2% fluorescein dye)

Laboratory investigation

1. TC, DC, ESR

2. Microbiological investigation (scrapping from the margins of the ulcer under LA)

a. Gram and Giemsa stain (gram +ve )

b. 10% KOH (fungal hyphae)

c. Calcofluor white (CFW) (fungal filaments)

d. Blood agar medium culture (aerobic )

e. Sabourauds dextrose agar medium (fungi)

.. contd

f. Blood agar medium (most bacteria and fungi except neisseria, hemophilus and moraxella (NHM))

g. Chocolate agar medium (for NHM)

h. Cooked meat broth (anerobic and fastidious )

i. Brain heart infusion (for aerobic & fungi)

Treatment

1. Specific treatment for the cause

2. Non specific supportive therapy

3. Physical and general measures

Specific treatment

a. Topical antibiotics

Ciprofloxacin (0.3%)

Ofloxacin (0.3%)

b. Systemic antibiotics

Ciplox (750 mg)

Non specific treatment

• Cycloplegic drugs

a. 1% atropine ointment

b. 2% homatropine eye drops

c. Systemic anagesics & NSAIDS

d. Vitamin A,B,C

Physical & general measures

a. Hot fermentation (vasodilation)

b. Dark goggles

c. Rest, good diet and fresh air

Non healing ulcer

Treatment :1. Removal of known cause

– Local (IOP concretions , foreign body)– Systemic causes (diabetes, anaemia, malnutrition,

steroids)

2. Mechanical debridgement 3. Cauterisation of the ulcer 4. Soft contact lens bandage5. Peritomy (severing of perilimbal conjunctival

vessels)

Treatment of impending perforation

1. No stain

2. Pressure bandage

3. Lowering of IOP

4. Tissue adhesive glue (cynoacrylate)

5. Conjunctival flap

6. Soft contact lens Bandage

7. Penetrating keratoplasty

Treatment of perforated corneal ulcer

• Depends on the size of perforation availability of glues

• Conjunctival flap

• Soft bandage

• Keratoplasty

Mycotic corneal ulcer

Etiology

• Filamentous fungi (Aspergillus, fusarium)

• Yeast (Candida & cryptococcus )

Mode of infection

• Injury by vegetative material

• Injury by animal dye

• Secondary fungal ulcers

Diagnosis of MCU

• Clinical manifestation

• Laboratory investigations with wet KOH, CFU grams and giemsa stain

Treatment:

• Topical antifungal (Natamocin 5%, fluconazol 2%, Nistatin 3.5 % ointment)

• Systemic tab fluconazol 2-3 wks

Non specific treatment : Same as bacterial

Viral corneal ulcers

• Most of the viruses effect the epithelium of both conjunctival and corneal

• Hence typical viral lesions constitute the viral kerato conjunctivitis

Common viral infections

• Herpes zoaster virus

• Herpes simplex virus

Mode of infection (HSV1 - By kissing, HSV2 – infected genitalia of mothers to the neonates )

Healing of corneal ulcer

• When an ulcer has become vascularised, cicatrization occurs which is carried out by the regeneration of collagen and the formation of fibrous tissue

• Bowmans membrane is never regenerated

Complications

• Thinning of entire cornea

• Scarring if the ulcer is deep

• Keratectasia, keratocele or descemetocele

• Anterior staphyloma

Preparation of fortified antibiotics

• Gentamicin 1.5 mg / ml (1.5 %) + 2ml of 40 mg gentamicin vial

• Cefazolin 50 mg/ml (5%) + 500 mg parentral antibiotic diluted with 2.5 ml sterile water added to 7.5 ml of artificial tears (stable for 24 hrs )

Acanthamoeba keratitis

Diagnosis

• Presenting symptom blurred vision and pain

Signs

• Grayish irregular epithelial surface

• Pseudendrites

• Stromal infiltrates

Investigation

• Culture with non nutrient agar

• Staining – using periodic acid schiff or calcofluor white

Treatment of acanthamoeba

• Debrigement 1

• Debrigement 2

• Topical amoebicids

• Topical steroids

• Pain control

• Keratoblasty