Corneal Ulceration and Perforation

Question 1

What are some causes of corneal ulcers?

Answer 1

-Trauma
-Corneal abrasion due to adnexal disease
-Tear film deficiency
-Exposure Keratitis
-Infection

Question 2

What is the order of ulcer to corneal perforation?

Answer 2

Acute superficial ulcer
Mid-stromal ulcer
Deep stromal ulcer
Descemetocele
Corneal Perforation

Acute can become chronic

Acute, mid-stromal and deep can heal (Need stroma left in the eye)

Question 3

Under normal circumstances how long does it take corneal ulcers to heal?

Answer 3

7-10 days (can be faster)

Question 4

What diagnostics should you run if you think you may have a corneal ulcer?

Answer 4

Always - search for underlying cause and a Schirmer teat test

Specific indications: Corneal culture and corneal cytology

Usually: Fluorescein stain

Question 5

What are some risk factors for corneal ulcers?

Answer 5

-Is tear production normal?
-Can and does the animal blink normal?
-Brachycephalic breed (exophthalmos) and pathologic exophthalmos
-Adnexal abnormalities
-Infection?

Question 6

What are some signs of corneal ulcer?

Answer 6

-Injected Sclera
-Yellow/hypopyon in cornea
-Corneal Edema

Question 7

What are some causes of delayed corneal healing?

Answer 7

-Corneal infection
-Unresolved source of corneal abrasion
-Keratoconjunctivitis Sicca
-Exposure Keratitis
-Neurotrophic Keratitis
-SCCED (Boxer ulcer, indolent ulcer)

Question 8

What are the 2 causes of corneal infection?

Answer 8

Primary - Herpesvirus
Secondary - bacterial and fungal, progressive destruction cornea, stroma, increased size and depth

Question 9

What is entropion?

Answer 9

Inward rolling of the eyelids causing hairs to abrade the cornea
-Conformational and spastic

Question 10

What is distichia?

Answer 10

Single or multiple abnormal hairs protrude from meibomian gland opening of eyelid
- Symptoms vary and age considerations

Question 11

What is an ectopic cilia?

Answer 11

Abnormal hairs protruding through the conjunctival surface of eyelid
-Symptomatic
-Common in young dogs
-Toy breed commonly effected

Question 12

What is keratoconjunctivitis Sicca?

Answer 12

-Common cause corneal ulcer and delayed healing in dogs
-Mucopurulent ocular discharge, conjunctival hyperemia, vascularizing keratitis
-ID with Schirmer Tear Test

Question 13

What is exposure Keratitis?

Answer 13

-Conformational exophthalmos
-Inability to blink due to facial paralysis
-Exophthalmos due to orbital disease
-Buphthalmos due to glaucoma
-Touch eyelid and see if they can blink over the whole thing

Question 14

What is Neurotrophic Ketatitis?

Answer 14

-Loss of corneal sensation = spontaneous non-healing ulceration
-Opthalmic branch trigeminal nerve
-Uncommon

Question 15

What is SCCED?

Answer 15

-Spontaneous Chronic Corneal Epithelial Defect
-Chronic non-healing superficial corneal ulcer - no underlying cause determined
-Middle-aged dogs
-Boxer ulcer, indolent ulcer, refractory ulcer, recurrent erosion

Question 16

Do you treat medially or surgically for each of the listed?
Acute Superficial
Mid-Stromal
Deep Stromal
Descemetocele
Corneal Perforation
Chronic Superficial

Answer 16

Acute Superficial - Medical
Mid-Stromal- Medical
Deep Stromal - Medical/Surgical
Descemetocele -Surgical
Corneal Perforation -Surgical
Chronic Superficial - Surgical

Question 17

What are the goals of medical therapy for corneal ulcerations?

Answer 17

-Prevent/control infection
-Prevent/control collagenolysis
-Increased patient comfort
-Promote corneal healing
Use antibiotics on all ulcers - don’t stop until epithelized = no stain

Question 18

What bacteria commonly causes melting ulcers?

Answer 18

Pseudomonas

Question 19

What are a majority of the ulcers encountered in practice?

Answer 19

Superficial (Acute)

Question 20

What are the diagnostics, treatment and follow up for acute superficial ulcers?

Answer 20

Diagnostics: rule out underlying conditions

Treatment:
-Borad spectrum antibiotics BID/TID
-Topical atropine SID/BID
-Analgesic PRN (NSAID)

Follow up
-Recheck every 2-3 days
-Fluorescein stain to monitor

Question 21

What are the diagnostics, treatment and follow up for chronic superficial ulcers?

Answer 21

Chronic - haven’t healed in 7-10 days

Diagnostics - underlying reason for non-healing

Treatment - medical or surgical - ID underlying issue

Question 22

What are the diagnostics, treatment and follow up for SCCED?

Answer 22

Chronic clinical course, lack ID cause, clinical appearance

Question 23

What are clinical characteristics of SCCED?

Answer 23

-Chronic superficial corneal ulcer
-Epithelial Lip (fluorescein stain)
-Variable corneal pain and vascularization
-Change in size, wont heal completely with medical alone
-Rarely become infected

Question 24

What is the pathogenesis of SCCED?

Answer 24

-Not fully understood
-Hyalinized acellular anterior corneal stroma prevent corneal epithelial adhesion
-Epithelial non-adherence usually extend well beyond obvious region of ulcer

Question 25

What is the treatment for SCCED?

Answer 25

-Epithelial debridement (Numb and push on it with a cotton swab)
-Surgical - anterior stromal puncture (Grid keratotomy, Burr Keratotomy)
-Superficial keratectomy
-3rd eyelid flap or contact lens
-topical antibiotics until healed (solution vs ointment)
-E-collar may be required
Debridement mandatory - topical anesthetic alone, dry cotton swab, debride vigorously
-Ulcer may appear enlarged
-Debridement alone will not ensure healing
-Anterior Stromal Puncture - grid or burr keratotomy (penetrate hyalinized anterior corneal stroma, 1 collagen)

Question 26

How do you perform a grid keratotomy?

Answer 26

-Use a 25 gauge needle
-Lightly scratch across ulcer bed
-Begin and end in normal epithelium
-Place scratches 1 mm apart

Question 27

How do you perform a Burr Keratotomy?

Answer 27

Dremel like tool, post op infection higher

Question 28

How do you manage a keratotomy postop?

Answer 28

-Apply topical antibiotic 3-4 times daily until healed
-90% heal in 10-14 days
-3rd eyelid flap or contact Lense
-E-collar
-Repeat procedure may be needed

Question 29

What are your follow up recommendations for SCCED?

Answer 29

-Recheck 1x week
-Not healed 2-3 weeks surgical treatment repeated
-Don’t debride for at least 2-3 weeks following surgery (6 week for complete development of epithelial adhesion complexes)

Question 30

What causes SCCED in cats?

Answer 30

Feline Herpesvirus
-Debridement may help or cause corneal sequestrum formation

Question 31

What are the diagnostics and treatment for Mid-stromal Ulceration?

Answer 31

Diagnostics: Investigate underlying factors, corneal culture and sensitivity, corneal cytology

Treatment:
-Topical antibiotic, broad spectrum every 4-6 hours, solutions preferred
-Protease inhibitors (tetracycline and autogenous serum e 4-6 hours, topical atropine, analgesia)

Follow up: recheck every 24 hours then 48hrs

Question 32

What are the diagnostics, treatment and follow up for deep stromal ulcers or melting ulcers?

Answer 32

Diagnostics: investigate risk factors, corneal culture and sensitivity, corneal cytology

Treatment:
-topical antibiotics, broad spectrum antibiotics 2-4 hours
-Protease inhibitor - tetracycline, autogenous serum 2-4 hr

Follow-up:
Hospitalize and recheck ever 24 hours

Question 33

What are the diagnostics, treatment and follow up for a Descemetocele?

Answer 33

Surgical Case
-Medical management- deep ulcer
-Diagnostics: corneal cytology or culture, ulcer edged, Schirmer tear test
-Surgical treatment: Conjuctival flap, corneoconjuctival transposition
topical antibiotics, proteolytic inhibitors and e-collar

Follow up - recheck 1-3 weeks post op, discontinue antibiotic 3 week post op, trim flap pedicel 4-6 week post op

Question 34

What are the diagnostics, treatment and follow up for corneal perforation?

Answer 34

Surgical condition
Diagnosis - history, culture and radiograph

Post-operative
-Topical broad spectrum antibiotic 4-6 hr
-Topical atropine 6-8hr
-Systemic broad spectrum antibiotics
-Systemic anti-inflammatory
-E-collar