OPTHALMOLOGY 4 Flashcards
which 2 layers of corneal anatomy does not stain with fluorescein?
epithelium
descemets membrane
What is a corneal ulcer?
full thickness defect of the epithelium,
exposing underlying stroma
what is the difference between:
*superficial ulcer
*deep ulcer
*descemetocoele
*perforated ulcer
superficial: only epithelium is lost. heals <7 days
deep: ulcer is deeper than epithelium. involves stroma. >7days
descemetocoele: ulcer reached descemet’s membrane
perforated ulcer: full thickness corneal defect [due to it touching aqueous humour, may see dispersed oedema in eye]
how do superficial ulcers heal?
slide and divide ADD MORE
Which type of ulcers go through avascular healing?
vascular healing?
avascular: ulcers with stromal loss[neutrophils, collagen]
vascular: deep/chronic/infected
[will have blood vessels on the cornea]
what causes scar formation during corneal ulcer healing?
which species gets this more?
new collagen is disorganised
(dogs>cats)
these are signs of what condition?
pain (blepharospam)
discharge
increased lacrimation
cornela oedema
irregular surface contour
neurovascularisation&cell infiltration
reflex uveitis
corneal ulcer
what is uveitis?
inflammation within the eye
what are some causes of corneal ulcers
trauma, foreign body
hair trauma
suture trauma
infection
KCS
exposure keratopathy (inadequate eye protection)
ruptured epitheilal bulla
corneal cholestrol/calcium deposit
describe what a corneal ulcer would look like when caused by an ectopic cilia
linear small ulceration
usually young dogs
usually upper eyelids
will have some stain uptake during a flurescent flush
what is exposure keratopathy?
central corneal damage due to inadequate protection of cornea by eyelids/third eyelid. CN V, VII paralysis or prominent globe
how can you differentiate the types of corneal ulcers in practice: superficial vs descemetocole?
stain does not stick ot the membrane. therefore, center of lesion will not have stain
Which drug family should NOT be used in corneal uclers?
steroids
what are steps to perform a corneal cytology?
anaesthesia of cornea
rolll cytobrush on cornea along edges of ulcers
roll swab onto slide, stain, microscope
what are most commonly seen gram + bacterial infections?
gram -?
+: staphylococci, streptococcus
-: pseudomonas, E. Coli
as a general rule, what drug should be used if rods are present in a corneal ulcer?
cocci?
cocci: chloramphenicol
rods: ofloxacin
what is ketatomalacia
edges of ulcer appear gelatinous
can progress rapidly
“melting ulcer”
treatment of SIMPLE corneal ulcers
chloramphenicol drops
analgesia
lubricant
atropine
e-collar
when does a simple corneal ulcer become a “complicated” corneal ulcer?
if it fails to heal within 7 days
then underlying reason for failure must be adressed
what are 4 potential reasons that an ulcer is a “coplicated” ulcer?
-is actually a SCCED
-infection
underlying cause has not been found
-patient is immunocompromised
when should a corneal ulcer be referred?
severely malacic, depth >50% of stroma, descemetocoeles
What is the typical meds regime for a stromal corneal ulcer?
-antibiotic drops
-ant-collagenase
-analgesia
-topical atropine
what is the top choice for an anti-collagenase drug for a corneal ulcer?
autologous serum/plasma
these are signs of what condition?
acutely painful
yelp in pain, keep eye completely closed
excessiv etearing below ulcer
site often plugged with clotted aqueous/haemorrhage/iris
what are signs of corneal perforation?
these are signs of what condition?
superficial
failure of adhesion of epithelium to enderlying stroma
rarely infected
middle age-old animals
SCCED
spontaneous chronic corneal epithelial defect
what are some forms of tx for SCCED?
cotton bud debridement [50% success]
keratotomy [w/ needle, 80% success]
diamond burr debridement [80% success]
superficial keratectomy
how is cotton bud debridement performed?
remove ALL loose epithelium with cotton bud. be bold!
how is a grid keratotomy performed?
superficial grid made on corneal surface with a needle. NOT on cats
