Ophthalmology Flashcards
what are the main signs of eye pain?
blepharospasm
reduced palpebral fissure
ocular discharge/epiphora
hyperaemia
what is blepharospasm?
increased blink rate
what is epiphora?
watery eyes
what is hyperaemia?
redness
what are the local signs of occular pain?
photophobia
miosis
third eyelid protrusion
head shy
self trauma
what is miosis?
constricted pupil
what are the systemic signs of occular pain?
reduced appetite
quiet
subdued
depressed
lethargic
headache
how should occular cases be triaged?
systemic signs
brief outline of occular signs
speed of onset
duration
when should patients with occular pain/issues be seen in practice?
same day wherever possible
what is the downside of using standard pain scoring to assess occular pain?
it is influenced by blepharospasm
what are the 3 sections of the ophthalmic patient pain score?
overall demenour
observation of blepharospasm
rubbing of the eye
what score on the ophthalmic patient pain score suggests analgesia is required?
> 3
what are the main methods of management of ophthalmic pain?
medical - topical and systemic
surgical
who must advocate for the patient?
veterinary team
what must be treated?
cause of the pain
what may be causing an animal occular pain?
scratchy dry lids
acute ulcer
uveitis
chronic glaucoma
orbital swelling
unknown - unable to open eye to see
how may dry eyelids be treated?
lubrication with HA drops
how may pain from acute ulcers be treated?
bandage contact lens
how do bandage contact lenses prevent pain?
covers nerve endings
how may pain from uveitis be treated?
atropine or Cyclopentolate drops to relax muscle
how may pain from chronic glaucoma be treated?
enucleation
how may pain from orbital swelling be treated?
NSAIDs
opioids
how may an eye that cannot be opened be treated?
LA
sedation
GA
how should blind or partially sighted patients be handled?
go slowly
hand on chest initially
talk to them
guide then whilst walking
avoid bumping into things
why is avoiding bumping into things essential if the eye is fragile?
could lead to rupture
how should patients be handled for occular exam?
assessment of temperament - is muzzle needed
keep steady
keep calm
placed at the table edge
reward and reassure
what are some of the main causes of vision loss?
cataract
glaucoma
SARDS
toxins
PRA
brain disease or trauma
what are the 2 main reasons that cateracts develop?
inherited
diabetic
how is glaucoma caused?
inherited genetic defect
secondary to intraocular neoplasia, uveitis or lens luxation
how is glaucoma treated?
medically managed initially
surgical shunt implant
laser TSCP/ECP
ultimately enucleation
what is SARDS?
sudden acquired retinal degeneration syndrome
how is SARDS confirmed?
flat line on electroretinogram
how is SARDS treated?
no treatment
what toxins can cause blindness?
ivermectin poisoning
enrofloxacin in cats
what is PRA?
progressive retinal atrophy
what breeds is PRA common in?
cocker spaniels
what type of vision is lost first with PRA?
night and then day
how can PRA be diagnosed?
simple maze test with lights on and off
ERG can show if rods not responding and so night vision lost
how important is sight to animals?
scent and hearing most important
adjust very well to blindness
how can owners support their blind pets at home?
online forums for blind pet owners
RSPCA
buster collars
guide leads
doggles
voice commands for stairs etc
behaviour training
lead walks offer more support
will eye ulcers heal if we do nothing?
if simple will heal in 7 days with no intervention
what must be done if ulcers are lasting more than 7 days?
investigation of underlying issue
what is the issue with not treating ulcers?
pain
infection risk
delayed healing
risk of keratomalacia
how does keretomalacia occur?
enzymes in tears break down cornea which can lead to globe perforation
what may happen if ulcers are not correctly managed?
perforation
endophthalmitis
glaucoma
phthisis
blindness
what typeof epithelium is the cornea formed from?
transparent stratified squamous epithelium
what is an integral part of the cornea?
tear film on upper surface
what is the limbus of the eye?
transition zone to sclera
what is the sclera?
fibrous tunic
what is the role of the sclera?
gives globe rigidity
what are the different ulcer depths?
superficial
deep
descemetocoele
perforation
how can ulcers be classified?
depth of stroma affected
size
type
what is the effect on the stroma of a descemetocoele ulcer?
all stroma is lost
when is an eye classed as fragile?
> 50% stromal loss
what layer of the eye can ulcers reach that makes the eye extremely fragile?
Descemet’s layer
what can cause eye rupture if eye is fragile?
any increase in IOP
what may cause increased IOP?
barking
jugular samples
coughing
vomiting
collar
firm restraint
what breeds are commonly affected by severe ulcers?
brachycephalic breeds
how should animals with fragile eyes be treated?
avoid pressure on neck/lids
keep venous pressure low to keep IOP low
avoid stress
caution with occular tests used
ensure meds given regularly
keep eye area clean
what ulcer types are there?
SCCED
stromal ulcers
melting ulcers
descemetocoeles
perforation
what is SCCED?
spontaneous chronic corneal epithelial defect
how can SCCED be treated?
algar brush
grid
superficial keratectomy
what is a superficial keratectomy?
top layer of the cornea removed
how are stromal ulcers / feline sequestrum treated?
medical
surgical graft
how are melting ulcers treated?
intense medical management initially
corneal cross linking if cornea unstable
corneal graft
how are descemetoceles treated?
structural support imperative
corneal-conjunctival transposition
how is eye perforation treated?
suture closed
graft
corneal transplant
how should patients with fragile eyes be managed around anesthesia?
low stress
smooth pre-med (IV) and induction
smooth recovery
consider not reversing premed
where should horses be kept following eye surgery?
dark stables to allow atropine to be used
what is involved in post occular surgery care?
harness only
no jugular samples
buster collar needed
monitor and treat pain
administer meds
keep wounds clean and dry
keep patient calm
what types of trauma are ocular emergancies?
sharp trauma
blunt trauma
proptosis
penetrating FB
what is proptosis?
eyelids trapped behind the globe which pushes the eye out of the orbit
what are the priorities for occular emergencies?
CVS stability
analgesia
occular surface support
eye lubrication
prevent further trauma
stabilise any FB
buster collar to prevent self-trauma
when do puppies develop a menace response?
between 8-12 weeks
what can be caused by cat claw injury to the eye?
corneal laceration
lens puncture
capsular tear
cataract formation
lens induced uveitis
what may be needed to treat cat claw injuries?
cataract surgeries with phaecoemulsification
corneal laceration repair
medical treatment of uveitis
how can risk of cat claw injury be reduced?
ensure owners with cats and puppies are aware of when mencae response develops
what visually about the eye can indicate glaucoma?
blue cornea
red sclera
conjunctiva
what can be caused by glaucoma?
blindness and pain
what can chronic glaucoma cause?
buphthalmic eye
what is a buphthalmic eye?
eyeball is bigger as globe is stretched
does the eyeball move from its position in the orbit if glaucoma is seen?
no - remains in it’s normal position inside the orbit
what is normal IOP?
10-25 mmHg
what IOP can be seen with glaucoma?
> 30 mmHg
what can a IOP of >40mmHg cause?
blindness in 24-28 hours
what can cause exophthalmos?
FB causing retrotubular abscess or cellulitis
elevator slip trauma if recent dental work
stick injuries
what are the signs of retrotubular masses?
pain on opening mouth
exophthalmus
excessive conjunctiva visible - especially third eyelid
what is exophthalmus?
eye is pushed forwards
what is the role of lubricant eye drops?
protect
soothe
support healing
provide nutrients to eye
what is the role of antibiotic eye drops?
treatment
prophylaxis
what types of anti-inflammatory eye drops are available?
NSAIDs
steroids
what is the role of immune modulator eye drops?
treatment of immune mediated disease
what is the role of anti-glaucoma eye drops?
lower IOP
what is the role of mydriatic eye drops?
dilation of the pupil
what mydriatic is commonly used?
atropine