Opthalmology Flashcards
what are the 7 steps in an ophthalmic examination
history
distance examination
tear test and corneoconjuncitva examination
adenexa and anterior segment examination
intraocular pressure measurement and pupil dilation
posterior segment examination after pupil diltion
additional techniques ifndicated
4 types of apetures on an ophthalmoscope
circle - direct illumintion or retro-illumination
slit beam - assess curvature of cornea and depth of anterior chamber
grid - assess location and size of a lesion
half-light - focuses light so can look at unaffected areas of the eye
what types of filters can you use on an ophthalmoscope
white light - direct illumination
red-freee light - differentiate vessels
blue cobalt - elicit ulceration and corneal erosions
what is meant by schedule A under the BVA eye scheme and what breeds does this include
conditions that are confirmed to be inherited - labradors and cocker spaniels
5 things to look for on a distance examination
attitude of the animal
facial symmetry and ocular discharge
eyelids - size, colour etc eyeballs - position and size
pupils response to light
what is meant by a neuro-ophthalmic examination
pbserving the animals movement in their environment through visual testing (menace etc)
what is meant by strabismus
deviation from the usual visual axis
what is anisocoria
different size of pupils
what is mydrisasis and miosis
dilation of pupil and constriction of the pupils
what is a normal reading for a dog with schirmer tear test
greater than 15mm/min
what is the problem with the shcirmer tear test
measures both basal and reflex tear production
how to you assess the quality of the tears
tear break up time - using fluorescine to measure time tears remain on the cornea
how long should the tear break up time be
at least 20 seconds
what lens do you use for a close direct examination
converging - green or black with slit beam aperture
what are the 3 main features to look for at close direct examination
cornea, anterior lens capsule and posterior lens capsule
what is a normal measurement for intraocular pressure
10-25mmHg
when would you test the intraocular pressure
before dilating the pupils
name the 7 eye muscles
lateral rectus superior rectus medial rectus inferior rectus superior oblique inferior oblique retractor bulbi
what is exophalmos
protrusion of the eyeball
what is enophthalmos
recession of the eyeball into the orbit - sunken eyes
whats the main cause of exopthalmos
retrobulbar space occupying lesioncaused by infection, foreign body, trauma or haematogenous infection
how would you treat exopthalmos
drainage, antibiotics and NSAIDs
what is proptosis and what breeds are predisposed
eyelides become entrapped at the back of the globe - cocker spaniels
2 treatment options for globe proptosis
enucleation or transpalpebral approach
what are 4 possible causes of enophthalmos
ocular pain
decreased orbital content - reduced fat due to starvation or dehydration
certain breeds - dolciocephalic
damage to sympathetic nerves - claude bernard horners syndrome
what is meant by macropalpebral fissure
abnormally large opening between the eyelids
what is meant by blepherospasm
tight closure of the eyelids
what is lagopthalmos
incomplete closure of the eyelids so the tear film is not spread scross the entire cornea
what are possible consequences of lagopthalmos
conjunctivitis, keratitis and corneal vascularisation
treatment for lagopthalmos
lubrication and antibacterial drugs
what size is a normal eye considered to be
33-35 cm
what are treatment options for oversized eyes
blepheroplasty and eyelid shortening
what breeds are prone to oversized eyes
bloodhounds, great danes, boxers
what is trichiasis
hairs directed towards the cornea due to skin abnormality
what is distichiasis
cilia emerging from the meibomian gland orifice that CAN come into contact with the cornea
what is ectopic cilia
cilia from the meibomian gland but emerge from the palpebral conjuncitva and are always in contact with the cornea
what type of epithelium is the conjunctiva
keratinised
what is hyperaemia
redness and inflammation due to increased blood supply
what is blepharospasm
tight closure of eyelids in response to pain
what is the correct term for dry eye
keratoconjunctivitis sicca
3 types of primary conjunctivitis in dogs
allergic, follicular and bacterial or parisitic
main differences between un complicated and complicated conjunctivitis
shorter duration with milder symptoms, vision remains, no corneal involvement and responds to medical treatment
treatment for cherry eye
NSAIDs, chloramphenicol or surgical with pocket technique
3 layers of the pre corneal tear film
deep mucin layer, aquoues layer and superficial lipid layer
what glands produce the mucous, aqueous and lipid layers of the tear film
Meibomian glands- lipid, goblet cells - mucous, lacrimal gland - aqueous
what are the main functions of the pre corneal tear film
even distribution of the film, nutrition of the cornea, help renew epithelium and keep eye moist, lubrication of cornea
what nerves supply the lacrimal gland
facial and trigeminal
3 possible causes of dry eye
immune mediate, breed disposition, anaesthetic response, neurogenic or traumTIC
what is normal value for a dog STT
15-25mm
what would the STT be for moderate to severe dry eye
0-10mm
what is dry eye due to
low quality or low quantity of tear production
what causes qualitative dry eye
inflammation of Meibomian glands that produce the lipid layer
what is a STT less than 5 seconds indicative of
abnormal tear quality and of goblet cells
treatment of KCS
lubrication, immunomodulating agent, antibiotics, parotid duct transposition
what is epiphora
overflow of tears due to increase production or decreased drainage
What is the jones test used for and what does it measure
tests permeability of nasolacrimal duct - measuring how much flouroscein is at the level of the nostrils after 5 minutes
what is dacryocystitis
foreign body in the nasolacrimal duct system causing infection
what is the limbus
transition between sclera and cornea
what makes the cornea transparent
no vessels, no pigments, non-keratinised epithelium
what does a blue cornea indicate and how would you treat
oedema
topical hypertonic saline solution
what does a red cornea indicate
corneal neurovasculisation
differenct between superficial and deep vessels of the cornea healing
superficial are bright red and have fine branches
deep - dark and straight indicate deep trauma
what does a white cornea indicate
scarring or metabolic infiltrates
what does black cornea indicate
pigments
what does pink cornea indicate
chronic superficial keratitis - pannus
how long will an epithelial and a stromal ulcer take to heal
2 weeks months to years
how would you treat a superficial corneal ulcer
chloramphenicol and lubrication
most common cause of a deep ulcer
pseudomonas infection
how would you treat a melting ulcer
autoproteolytic drugs
what is a chronic corneal epithelial defect
indolent ulcer - superficial ulcer not healed in 1-2 weeks
how would you diagnose an indolent ulcer
lose ring of epithelium around the ulcer
what makes up the uvea
choroid, iris and ciliary body
differenct between anterior and posterior uveitis
ant = breakdown of blood aqueous barrier and post = breakdown of blood retinal barrier
