Ophthalmology Flashcards
Mydriasis
dilated pupil
Cause of an eye to turn yellow
combination of protein and probably white blood cells in the aqueous humour.
Tear reading test?
Schrimer Tear Test: 15mm/min & above are normal
10mm/min & less are low readings
uses of Slit examination
Anterior structures of the eye − Detail - Eyelids, conjunctiva and third eyelid (non-transilluminable) − Cornea, iris and anterior lens (transilluminable) • Contour • Lesion depth (ulcer, cataract) • Reflexes − Dazzle reflexes − Pupillary light reflexes
causes of Keratic precipitates?
uveitis
can you have a PLR with cataracts
yes, not a vision test, so light can still causes a PLR
Nuclear sclerosis Vs. cataracts
Nuclear sclerosis is transparent, Cataracts appear black on DDO
Jones Test
nasolacrimal duct patency
Distichiasis
hairs exiting from the duct of the meibomian gland at the eyelid margin: causes corneal ulcers, tearing and inflammation
hair sporuting from the conjunctiva of the bulbar surface, central upper eyelid of a young dog
Ectopic cilium
Hairs from a “normal location” contact the ocular surface
Trichiasis
Conjunctiva congestion
Have dichotomous branching
episclera congestion
Episcleral BVs have no dichotomous branching
– Larger
– Meander
What does episclera congestion signal
Intraocular disease (uveitis and glaucoma) » Severe/chronic surface irritation
Damage to the corneal endothelium can cause
Glaucoma, uveitis, lens luxation and primary endothelial deneration
loss of epithelium causes
corneal ulcer
where is aqueous humor produced and exit
ciliary body and exits at the ICA/sclera/ uvea
2 diseases effecting AC (how to differinciate)
uveitis (decreased IOP) and glaucoma (increased IOP)
What is the UVEA made up of
anterior uvea: iris and ciliary body
Posterior uvea: choroid
signs of uveitis
keratic precipitates, miosis, hypopion, hyphema, and posterior synechiae
abnormal pupil shape
posterior synechiae ( iris attached to lense): uveitis
Differentials for working up a red eye case?
DAMNIT (degeneration,developmental, autoimmue, acquired, metabolic, neoplastic, nutritional, neurological, infectious, inflammortory, immune mediated, Trauma, toxic
epiphora
overproduction of tears: trigeminal nerve irritation/inflammation or draining
components of tears and sites of production
aqueous (lacrimal + accessory glands), lipid(meibomian glands) and mucus (goblet cells)
entropion
inward pointing of eyelashes
link with entropion and corneal irritation
corneal irritation causes Blepharospasm causing spastic entropion therefor more corneal irritation.
causes of blindness
symblepharon, uveitis, glaucoma, cataracts, keratitis, PPM, PRA
Symblepharon
adhesion of nictitans membrane or cornea to conjunctiva of eyelid (causes blindness)
brachycephalic dog with euryblepharon, entropion and pigmentation of the sclera and cornea
pigmentary keratitis (causes blindness)
lines across the pupil
persistent pupillary membranes (causes blindness)
Flare
presence of inflammatory particles in the AC giving it a cloudy appearance (tyndall effect) : Uveitis
synechia
attachment of iris to lens (posterior) or cornea (anterior)
when is topical anti-inflammatory treatment for uveitis counter indicated
with a corneal ulcer
systemic hypertension can cause
Bullous retinal detachment hyphema, retinal haemorrhage.
cataracts
Complete or focal opacity of the lens, can be secondary to or cause uveitis: white on DDO and dark with retinalillumination
causes of cataracts
inherited, traumatic, metabolic (diabetes), congenital, nutritional, PRA and senile
nuclear and cortex cataracts
Nuclear: center commonly inherited
Cortex: around edge, senile cause
middle aged labrador with night blindness leading to day blindness, painless, cataracts
Progressive retinal atrophy: Loss of blood vessels on retina
difference between cataracts and nuclear sclerosis
Cataracts: dark on retinoillumination, y shaped
Nuclear sclerosis: Bilateral white pearl(marble in eye)
how do you retinalilluminate the lens
bend yours knees and shine light up to top of eye and use the tapitum reflection to illuminate the lens.
cataracts shows up as dark nuclear sclerosis does not
cause of exophthalmos and 3rd eyelid protrusion
space occupying lesion
buphthalamia
enlarged eye due to increase IOP
burmese cat with dilated pupil, conjunctival and episcleral congestion, vision problems
glaucoma
If schirmir test less than 15 milliliters of tears produced in a minute
Keratoconjunctivitis sicca
dry eye
Clinical signs of dry eye?
corenal ulceration, conjunctival congestion, red eye and yellow or green discharge
typical breeds disposed to keratoconjunctivitis sicca
cocker spaniel, cavailer, bulldogs ect
treatment options for KCS
surgery: conjunctival pedicle
Medical:topical ciclosporin (immunosuppressant), tear replacement and topical antibiotics (chlormanphenicol)
black dot in the centre of cornea of a cat
feline corneal sequestrum
treatment: surgery
cause of symblepharon in kitten and corneal ulcers
FHV-1
Marcus Gunn sign?
reduced constriction of one eye on the swinging light test: lesion in the optic nerve before optic chiasm (on opposite side!) or severe retinal disease.
result of lesion effecting the left optic tract
loss of sight in the right eye
differentiation between PPM and posterior synechiae
PPM always effects from edge of pupil to the centre but posterior synechiae only ever effects the edge never the centre
