Eye Flashcards
systemic diseases that can cause ocular signs
Equine protozoal myeloencephalitis
Equine leucoenceophalomalcia
Equine motor neuron disease
Equine encephalomyelitis
thiamine deficiency
vestibular disease
horners syndrome
tetanus botulism
photic head shaking
OU meaning
occurs in both eyes
OS meaning
ocular sinister
OD meaning
ocular dexter
blepharospasm definition
painful closure of eyelid
enophthalmos defintion
globe retracted in orbit
exophthalmos definition
globe bulging out
what to check in examination of head, adnexa
symmetry
scar
pain
globe size
movement
position
eyelids
conjunctiva
eyelashes
lacrimation, discharge
blepharospasm
enophthalmos
exophthalmos
nictitans definition
3rd eyelid
examination of the eye globe
OU same size
shape
symmetry
tense
painless
normal optic axis
tests to check in initial exam
pupillary light reflex
schirmer tear test
collection of specimens
evaluation of vision
intraocular pressure
normal intraocular pressure value
17-28mmHg
normal difference btw the 2 eyes pressure
5mmHg
what reduces intraocular pressure
xylazine
what does normal intraocular pressure reading depend on
time of day
head position
what affects the intraocular pressure
blephrospasm
auricopalpebral nerve block
fibrin
oedema
anisocoria definition
uneven pupil size
dyscoria definition
irregular pupil size
polycoria definition
more than 1 pupil in the eye
how to check direct pupillary light reflex
shine light into eye
check pupil constriction
how to check indirect/ consensual pupillary light reflex
if pupil of affected eye is not visible
direct light into sick eye
check other eye for pupil constriction
where does afferent PLR start
at retina –> optic nerve –> chiasma –> optic tract –> lateral geniculatis nucl –> visual cortex –> n. oculomotor
what is the efferent PLR
pupil constriction
what cranial nerves are used for vision
N. opticus
N. Oculomotorious
N. trochlear
N. trigeminal
N. abducent
N. facial
N. vestibulocochlear
test for N. opticus
vision
PLR
dazzle reflex
menace response
test for N. oculomotorius
efferent PLR
oblique muscles
lateral strabism
ptosis
mydriasis
test for N. trochlear
dorsal oblique muscles
test for N. trigeminal - opthalmic
eyelid movement
cornea reflex
test for N. abducent
lateral retractor muscle
test for N. facial
afferent way
dazzle
menace
ptosis
eyelid reflex
test for N. vestibulocochlear
nystagmus
head tilt
ataxia
what is dazzle reflex
when patient twinkles or blinks when light is directed in eye.
indicates retina function
how many neurons are required for perfect vision
4
neurons required for visula pathway
- rods & cones in retina
- bipolar cell
- ganglion cell
- neurons in corpus genculatum laterale
topical anaesthesia for eye
tetracaine
oxibuprocaine
proparacaine
what to check in anterior section of eye
palpebrae fissure
eyelids
third eyelid
conjunctiva
lacrimal system
sclera
cornea, limbus
anterior chamber
iris & pupil
how to check palpebrae fissure
by inspection
ability to open eye
normal palpebrae fissure
both eyes should be mid wide
symmetrical
no discharge
small dried up mucus at medial canthus
how to examine eyelids
by inspection and palpation
normal eyelids
thin skin gently folded
fit into globe
movement not hampered
regular margin
gently caved
tarsal gland openings seen on lid margin
slightly curved ciliae of upper lid directed outward
how to examine 3rd eyelid
inspection
palpation
normal 3rd eyelid
OU fit into globe at medial canthus
pigmented free margin
palpebral surface is - pale, pink, smooth, shiny, gently vacularised, few lymphoid follicles
normal conjunctive
pale pink
gently folded
covered by tear
moistly shining
vessels not seen
ventral fornix more hyperaemic than superior
limited pigmentation in lateral bulbar surface
how to check lacrimal system
inspection
normal lacrimal system
upper and lower puntas 1-3mm from medial canthus
border can be pigmented
sclera examination
by inspection elevate superior eyelid
normal sclera
covered by conjunctiva
smooth
whitish
without gap/scar
what is the limbus
the border between the sclera and cornea
how is limbus nourished
by diffusion
no blood vessels
normal limbus
corneal surface uniformly glistening
reflected images are bright and sharp
regular in centre
cornea spherical
transparent
blinking reflex
what is the ligament at edge of cornea
pectinate lig
normal anterior chamber
aqueous humour is clear and transparent
corneal precipitate
if aqueous humour is turbid could indicate
high protein content or aqueous flare
if wbc present in aqueous humour
spots on cornea
if fibrin present in anterior chamber
anterior uveitis
if blood present in anterior chamber
hyphema
hypopion definition
when puss and WBC visible in anterior chamber
normal iris
brown or gey
gentle circular pattern of surface
mid wide
centrally place
pupil in eq, ru, su
horizontal elliptical
pupil in ca
round
pupil in fe
perendicular rhomboid
normal lens
bright
clear
regular
no opacity
1st purkinje fibre
on cornea
2 other purkinje fibre
anterior and posterior
last purkinje fibres
upside down
vitreous body
complete transparent gel btw lens and fundus
if you can see retina and fundus clearly, you can say the vitreous body is without opacity
whats in the posterior globe
vitreous body and fundus
diagnostic imaging of eye
vital staining
lacrimal potency
US
retinoscopy
xray, ct, mri
elctrography
oct - optical coverance tomography
fluorescein
confirm cornel ulcer
intact membrane = no stain uptake
rose bengal stain
when pre corneal tear firm mucin layer is thinner than normal
degenerated epithelial cells present on corneal surface
KCS
function of cornea
refraction
protection
layers of cornea
outer - epithelium
middle - stroma
thick basement membrane
bottom - aqueous humor and endothelium
corneal transparency is due to
no blood or lymph vessels in cornea
no keratin in cornea
no pigment in cornea
tear film
microanatomy of stroma
diseases of cornea
ulceration
melting ulcer
corneal ulceration
types
simple or complicated
corneal ulceration
simple
spf abbreviation and loss of epithelial cells
can heal with treatment
e.g. dex, hyaluronic acid, dexpanthexol
only give steroids if epithelium is intact
corneal ulceration
complicated
high risk of corneal perforation
bacteria travel to injury
cause inflammatory cells, leukocytes, elastase, collagenase, proteinase
sofetning stroma –> melting ulcer
what is keratomalatia
if entire cornea is involved AKA melting ulcer
if neutrophils are present
infectious keratinitis
if lymphocytes/ eosinophils are present
immune mediated keratitis
if -ve fluorescin & smooth epithelium
stroma abscess or immune mediated keratitis
if rough ocular surface
SCC
melting ulcer
collagenase enzyme activity digesting stroma
melting ulcer
cause
pseudomonas
b hemolytic streoptococcus
fusarium
aspergillus
melting ulcer
clinical signs
pain, oedema, ulcer, secondary uveitis with myosis and aqueous flare
melting ulcer
diagnosis
slit lamp
cytology - neutrophils, IC and EC bacteria
fungal keratitis
deep groove around lesion
extra plaque on surface
cant give eyedrops
treatment of complicated ulcers
tobramycin
gentamycin
chloramphenicol
natamycin
fluconazol
collagenase inhibitor
atropine
flunixin
or debridement
immune mediated keratitis
IMML
treatment
steroids
cyclosporines
tacrolimus
eosinophilic keratoconjunctivits
proliferation or extra tissue
treat with debridement and steroids