Ophtalmic examination Flashcards
What is the general structure of an ophtalmic exam?
look at both globe and adnexa
in a specific order: outside to inside or eyelids to retina
examine both eyes: comparison, bilateral/symmetry, systemic diseases
What are important questions to ask during hx of an ophtalmic exam?
signalment: breed, age, use/work, etc.
reason for consultation: change in appearance, change in behaviours, loss of vision, ocular pain
duration of signs, ocular discharge, redness, discomfort, rubbing, affect vision
systemic signs/disease
What do we look at during the hands off ocular exam?
behaviour - vision
size and position of globes
asymmetry of eyes and face
signs of discomfort (blink rate, tears, rubbing, etc.)
abnormal eyelid or 3rd eyelid conformation
ocular discharge
What are the main things to look at during hand on general ocular exam?
palpation and gentle retropulsion of globes
closer exam of adnexa
external exam of globe: conjunctive, episclera, cornea
palpebral reflex
menace response
vestibulo-ocular reflex
What is the schirmer tear test 1 how do we perform it?
semiquantitative method of measuring aqueous portion of precorneal tear film
fold strip while packed, insert tip in lower conjunctival fornix
1 minute per eye
What values are normal vs abnormal with an STT?
in dogs 15 and above = normal reading
10 and under = low reading
if unclear repeat at a later time
- dog in pain will tear more
What is a focal light examination?
multiple tests: dazzle reflex, PLR, swinging light test, retroilumination
What is the dazzle reflex?
partial blink reflex in response to light
What is the PLR?
pupillary light reflex
both pupils should constrict when light is in 1 of them (non lighted less than lighted)
What is the swinging light test?
in dim light swinging light from 1 pupil to another
consensual light reflex
What is retroilumination?
shining light to see the tapetal reflection
looks at pupillary size, shape and symmetry, presence and opacity within the visual axis
What is the palpebral reflex?
touch corners of the eyes for them to blink
What is the menace response?
moving hand slowly towards the eye, should blink
What is the vestibulo-ocular reflex?
head rotation causing opposite eye movement
What is dyscoria?
when the pupil shape is abnormal for that species
What is synechia?
When there is adhesion between tissues in the eyes where there shouldnt be
What is anisocoria?
coria = pupil
asummetry in the pupil size
What is mydriasis?
anisocoria where there is one large pupil
What is miosis?
anisocoria where there is one small pupil
How do we know if there is one larger pupil?
turn lights off
retroiluminate
if the pupil is already big, it can’t get bigger
but the normal pupil will dilate = the sizes of pupils will be more similar in the dark
How do we know if there is one smaller pupil?
turn off lights
retroiluminate
normal/bigger pupil will increase in size
small pupil can’t change much
difference in sizes between the pupils will become much bigger
How does retroilumination allow to test for an opacity within the visual axis?
any opacity will obstruct the passage of light towards the tapetum lucidum and will obscure the tapetal reflex
helps us locate the opacity
differentiates between cataracts and nuclear sclerosis
What is hypaema?
blood within the anterior chamber
will block the light going towards the tapetum
How can we tell if the opacity is in the anterior or posterior chamber of the eye?
When moving an opacity in the anterior chamber will move away from us
an opacity in the posterior chamber will move towards us
and opacity in thee middle will not move
What is nuclear sclerosis?
normal aging change, isn’t blinding
lens nucleus becomes compacted with time causing a refractive change within the lens, a blue/gray appearance
What is a cataract?
any true opacity within the lens
potentially blinding
What should we examine on the eyelids?
hairless eyelid margin
different degrees of pigmentation
meibomian gland openings
What do we examine on the ocular surface?
variable pigmentation but minimal vascularisation visible
purkinje reflexes
What is the purkinje reflex?
reflecting light source on the eye’s surface and looking for a sharp and smooth reflection vs a dull and disrupted one
How do we describe the location of corneal and iris lesions?
using a clock
dorsal/lateral/medial/ventral
cornea: periphery/paraxial/axial
iris: periphery/peripuilary/pupil
What is hypopion?
pus in the anterior chamber
What is keratic precipitates?
WBC in anterior chamber
What is the tyndall effect?
looking if there is continuation of a light beam within the anterior chamber, indicating there is more than just water
What condition can the tyndal effect help confirm?
uveitis
What is tonometry?
estimation of the intraocular pressure (IOP)
high: glaucoma
low: uveitis
What is the normal range of IOP for SA?
10-25 mmHg
high variability between individuals, technique used, time of day
difference should be less than 20% between both eyes
What are topicamide eye drops?
dilate the pupil
What is direct ophtalmoscopy?
provides direct upright image of the fundus
19.5x magnification, limited field of view
has both positive and negative dioptre lenses
distant: retroilumination/pupil
close: retina
What is indirect ophtalmoscopy?
virtual inverted slightly magnified image
pupils need to be dilated
monocular: no depth perception
binocular: depth perception
What is the sclera?
most posterior layer of the eye
collagen and some blood vessels
What is the choroid?
marked pigmentation layer, large blood vessels
What is the tapetum?
very shiny surface of the choroid
colour and size depends on the animal/eye
What is the RPE retinal pigmented epithelium?
monolayer cells between choroid and retina
heavy pigmented cells
What is the retina?
most inner layer containing retinal vasculature
continuous with the optic nerve
thick but transparent
What is a fluorescein stain?
to test for corneal ulcers
rinse of with saline, examine surface with blue light
What is a jones test?
fluorescein stain not rinsed
monitor flow to the nose after 4+ min
blue light
reaches nose: no blockage
doesn’t reach nose: blocked, indication for flushing
What is the seidel test?
fluorescein test to determine if there is perforation of the eye
use cobalt blue light
monitor for aqueous humour leaks
When is a corneal/conjunctival cytology indicated for?
purulent conjunctivitis
inflammatory infiltrate cornea
melting ulcer
careful in case of a fragile eye
