Ophthalmology - basic steps of examination Flashcards
What are some signs of abnormal ocular conformation?
Sclera showing
Discharge
Colour change
3rd eyelid protruding
Cloudy
What produces the aqueous humour?
Ciliary body
What makes up the neural tunic?
Retina
What makes up the vascular tunic?
Choroid plexus
What makes up the fibrous tunic?
Sclera
Where can you find lists of breeds that are affected by inherited eye diseases?
BVA/KC eye scheme
What is the separation between the upper and lower eyelids called?
Palpebral fissure
Where is the anterior chamber located?
Between the cornea and the lens
Where is the posterior chamber located?
Between the iris and the ciliary body
What suspend the lens?
Zonules/suspensory ligaments
Ciliary bodies
What is parallax and what is it used for?
When the thing that is furthest away will move in the same direction as you
The thing that is closer will move further out the way - move more
Tell whereabouts structures are located in the eye
What is the name of the test which tests for tear production?
Schirmer tear test
What is the normal schirmer tear test for dogs?
15-25mm in 1 min
What are some tests used in a neurophthalmic exam?
Menace response
Visual tracking
Visual placing
Maze test - moving in a new environment
What are some neurophthalmic reflexes?
Palpebral reflex
Corneal reflex
Pupillary light reflex
Dazzle reflex
Oculo-cephalic reflex - globe movement with skull
What can be seen on close direct exam?
Anterior segment
Eyelids
cornea
Iris
Pupil
Front of lens
What dioptre power should you use for converging lenses in an ophthalmoscope?
+10/+15/+20 dioptre power
Increased power = increased magnification
But shorter focal distance - need to get closer
How can you sample from the conjunctiva or cornea?
Sterile cotton bud
Cytobrush
What should you do before sampling from the conjunctiva or cornea?
Apply local anaesthetic
Do not put diagnostic drops in before sampling
What is the normal intraocular pressure of a dogs eye?
10-25 mmHg
What can you use to dilate the pupil?
Mydriatic - 1% tropicamide
What is the onset and duration of action of 1% tropicamide?
Onset- 10-20 mins
Duration - 6-8 hours
Why do you use a mydriatic/pupil dilator?
Enables much better view of the fundus
How do you do an posterior segment examination (fundus)?
Close direct ophthalmoscopy using ophthalmoscope
Indirect ophthalmoscopy
What setting should the ophthalmoscope be on to carry out close direct ophthalmoscopy?
Setting 0
What do you need to carry out indirect ophthalmoscopy?
20D/30D Condensing lens - gives a bigger field of view
A light source
What does the image look like through a condensing lens?
Inverted and reversed
