Ophthalmic and otoscopic examination Flashcards
Name the device that measures intraocular pressure
Tonometer
What can be used to dilate the pupil?
Mydriatics
What can be used to test tear production?
Schirmer tear test strips
Name the dye used to highlight corneal defects
Fluorescein
Give some example features of all ophthalmoscopes
Beam selectors
Lens magazine
Brightness dial
What is the function of the beam selector on an ophthalmoscope?
Alter the shape of the light beam for different uses
What shapes can the light beam be altered to in an ophthalmoscope, what is each shape used to look at?
- circular: whole pupil
- slit beam: anterior segment
- half moon: Useful if there is an obstruction preventing light travelling to the fundus
- Graticule/grid: useful for location and measurement of lesions
What 3 colours can the light beam be changed to, what is the function of each?
White - used for most of the exam
Cobalt blue - used with fluorescein dye to highlight corneal defects
Red free filter - used to examine vasculature and retinal nerve fibres
What is the lens magazine on an ophthalmoscope?
Alters the lens strength for visualisation of structures at different levels within the eye
The unit of measurement representing the optical power of a lens is known as a…?
Dioptre
Describe the first stage of an opthalmic exam
Observation
- from a distance, in normal light
- behaviour, posture, movement
- Is the patient exhibiting any abnormal signs such as:
Blepharospasm - closure of eyelids (looks like squinting) or excessive blinking
Epiphora – overflow of tears
Photophobia – sensitivity to light
- Is the face symmetrical, and is the position of the globe normal?
Describe the second stage of an opthalmic exam
Hands on, normal light
- Examine the eyelids and bulbar and palpebral conjunctiva.
- You can protrude the nictitating membrane
(3rd eyelid) by gently pulling down the lower lid and applying gentle digital pressure to the globe through the upper lid
- Observe pupil size and symmetry
- Menace response in both eyes
- Asses the corneal light reflex
Describe the third stage of an opthalmic exam
Hands on, lights off
- Using a pen torch alone or with magnification, examine the eye systematically
In the hands on, lights off stage of an ophthalmic exam, which parts of the eye are being assessed?
- Adenexa – examine the lid margins and conjunctiva in detail
- Cornea – is it clear and smooth? Note any lesions
- Anterior chamber – use the torch at various angles to trans illuminate the chamber and look for any abnormal contents
- Iris – check colour, texture, pupil margin and pupil shape
- Lens – a limited examination of the lens is possible using this method, but more detailed examination will require medical dilation of the pupil.
Name the two tests, that take place in the third stage of an ophthalmic exam, that require a more concentrated light beam
- Pupillary light response
- Dazzle response
Describe the fourth stage of an ophthalmic exam
It is worth practicing using both eyes, as ideally you want to be eye to nose with your patient.
Place your free hand under the animals chin and stand at arm’s length from the head.
Set your ophthalmoscope to +1D or +2D and look through the visualiser straight into the pupil to
appreciate the tapetal reflex – the greenish reflection from the tapetum.
In older animals, what is a common finding on distant direct opthalmoscopy, how does it present?
Nuclear sclerosis - shows as a refractile (shiny) ring or circle within the lens
What is the 5th stage of an ophthalmic exam?
- Close direct ophthalmoscopy
- used to examine the fundus, and then the more anterior structures of the eye, in detail
- Position the ophthalmoscope close to the patient’s eye, then place your own eye on the visualiser - the scope should touch your face.
- Locate the optic disc – assess the shape, size, position and colour
- Examine retinal blood vessels
How does the position of the optic disc differ in dogs, cats and horses?
Dog: At tapetal/non-tapetal junction
Cat: In tapetal area
Horse: In non-tapetal area
When begining at otoscope examination what needs to be considered?
- diseased ears can be painful
- be gentle at all times
- ensure food restraint
What are the two distinct regions of the ear canal?
Vertical canal
Horizontal canal
Describe the basic steps of an otoscope exam, including how to examine the vertical and horizontal canals
- Gently lift the pinna and examine the external opening to the ear canal - note any discharge or inflammation
- Gently introduce the speculum of the otoscope into the ear canal
- The first part of the canal is the vertical canal, so at this point your otoscope speculum should be angled downwards
- To visualise the horizontal canal you will need to alter the angle of the speculum, from vertical to horizontal, so that it is around 90o to the patient’s skull.
What ca be visualised at the end of the horizontal canal?
The tympanic membrane
Name the 5 stages of an ophthalmic exam
1: Observation
2: Hands on, normal light
3: Hands on, darkened room
4: Distant direct ophthalmoscopy
5: Close direct ophthalmoscopy
At what age does the menace response develop?
12 weeks of age
