Ophthalmic Exam Flashcards
What are westies predisposed to?
Dry eye - keratoconjunctivitis sicca
What are terriers predisposed to?
Lens luxation
What is hyphaema?
Blood in anterior chamber
What would you suspect of a puppy with hyphaema?
Congenital anomaly
What wold you suspect with a 12 yo dog with hyphaema?
Intraocular neoplasm
What would you suspect with 12 yo cat with hyphaema?
Systemic hypertension
What history should we find out about the ophthalmic history?
- When did the problem start?
- Sudden or gradual in onset?
- Is it progressive?
- One eye or both eyes?
- Pain?
–Closing eye (blepharospasm) ‘winking and blinking’?
–Rubbing eye(s) with paw or on carpet?
•Vision?
–Any difference in day vs night?
–What is vision like in unfamiliar surroundings?
•Change in appearance of eye?
–E.g. redness, discharge…
How do you start an ophthalmic exam?
From a distance
What can we do as part of the hands off ophthalmic exam? (7)
- Symmetry of face
- Symmetry between eyes
- Ocular discharge
- Eye(s) open or closed
- Size of palpebral fissure
- Position of third eyelid
What can be seen?
Different iris colour
What can be seen here?
Left sided facial nerve paralysis and vestibular syndrome
Left head tilt, drooping of left lip
What is this?
Globe rupture secondary to an intraocular melanoma,
copious black discharge
What is this?
Cat with Horner’s syndrome
What can you do as part of the hands on eye exam? (5)
- External anatomy
- Palpation
- Look under upper eyelid
- Examine anterior surface of third eyelid
- Retropulsion
Label
- Upper eyelid with lashes
- Third eyelid
- Medial canthus
- Iris
- Lower eyelid, no lashes
- Limbus
- Sclera
- Conjunctiva
- Lateral canthus
What can be seen?
Describe the use
Purkinje image or corneal ‘reflex’
Provides information on tear film and surface contour
Two white areas – rfeflection of light on the surface. E.g. lights in room, torch or camera.
Surface health of the eye!!
What is this?
Purkinje image
What is this?
Corpora nigra (granula iridca)
What does this show?
Anterior third eyelid
What can be seen?
Palpation (orbital rim)
What are the basic eye reflexes? (5)
- Palpebral reflex
- Menace response
- Dazzle reflex
- Pupillary light reflexes
- Vestibulo-ocular reflex
Palpebral reflex:
A) What is the afferent pathway?
B) What is the efferent pathway?
C) What is the stimulus?
D) What is the normal response?
A) Trigeminal nerve (CN V)
Ophthalmic branch for medial canthus
Maxillary branch for lateral canthus
B) VII
C) Touch gently the medial canthus and lateral canthus
D) Blink (VII)
Menace response:
A) What is the afferent path?
B) What is efferent path?
C) What is the stimulus?
D) What is the normal response?
A) II
B) VII and involves cerebellum
C) Quick, threatening gesture to each eye in turn
D) Stimulated eye should blink
When is the menance response present:
A) In Puppy/kitten?
B) Foals?
A) 12 weeks
B) 1-2 days
Which animal is a menance response being abnormal normal?
Rabbits
Dazzle reflex:
A) What is the reflex?
B) What does it assess?
C) What is the afferent path?
D) What is the efferent path?
A) Subcortical relfex
B) Eye’s ability to detect light
C) Retina, II, rostral colliculus, subcortical connections
D) VII
Dazzle relfex:
A) What is the stimulus?
B) What is the normal response?
A) Very bright focal light shone into one eye
B) Both eyes blink and possible head withdrawal
PLR:
A) What is the afferent path?
B) What is the efferent path?
C) What is the stimulus?
D) What is the normal response?
A) II
B) PNS fibres in III to pupillary constrictor muscle
C) Light shone in one eye
D) Pupil constricts
–Pupil on same side as light constricts
DIRECT PLR
–Contralateral pupil constricts
INDIRECT or CONSENSUAL PLR
•NB indirect PLR is less obvious than direct PLR
Name 2 reasons for a false negative result of PLR (3)
–Weak light source in daylight
•Not strong enough to elicit PLR
–Animal scared/stressed
•High level of SNS tone
–Iris atrophy
•Age-related atrophy of iris musculature
What is the issue of a Positive PLR?
Not always consistent with vision
What does adrenaline do to the pupil?
Dilate
What is this?
Atrophy of iris tissue results in ‘lace-like’
Appearance, large resting pupil size and
or absent PLR
Schirmer tear test (STT):
A) What measurement is this for?
B) What does it measure?
A) Quantitative measurement of tear production
B)Measures aqueous part of tear film (3 parts to the tear film)
Measures basal and reflex tear production
Where do you put the STT and why?
Correct positioning
Lateral third
Too medial- wont get reflex as third eyelid in the way
STT values (dogs):
A) What is normal?
B) What is diagnostic of dry eye?
C) What is diagnostic if clinical signs are present?
D) What is an over production?
A) 15-22mm/min
B) <10
C) 10-15
D) >25
Cat STT:
A) What should each eye be?
B) What is the textbook answer?
C) What is common?
A) same
B) 17mm/min
C) 5-10
Distant direct ophthalmoscopy:
A) what do you set the scope to?
B) How does it work?
C) What is it used for?
A) 0
B) Uses light reflected from tapetal fundus to highlight visual axis
C) Assesses pupil size and clarity of visual axis
What is the method for a distant direct ophthalmoscope?
- Stand at arm’s length from patient
- Set o’scope on 0 dioptres
- Look upwards to pick up tapetal reflex
How do you visualise the tapetal fundus?
Look dorsally
What is the normal tapetal reflection?
Most common colours are green, yellow, blue but red can be normal
Discuss
L – repeat bleeds into eye over months and have glaucoma and the eye pressure is high. No tapetal reflex and old haemorrhage in the eye.
R – not quite normal. Pupil dilated. Yellow/green which is good. Clear. Vitrious is probs okay. Opacity in anterior chamber – blood clot
How do you do a close direct ophthalmoscope?
Close to the animal
What is this?
Monocular indirect ophthalmoscopy
What is this?
Binocular indirect ophthalmoscopy
What tools are used in Indirect ophthalmoscopy?
•Focal light source
–Pen torch
–Finhoff transilluminator
•Condensing lens
–20 Diopter
–2.2 Panretinal lens
Fluorescein dye:
A) What is it?
B) How does it work?
C) When is it used?
A) Orange dye that turns green in alkaline conditions
B) Stains corneal stroma green
C) Very commonly used to diagnose corneal ulcers
What does this show?
Negative fluorescein staining
Doesn’t stick to the cornea
No ulcer
What does this show?
Positive fluorescein staining
Large ulcer – no epithelium and it adheres
What is thenormal IOP in:
A) Dogs and cats?
B) Horse?
C) Rabbit?
A) 15-25 mmHg in the dog and cat
B) 17-28 mmHg in the horse
C) 15-20 mmHg
What is the difference in IOP in two eyes which is considered abnormal?
>10mmHg
What are the 4 mehods of tonometry?
–Digital tonometry
–Indentation tonometry (SCHIOTZ TONOMETER)
–Rebound tonometry (TONOVET®)
–Applanation tonometry (TONOPEN®)
What is ued prior to using Indentation tonometry?
Local anaesthetic
What does Indentation tonometry measure?
Measures degree of indentation of metal rod on cornea
What is a major benefit of using an Applanation tonometry?
Can be used at any angle
How does Applanation tonometry work?
Small footplate, covered by disposable latex tip,
flattens (‘applanates’ hence name) a given surface
area of cornea
Works on the principle of pressure = force/area
What is the difference about using a rebound tonometry rather than applanation and indentation tonometry?
Local anaesthetic drops are not required
How does rebound tonometry work?
Instrument measures deceleration of probe
as it rebounds (hence name) from cornea.
Metal probe has small spherical plastic tip so
area of contact with cornea is very small;
probe is disposable
Interchangable pin
Blob on end – touch cornea and bounce off
Measure the deceleration
What is this?
Indentation tonometry
What is this?
Applanation tonometry
What is this?
Applanation tonometry
What is this?
Rebound tonometry
What is this?
Rebound tonometry
Name 3 tests for vision (4)
•Obstacle course
–Consulting room furniture
- Lights on (photopic conditions)
- Lights off (scotopic conditions)
- Stairs
- Unfamiliar surroundings
- Tracking reflex
Tracking reflex:
A) What is the afferent path?
B) What is the efferent path?
C) How is it done?
A) II
B) III, IV, VI, VIII
C) Get the animal to follow cotton wool
Visual placing response:
A) What is done?
B) What is the normal response?
A) Suport thorax, bring towards table top
B) Place both forepaws on table before carpi touch surface
Corneal reflex:
A) What is it used for?
B) What is the afferent path?
C) What is the efferent path?
D) What is the stimulus?
E) What is the normal response?
A) Assess corneal sensation
B) V opthalmic branch
C) VI and VII
D) Wisp of cotton wool or cotton bud gently touched to cornea, outside of line of vision
E) Normal response: globe retracted (VI) and blink (VII)
What is the Jone’s test?
- Assessment of patency of tear duct
- Passage of fluorescein dye to nostril
- Apply fluorescein to both eyes as normal
- Observe for a few minutes….
Give 3 reasons as to why there may be a false negative with the Jone’s test?
–Dog licks nose
–Accessory openings in mouth
- Open mouth to look for green dye on tongue
- Especially in brachycephalic breeds
–Insufficient dye applied
–Head too elevated
–Insufficient time
How is a seidal test done?
- Fluorescein dye applied to eye, not flushed
- Aqueous humour leakage detected by clear fluid ‘pushing’ fluorescein away from site of concern
Give 2 uses of seidal test (3)
–Following removal of a corneal FB
–Corneal laceration e.g. cat scratch
–Suspicion of perforated corneal ulcer
Discuss this seidal test
Leaking – black area is aqueous humour pushing away Good for a cat scratch injury
Name 3 infections we may use a swab for in a cat. Which are the two most important?
–Chlamydophila felis
–Feline herpesvirus-1 infection
–Mycoplasma felis
–Feline calicivirus
- Bordetella bronchiseptica
How do you take a conjunctival swab?
Apply local anaesthetic eye drops
Retropulse globe through upper lid to protrude TEL
Roll swab several times in front of TEL
Where do you swab for:
A) Conjunctivitis?
B) Corneal ulcer?
A) Conjunctival sac
B) Cornea
Why do cats need GA for Nasolacrimal flush?
Very small punctal opening
How would you do a Nasolacrimal flush?
- Cannulate upper punctum
- Attach 2ml syringe of saline/water
- Flush gently, look for fluid at lower punctum
- Occlude lower punctum
- Continue flushing, head down slightly
- Look for fluid a ipsilateral nostril
Which species only have 1 punctum?
Rabbit - lower
What is a common problem with rabbit tear ducts?
Dacryocystitis (inflammation +/- infection of tear duct)
Vestibulo-ocular reflex:
A) What is the stimulus?
B) What is the normal response?
A) Change in had position
B) Both eyes move together
What is Vestibulo-ocular reflex independant of?
Vision
How do you do a Vestibulo-ocular reflex in cattle and why?
- Cattle roll eyes downwards dramatically when you try to examine them
- Roll head down, not up, to make the eye turn upwards
Gonioscopy:
A) What is it an assessment of?
B) What do you look for?
A) Iridocorneal drainage angle
B) Predisoposition of glaucoma
What is slit lamp biomicroscopy used for?
- Excellent illumination and magnification of eye surface
- Slit beam of lights helps to e.g. judge depth and localise lesions
What is this?
Using a Slit-lamp biomicroscopy
Deep corneal ulcer
A) What is an Electroretinography used for?
B) How does it work?
A) Assessment of retinal function
B)
- Corneal electrode = contact lens
- Skin electrodes, light source
- Electrode on eye and under skin – connect to PC
