Ophthalmology

Question 1

What are some signs of eye pain?

Answer 1

Blepharospasm (increased blink rate)
Reduced palpebral fissure (blink/wink)
Ocular discharge / epiphora
Hyperaemia (redness)
Photophobia
Miosis (small pupil)
Third eyelid protrusion
Head-shy/self-trauma

Question 2

How should we triage ocular patients?

Answer 2

Systemic signs e.g. reduced appetite, subdued/depressed, lethargic
Brief description of ocular signs
Onset and duration
Be careful - owners cannot always identify pain or severity accurately

Question 3

How can we manage ophthalmic pain?

Answer 3

Medical options - topical and systemic
Surgical options
Treat the cause!

Question 4

How should we handle ophthalmic patients for examination?

Answer 4

Assess temperament
Keep steady and calm
Hold at end of table
Reward and reassure
Nurse restraint!

Question 5

What are some causes of vision loss?

Answer 5

Cataracts - inherited or diabetic
Glaucoma - primary inherited / secondary to intraocular neoplasia, uveitis, lens luxation
SARDS (sudden acquired retinal degeneration syndrome)
Toxins - ivermectin, enrofloxacin
PRA (progressive retinal atrophy)

Question 6

Why do we need to treat ulcers?

Answer 6

Pain
Infection risk
Risk of keratomalacia (melting)
Perforation, endophthalmitis, glaucoma, phthisis, blindness

Question 7

What are the classifications of ulcers?

Answer 7

By depth of stroma affected
Superficial
Deep
Descemetocoele
Perforation

Question 8

What post-op care should we provide for ophthalmic patients?

Answer 8

Harness walks, no jugular samples (raised IOP)
Buster collar to prevent self trauma
Recognise, monitor and treat pain
Administer eye medications
Keep wounds clean and dry
Keep patient calm

Question 9

What traumas are an ocular emergency?

Answer 9

Sharp trauma
Blunt trauma
Proptosis (eyelids trapped behind globe)
Penetrating FBs

Question 10

What are our priorities with ocular emergencies?

Answer 10

Cardiovascular stability - ABC
Analgesia
Ocular surface support - lubrication
Prevent further trauma, stabilise any FBs and use Buster collar
Stabilise, assess, plan, treat

Question 11

Describe a cat claw injury.

Answer 11

Puppies develop menace response at 8-12 weeks, meets defensive cat
Corneal laceration
Lens puncture / capsular tear
Cataract formation
Induction of lens-induced uveitis

Question 12

How can we treat cat claw injuries?

Answer 12

Cataract surgery with phaecoemulsification
Corneal laceration repair
Medical treatment of uveitis

Question 13

Describe uveitis.

Answer 13

Trauma causes inflammation in eye
Blood-ocular barrier breakdown = uveitis
Inflammation damages delicate structures
Systemic disease can cause uveitis
Urgent treatment needed once recognised

Question 14

Describe glaucoma.

Answer 14

Blue cornea, red sclera and conjunctiva
Blindness in 24-48hrs, pain
Chronic = globe stretched/enlarged, remains in normal position within orbit
Can be post-op complications after cataract surgery
High IOP (>30mmHg)

Question 15

What can cause retrobulbar masses and exophthalmos?

Answer 15

FB could go into orbit and cause retrobulbar abscess/cellulitis
Recent dental work - elevator slip trauma
Stick injuries from chewing/running into

Question 16

What are the signs of retrobulbar masses and exophthalmos?

Answer 16

Pain on opening mouth
Exophthalmic eye (pushed forward)
Excessive conjunctiva visible esp. 3rd eyelid

Question 17

What are the different types of eye drops and what are they used for?

Answer 17

Lubricants - protect, soothe, support healing
Antibiotics - treatment/prophylaxis
Anti-inflammatories - NSAIDs/steroids
Immune modulator - immune-mediated disease
Anti-glaucoma drugs - lower pressure
Mydriatics - dilate pupil
Local anaesthetic - diagnose/pre-op

Question 18

How can we make serum eye drops?

Answer 18

From FFP or serum
Patient’s own, donor animal fresh or FFP

Question 19

How long should we leave between drops and gels/ointments?

Answer 19

Leave 10mins between each drop
Leave 60mins between each gel/ointment

Question 20

What order should drops be administered in?

Answer 20

Watery aqueous drops first, wait 10 mins
Suspensions, wait 10 mins
Gels, wait 60 mins
Ointments last

Question 21

What are the benefits of eye lubricants?

Answer 21

Support healing of all ocular surface disease
Nutrition of cornea through tears
Reduce evaporation
Prevent ulceration post-op
Replace missing tears
Comfort!

Question 22

What patient factors should we consider when preparing for ophthalmic surgery?

Answer 22

Physical mobility, systemic health - often young/old patients
Conformation/concurrent BOAS
Ocular complaint - medications needed before surgery?
IV catheter in back leg?
Diabetic patients - insulin or not?

Question 23

What anaesthetic and positioning considerations should we have for ophthalmic surgery?

Answer 23

Smooth induction
Patient as still and steady as possible!
Monitoring equipment at back end wherever possible
Armoured ET tubes and T connectors
Neuromuscular blockade and ventilation

Question 24

How can we prep the eye for lid surgery?

Answer 24

Wear gloves
Apply copious amounts of lubricating gel to eye
Use small, clean, sharp clippers
Sharp scissors for eyelashes
Clip area as close to skin as possible without causing irritation
Flush hairs and lube away with saline

Question 25

What solutions should we use for scrubbing the eye area?

Answer 25

Povidone iodine solution Diluted with sterile saline 1:50 for globe 1:10 for eyelids 2 minute contact time Flush with sterile saline to prevent corneal toxicity

Question 26

What considerations should we have for enucleation surgery?

Answer 26

Consider local retrobulbar block Oculo-cardiac reflex (reflex bradycardia on eye pressure) Avoid traction on chiasm (avulsion can blind other eye) Haemorrhage - haemostasis options

Question 27

List some general eye area surgeries.

Answer 27

Entropion, mass removal Rhytidectomy (face-lift) Medial canthoplasty (pugs) Cherry eye Parotid duct transposition (dry eye)

Question 28

Describe corneal surgery.

Answer 28

Horizontal eye positioning (central eye often used) Ventilator and NMBs Remove damaged cornea Free / advancement graft

Question 29

What assessments should we carry out before cataract surgery?

Answer 29

Gonioscopy to check glaucoma risk post-op ERG to check for functional retina Ultrasound for tumour/angle check Post-op medication practicality

Question 30

What is gonioscopy?

Answer 30

Assess drainage angle Looking for signs of inherited glaucoma Patient conscious - LA drops

Question 31

Describe ocular ultrasound?

Answer 31

Patient can be conscious - local proxymetacaine desensitises cornea Lots of gel e.g. Optilube Assess structures of eye - lens structure, cataracts, retinal detachment, retrobulbar mass, FB

Question 32

Describe ERG (electroretinogram).

Answer 32

Records retinal electrical response to light stimulus Allows assessment of retina function Patient conscious/sedated

Question 33

What pre-op assessments should we carry out before ophthalmic surgery?

Answer 33

ERG High-frequency ultrasound Gonioscopy Full bloods and urinalysis to check for comorbidities Owners - cost, aftercare, lifelong medications and rechecks

Question 34

Describe typical post-op medications for ophtho patients.

Answer 34

Up to 12x daily in first week Steroids and NSAIDs topically to control uveitis Glaucoma medications to minimise IOP spike Antibiotics until wounds heal Lubricants for comfort

Question 35

Describe the role of NMBs in ophthalmic surgery.

Answer 35

'Central eye' achieved by paralysing extraocular muscles Also intercostals - need to manually ventilate patient Atracurium non-cumulative so safe in hepatic/renal patients

Question 36

What is brachycephalic ocular syndrome?

Answer 36

Lower medial entropion Shallow orbit, relative exophthalmos Macropalpebral fissure (excessive limbal/scleral exposure) Lagophthalmos (sleeping with lids incompletely closed) Medial caruncular trichiasis Nasal fold trichiasis Pigmentary ketatitis Epiphora

Question 37

What risks are elevated for diabetic ophthalmic patients?

Answer 37

Systemic hypertension Dry eye Delayed healing Infection

Question 38

What are the three layers of the tear film and what are their functions?

Answer 38

Lipid layer - prevents evaporation, aids distribution Aqueous layer - supplies corneal nutrition, antibacterial properties, removal and remodelling (proteases and antiproteases) Mucus layer - lubrication, refractive properties, anchors aqueous layer to cornea

Question 39

What is keratoconjunctivitis sicca?

Answer 39

Majority of cases are immune-mediated adenitis of lacrimal glands OR deficiency of aqueous tear

Question 40

How can we diagnose KCS?

Answer 40

Schirmer Tear Test AND concurrent clinical signs

Question 41

What are the common clinical signs of KCS?

Answer 41

Strings of adherent mucus Poor corneal clarity Poor corneal shine/poor Purkinje reflex Low STT reading