Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Equine Final Year > Equine Opthalmology > Flashcards

Equine Opthalmology Flashcards

1
Q

How can you routinely examine the equine eye?

A
  • Distance
  • Local blocks
  • Fluoroscein/ Rose Bengal dye
  • Focal light source

–Pen torch or transilluminator

  • Direct or panoptic ophthalmoscope
  • Transpalpebral ultrasound
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name 2 examining techniques that are rarely used to examine the eye (3)

A
  • Indirect ophthalmoscopy
  • Slit lamp evaluation of cornea/anterior chamber

–Can be used

•Tonometry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How would you do lacrimal nerve block?

A

•Needle subcutaneously just dorsal to the lateral canthus

–direct medially across the dorsal orbital rim during injection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How would you do an Infratrochlear nerve block (2-3ml)?

A

–Insert needle at medial canthus

–Needle directed along the bony notch on the dorsal rim of the orbit (toward the medial canthus)

•Desensitisation of medial eyelid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why would you do an infratrochlear nerve block?

A
  • Desensitisation of medial eyelid
  • Third eyelid remove
  • Medial canthus eye laceration repair
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How would you do a Zygomatic nerve block?

A

–Local anaesthetic along the ventral and lateral aspect of the bony orbit

•near the junction where the orbit begins to curve upward

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a Zygomatic nerve block good for?

A

•Desensitisation of the remainder of the lower lid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What 3 things might we look for in a pre purchase occular exam?

A

–Evidence of congenital/hereditary ocular disease

–Diseases that may lead to decreased vision

–Tumours (SCC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the uvea made up of?

A

–Iris

–Ciliary body

–Choroid – blood supply to retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why is the uvea important?

A

–Sight-limiting and a major cause of blindness if not appropriately diagnosed and aggressively treated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What equine uveitis do we see in the UK?

A

–Secondary to trauma

–Can be IM due to a variety of infectious organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What pathogenesis of uveitis do we see in USA and Europe?

A

–Equine recurrent uveitis

•Leptospirosis pomona/ grippotyphosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Name 2 breeds susceptible to Equine recurrent uveitis (3)

A

–German WB’s

–Appaloosas

–Coloured horses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Name presenting signs of equine uveiitis

A
  • OCULAR PAIN
  • Excess lacrimation
  • Blepharospasm
  • (Photophobia)
  • MIOSIS
  • Fibrin in anterior chamber
  • Corneal oedema
  • Chorioretinitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Name possible sequential events of equine uveitis

A
  • Synechiae
  • Iris rests
  • Change in iris pigmentation
  • Reduction in size of corpora nigrans
  • Cataracts
  • Retinal detachment
  • Glaucoma
  • BLINDNESS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the aims of equine uveitis treatment?

A

–Provide analgesia

•Ocular conditions are VERY painful

–Preserve vision

–Prevent or minimise recurrence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How can we treat equine uveitis? And why

A

•NSAID’s

–Systemic

•Atropine

–Topical

–Decreases pain when miosis reversed

–Decrease risk of synechiae and iris rest formation

•Corticosteroids

–With care

–NEVER if there is an ulcer

•Antibiotics

–Topical and BS

–Esp if using C/S’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the prognosis with equine uveitus?

A
  • Good if treated swiftly and aggressively
  • Warn clients that there may be a recurrence

–Can’t predict which horses

•Any changes visible in the eye of previous uveitis will cause the horse to be failed at PPE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is fibrin in anterior chamber ofte secondary to?

A

Blunt trauma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

C) What is hypopyon (inflam cells in anterior chamber) usuallt secondary to?

B) What do they have concurrent?

A

A) Sepsis

B) Uveitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where is hypopyon common?

A

Farm and neonates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 2 types of cataracts?

A
  • Congenital
  • ACquireed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the common caue of lens luxation and subluxation?

A

Trauma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When do we consider surgery with congenital cataracts?

A

–Cataracts

–No uveitis

–Intact retina

  • PLR/menace
  • Normal on U/S

–Vision impairment

–Appropriate personality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Congenital cataracts:

A) Uni or bilateral?

B) What can it be associated with?

A

A) Bilateral

B) Microphthalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What surgery is done on congenital cataract?

A

Phaecoemulsification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

ACquired cataracts:

A) What is it often secndary to? (2)

B) What do we also see in older horses?

A

A) Uveitis and trauma

B) Nuclear lendicular sclerosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Discuss the use of surgery in acquired cataracts

A

–Controversial for animals that have cataracts secondary to uveitis as prone to developing post-op complications

–Sight-limiting

•May wait until bilateral

–Risk of anaesthesia/recovery

–ERG and U/S useful to evaluate the retina if do

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Name 2 hereditary disorders of the retina (2)

A
  • Retinal colobomas (means absence of normal tissue)
  • Congenital retinal detachments
  • Chorioretinitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is Chorioretinitis secondary to?

A

In –utero infection with EHV-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How may EHV 1 chorioretinitis manifest?

A

–Bullet-hole lesions in retina (non tapetal area)

–Few OK

–Many – may restrict vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What lesion is seen with chorioretinitis?

A

•Bullet-hole or larger ‘butterfly-shaped’ lesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What can be seen in the eye of EMND (equine motor neurone disease)?

A

•Retinal pigment epithelial cell accumulation (ceroid lipofuscin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Name 2 things causing retina detachment (3)

A
  • UVEITIS
  • Trauma
  • Penetrating ocular wounds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Name 3 causes of atrophy of the optic nerve (5)

A

–UVEITIS

–Trauma

–Glaucoma

–Toxicity

–Blood loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What can cause Ischaemic ON neuropathy with the optic nerve (2)

A

–Int carotid occlusion for tx of GPM

–Blood loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What causes vitreal opacities (2)

A

–Fibrin

–Porphyrin metabolites (blood)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What are secondary issues of vitreuitis? (2)

A

–Cataracts

–Traction bands (Tugs retina and detachs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What can cause vitreal floaters? (3)

A
  • Age change
  • Secondary to uveitis
  • Can result in head-shaking in a V small proportion of horses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Normal retina:

A) What are the vessels?

B) What colour is the optic disc?

C What colour is the non tapetal fundus?

D) What colour is the tapetal fundus?

A

A) Paurangiotic

B) Pink

C) Dark brown

D) Yellow to green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Name 5 diseases of the eyelids, third eyelid, cornea and aqueous (9)

A

–Eyelid injury and entropion

–Congenital abnormalities

–Eyelid neoplasia

  • Sarcoids
  • Melanoma
  • Squamous cell carcinoma

–Habronema

–Ulcerative keratitis

•Bacterial

–Corneal abscess

  • Keratacomycosis (fungal keratitis)
  • Other keratitis – eosinophilic etc

–Viral keratitis (non-ulcerative / punctate keratitis)

–Glaucoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

How do we examine the equine eye?

A
  • Sedation
  • Perineural analgesia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Discuss the normal foals eye

A

–Low tear production

–Provide lubrication in the critically ill neonate

–Slow PLRs for first 5 days

–No menace for first 2 weeks

–Hyaloid artery remnants (hours)

–Prominent Y shaped sutures on lens

–Reduced corneal sensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How can we take diagnostic samples of the eye and what do we use these for?

A

–Swabs

  • Superficial bacteria (culture and sensitivity)
  • For rapidly progressive, deep ulcers or treatment failure

–Scrapes

  • Bacteria superficially
  • Fungal disease (lives on descemets membrane)

–Biopsy

  • Fungal disease
  • Viral/immune mediated disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Fluorescein:

A) What stains?

B) What does it confirm?

A

A) Corneal stroma

B) Epithelial defect/ulcer

46
Q

Rose bengal:

A) What does it identify?

A

–Identifies defects in pre-corneal tear film

–Mucin defects

  • Early fungal disease (multifocal lesions)
  • USE IN THE ACUTELY PAINFUL EYE
47
Q

How can you do tonometry in the horse?

A

Finger

Digital

48
Q

What are the common diseases of the foal?

A

•Corneal ulcers

–Reduced sensitivity

  • Uveitis – severe sepsis
  • Congital abnormalities

–Microphthalmos

–Persistent pupillary membranes

•Require no intervention – rarely affect vision

–Congenital cataracts

•Require surgery

–Congenital glaucoma

–Dermoids, lacrimal punctae agenesis

49
Q

Entropian in foals:

A) What is it commonly secondary to?

B) What does it requre?

C) What should you check for and how?

A

A) Dehydration and emaciation

B) Place a horizontal mattress

C) Stain for ulcer

50
Q

Melanomas:

A) Where is it common?

B) How can we treat?

A

A) Grey horse

B)

  • Excision, lid reconstruction and cryotherapy
  • Enucleation
51
Q

What is the most common eyelid neoplasia?

A

Sarcoids

52
Q

What are the 5 types of periocular sarcoids?

A

–Nodular

–Verrucose

–Fibroblastic

–Occult

–Mixed

53
Q

How might we treat periocular sarcoids?

A

–Topical brachytherapy Iridium wires 98% success

–Intralesional therapy with BCG 100% non recur

»± debulking ±5 fluoro-uracil

–Surgical excision – 50% non recur

–5FU – 67% non recur

54
Q

What is the pathogenesis of squamous cell carcinomas?

A

–UV light –

–Increases with age

–Breed susceptibility

55
Q

What is commonly affected with a squamous cell carcinoma?

A

Third eyelid

56
Q

What is a differential for squamous cell carcinoma?

A
  • Other neoplasma
  • Parasite
57
Q

What is the long term prognosis of squamous cell carcinoma?

A

–Rarely metastatic

–High long term recurrence

–Often require multiple therapies

58
Q

How can we treat squamous cell carcinomas?

A
  • Surgical excision – 50 % non recur
  • Immunotherapy BCG – ??
  • Chemotherapy – Cisplatin – 70% non recur, Mitomycine
  • Cryotherapy – 50-100% non recur
  • Brachytherapy – iridium – 90% non recur
59
Q

What lesions are seen with Habronemiasis? Where?

A

•Granulomatous lesions associated with granuloma in medial canthus

60
Q

How can we treat Habronemiasis?

A

–Ivermectin

  • Systemic NSAIDS

–Fly control

61
Q

What is the healing like with conreal disease?

A

Slow

62
Q

What is a melting ulcer?

A

Proteinases within PCTF (MMP9 and neutrophil elastase)

  • Normal defence / repair (PMNs, epithelial and stromal fibroblasts)
  • Production stimulated by bacteria and fungae
  • Proteinases produced by some bacteria
  • Collagenases produced by some pathogens
  • Grey liquefying appearance at edge of ulcer
63
Q

What is the normal defence/repare of melting ulcer?

A

»Production stimulated by bacteria and fungae

»Proteinases produced by some bacteria

»Collagenases produced by some pathogens

64
Q

Name common pathogens of the cornea

A
  • Staphyoloccus
  • Streptococcus
  • Pseudomonas
  • Aspergillus
  • Fusarium
  • quine Herpes Virus
65
Q

How do you deal with corenal ulceration?

A
  • Should receive prompt aggressive treatment
  • Infection should be considered in all ulcers
  • Concurrent uveitis should be addressed
66
Q

What are the clinical signs of corneal ulcer?

A

•Slight pain

–Blepharospasm

–Epiphora

–Photophobia

–Mild drooping of eyelids

67
Q

How do we diagnose corneal ulcer?

A

Stain

68
Q

How do you treat corneal ulcer?

A) First line/simple

B) Melting ulcer

C) Alternative

A

A) First line / simple ulcers

•Broad spectrum topic antimicrobials

–All impair ulcer healing

  • Chloramphenicol
  • Fucidic acid (gram +ve)
  • Triple anti-biotic (neomycin, gramicidin, polymixin B)

B) Melting ulcers

•Likely to involve pseudomonas

–Ciprofloxacin – Often resistance to gentamicin

C) Alternatives

•Ciprofloxacin (gentamicin resistant pseudomonas)

–Or chloramphenicol, polymixin B

•Cephalosporins for beta hemolytic streps

69
Q

How can we control melting ulcers?

A

–Block collagenase activity (Pseudomonas and beta hemolytic streps)

•PLASMA (horses own) – BETTER THAN SERUM

–Anti-proteinase activity

–Fresh every 5 days

•EDTA

–Binds calcium

•Acetylcysteine

–Can combine 2 or 3 for severe ulcers

–Consider hourly medication for first 12-24 hours

70
Q

How do you treat uveitis?

A

–Consider in all cases

–Topical atropine

–Systemic NSAIDS

71
Q

How do fungal ulcers cause issues?

A

•Usually colonisation of ulcer with commensal fungae

–Plant material

  • Proteinase release
  • Anti angiogenic
  • Affinity to Descemets membrane
72
Q

How can you treat fungal ulcers?

A

Topical

–Miconazole, itraconazole,

–May exacerbate uveitis initially

•Fungal death

73
Q

What is the benefit of bandaging contact lenses?

A

–Maintain apposition of healing ulcer

–Reduce pain

–Protection

74
Q

What is conjunctival pedical flaps used for?

A

–Deep melting ulcers

–Large superficial ulcers

–Corneal perforation

75
Q

Name 4 surgical therapies for an ulcer (6)

A
  • Bandage contact lense
  • Debride
  • Conjunctival pedical flaps
  • Third eyelid flaps
  • Temporary tarsorrhaphy (suture eyelids shut)
  • Amniotic membrane flaps
76
Q

Glaucoma:

A) What is it seen as a sequelae to?

B) Name clinical signs?

A

A) Uveitis

B)

–Dilated pupils

–Corneal band opacities

–Uveitis

–Optic nerve atrophy

–Poor vision

77
Q

Name 2 methods of preventing treatment failure (4)

A
  • Use solutions sprayed using an insulin needle
  • Lavage systems
  • Subpalpebral lavage systems
  • Nasolacrimal duct catheters
78
Q

How can we diagnose Superficial punctate keratitis?

A

–Subtle fluorescein staining

–Rose bengal retention

–Slit lamp (even on ophthalmoscope) can be useful

79
Q

How can we treat Superficial punctate keratitis? (3)

A

–EHV-2 implicated

–Topical antivirals

–Topical NSAIDS

80
Q

Where are Subpalpebral lavage devices placed?

A

Dorsal or central fornix

81
Q

What is the last resort option for a resistant ulcer?

A

Enucleation

82
Q

Which nerve block is this?

A

Lacrimal nerve block

83
Q

Which nerve block is this?

A

Infratrochlear nerve block

84
Q

Which nerve block is this?

A

Zygomatic nerve block

85
Q

What are these? What is the relevance?

A

Iridic granules

Horse has these which sit coming down from dorsal part or up from ventral of the iris

These should be the same on both eyes and roughly the same size –otheriwe you would question pathogenic

“sunglasses” for horses stop light hitting to the optic disc which sits ventral to the fundus

86
Q

What is this and what is the rlevance?

A

Normal retina assessment

Looks different to other species

Usually have the big y shape vessel supplying optic disc

Have trapetal funfudus which depends on the coat colour

Non tapetal fundus 0 optic disc sits

Blood supply looks like a sunshine

Eye folds in embryological development –often blips in otic disc and see changes in non tapetal fundus.

Changes at 6 o clock – chances are this is okay

87
Q

Label this eye ultrasound

A
  1. Retinochoriod unit
  2. Optic nerve head
  3. Cilaiary artery
  4. Extraocular muscle
  5. Retrobulbar fat
88
Q

What is going on here?

A

Copra nigra with shape

Synechiae anterior

Blocks of iris rest

Scar on cornea surface (probs trauma)

89
Q

What is going on here?

A

Cataract

Iis strand to right of lens (were posterior synechiea)

90
Q

What is going on here?

A

End stage

Third eye visible – microphtlamic

Shrunk down eye – left with reticulated patten on surface

Pigment on the cornea secondary to inflammation

91
Q

What is this?

A

Equine Uveitis

92
Q

What is this?

A

•Fibrin in the anterior chamber

93
Q

What is this?

A

Hypopyon

94
Q

What is this?

A

Cataract

95
Q

What is this?

A

•Retinal colobomas

96
Q

What is going on here?

A
97
Q

What do these show?

A

Chorioretinitis

98
Q

What condition has this finding?

A

EMND

99
Q

What do all these show?

A

Retinal detachments

100
Q

What disorder is shown?

A

Optic nerve disorders

101
Q

What is this?

A

Vitreitis

102
Q

What is this?

A
103
Q

What is this showing?

A

Perineural analgesia

104
Q

Which stain is this?

A

Fluorescein

105
Q

Which stain is this?

A

•Rose bengal

106
Q

What can be seen?

A
107
Q
A
108
Q

What is this?

A

Cornea ulcer

109
Q
A
110
Q
A

Equine Final Year (102 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions