Ophthalmology Flashcards
(47 cards)
1
Q
What is distichiasis?
A
Hairs growing in an abnormal site
from the tarsal/Meibomian glands within the tarsal plate and emerging at the lid margin
2
Q
What is treatment of distichiasis?
A
- Plucking = regrow
- Electrolysis
- Tarsoconjunctival resection
3
Q
What solution should be used for the eye?
A
- Povidone iodine antiseptic solution
4
Q
What is ectopic (conjunctival) cilia?
A
- Emerge from the conjunctival surface and impinge directly on the eye
- Much more sporadic and far less common than distichiasis
- Far more painful - can cause shallow ulcers
- Alert - young dog (especially bulldogs) with a severely painful eye, possible shallow ulcer and no obvious cause
5
Q
How are ectopic cilia treated?
A
- Easy to deal with = cut out (scalpel / biopsy punch)
-go deep enough
6
Q
What is entropion? What can it cause?
A
- In rolling of lid margin = skin hairs impinge on eye
- Can cause corneal damage (masses of corneal granulation tissue)
7
Q
What is treatment of entropion?
What are consequences of treatment?
A
- Skin + muscle excision to pull eye margin out
-Hotz-Celsus procedure - Tx can lead to minor post-op ectropion = not a problem
8
Q
What breeds are predisposed to bad entropion at young age?
What should be done?
A
- Shar-pei - most need skin + muscle excision on all 4 eyelids eventually
- Tx = do not excise as they will grow
-temporarily ‘tacking’ is advised until mature
-suture good temporarily but cut in + migrate
9
Q
What breed of dogs have medial entropion with trichiasis?
A
- Pugs
10
Q
What breed get upper lid trichiasis syndrome?
Tx?
A
- Middle aged cocker spaniel upper eyelid syndrome
- Tx = Stades procedure
11
Q
What is the most common eyelid tumour in dogs?
A
- Sebaceous adenoma / epithelioma
-arises from tarsal gland
-benign
-require full thickness excision
12
Q
What is the function of the third eyelid?
A
- Secretory - 30% of aqueous tears
- Surface protection
- Tear film distribution
- Immunological
13
Q
What is cherry eye?
A
- Prolapse of the nictitans gland
14
Q
How can you manage cherry eye?
A
- Burying but preserving gland =
-preserves function
-expensive
-can fail - Excision of gland
-cheap + guarantee
-30% of aqueous tear capacity lost
15
Q
When would you excise the third eyelid?
A
- Only if neoplasia
16
Q
What is non-specific ocnjunctivitis?
Tx?
A
- diffuse redness without corneal, pupillary light reflex
or vision defects - Tx - Fusidic acid (only for STAPHs)
- Tx = Clinagel = Gentamicin (gram +ve & -ve)
17
Q
Other than conjunctivitis what else can cause red eye?
A
- Corneal ulcer or trauma
- Glaucoma
- Dislocated lens
- Uveitis
- Dry eye
18
Q
What produces portions of the tear film?
A
- Lipid = tarsal gland
- Aqueous = lacrimal + nictitans glands
- Mucus = conjunctival goblet cells
19
Q
What are causes of dry eye in the dog?
A
- Immune-mediated inflammation of the glands with secondary loss of function
- Neurological (“Dry eye – Dry Nose” syndrome)
- Sulphonamides / salazopyrin
- Distemper
- Chronic lid abnormalities
- Endocrine abnormalities contributory (hypothyroidism/diabetes)
20
Q
What are clinical signs of dry eye?
A
- Chronic conjunctivitis
- Dull appearance to the ocular surface
- Mucopurulent discharge - tenacious and adherent
- Discomfort
- Corneal ulceration (variable)
- Corneal vascularisation and pigmentation
21
Q
How can you quantify dry eye with tear production?
A
- 15mm = minimum
- 10-15mm = moderate dry eye
- <10mm = moderate to severe dry eye
22
Q
What is medical management of dry eye?
A
- Tear stimulants - cyclosporin (optimmune), Tacrolimus
- Tear film replacements - carbomer gel
23
Q
How can lacrimal drainage be monitored?
A
- Fluorescein drainage test =
-apply fluorescein with 2 drops of saline
-should see stain coming out of nose in 3-4minutes or less
24
Q
What is a corneal ulcer?
A
- Full thickness defect in epithelium
-causes pain + potential for progression
25
what are the 4 layers of the cornea?
* Epithelium
* Stroma
* Descemet's membrane
* Endothelium
26
What is the stroma susceptible to? what is this referred as?
* Enzymatic digestion =
-proteolysis
-keratomalacia
-collagenolysis
-melting
27
What can cause release of proteolytic enzymes?
* Bacteria - pseudomonas, B haemolytic streps
* Inflammatory cells
* Corneal cells
* Unexplained / sterile
28
What are signs of corneal perfortation?
* Sudden pain
* Convex protrusion of brown / black tissue with overlying fibrinous material
* Blood from eye
29
How does fluorescein work?
* Orange dye, turns green in alkaline conditions
* lipophobic = runs off intact epithelium
* hydrophilic = adheres to exposed stroma
* shows better with blue light
* Must flush with saline after exposure to eliminate false positives
* If depression and clear area in deep ulcer = not good + won't stain as down to descemet's membrane
30
What are primary causes of corneal ulceration?
* Factors causing direct mechanical damage
-eyelids, trauma, foreign bodies
* Factors contributing to an unhealthy superficial environment
-dry eye, poor blink
* Inherent corneal defects - indolent (boxer) ulcer
* Multifactorial - brachycephalics
31
What are non-specific medical therapy for corneal ulcers?
* Broad spec AB = gentamycin, ciprofloxacin, chloramphenicol + fluoroquinolone
* Lubricant frequently
* Atropine
* Acetylcysteine - for melting ulcers (anti-collagenase)
32
What are reconstruction techniques for corneal ulcers?
* Conjunctival pedicle graft
* Corneo-conjunctival transposition
33
What are indolent 'boxer' ulcers?
* Superficial chronic cornea epithelial damage (SCCED)
* epithelial only - not a concavity/crater
* mild oedema and loose under-run edges
* breed helpful - boxers, corgis, Staffies
* stain well with fluorescein
* vascularisation varies from none to extreme
* THEY DON'T HEAL - surgery
34
What are the 2 types of corneal foreign bodies?
* Adhere to surface
-flat/shallow curvature, little penetration, can be wiped out
* Intracorneal (usually thorns)
-easier with reasonable protrusion
-needle for removal
35
What animals are more prone to pigmentary keratitis?
* Brachycephalics
36
What breeds tend to get dermoids? (hair growing on eye)
* French bulldogs
37
What are pannus? breed predisposed? Tx?
* Inflammatory + vascular tissue advances across the cornea always from the ventrolateral direction
* GSD
* Topical cyclosporine / tacrolimus / topical steroids
38
What does the uvea consist of?
* Iris
* Ciliary body
* Choroid
39
What are causes of anterior uveitis?
* Spontaneous/idiopathic/immune-mediated
* Deep and/or infected ulcers
* Corneal trauma/laceration
* Remote sites of infection inc. pyometra
* Post intraocular surgery
* Specific intraocular infections
40
How do you treat uveitis?
* Mydriatics = relieve pain, reduce risk of adhesions
* Topical steroids +/or NSAIDs
* + oral steroids / NSAIDs
41
What is glaucoma? Causes?
* Abnormal rise in intraocular pressure
-always a problem of aqueous flow or drainage not over-production
42
Why is glaucoma serious?
* Painful
* Rapidly destroys retina + optic nerves
* Main cause of eye removal
43
What can cause secondary glaucoma?
* Uncontrolled inflammation
* Tumours
* Trauma
* Anterior lens luxation
* Perforations
* Severe intraocular haemorrhage
* Chronic retinal detachment
* Intraocular surgery
44
What are signs of acute glaucoma?
* Red eye
* Pain & lethargy
* Steamy cornea
* Non-responsive pupil
* Blindness
* Globe hard but normal size
45
What is tonometry / gonioscopy?
* Tonometry = measure of intraocular pressure
* Gonioscopy = assess drainage angle
46
What is topical treatment for glaucoma?
* Trusopt, azopt - topical carbonic anhydrase inhibitors
* Prostaglandin analogues - Xalatan
* Also prophylactic treatment of 'good eye'
47
